BookPDF Available

Organic Farming in Europe: Economics & Policy. Vol. 6

Authors:

Abstract and Figures

Executive Summary Organic farming has become an important aspect of European agri- environmental policy. Since the implementation of EC Reg. 2078/92, the EU promotes organic farming based explicitly on its positive effects to the environment. The objective of this report is to contribute to a better understanding of organic farming's effects on the environment and to help clarify its possible contribution to European agri-environmental policy. Approach In this study, environmental and resource use impacts of organic farming are assessed relative to conventional farming systems. The primary source of information for this report is a survey of specialists in 18 European countries (all EU-member states plus Norway, Switzerland and the Czech Republic) using a structured questionnaire. These experts were asked to refer back to their national literature on the subject. The second important source of information used in this report is a literature search in international databases completed by the authors. For the purpose of this study, the OECD set of environmental indicators for the agricultural sector has been adapted, taking into consideration only those indicators that directly affect the system of organic farming. Following indicator categories will be evaluated: Ecosystem, natural resources, farm input and output, and health and welfare. As data availability on the subject has not always been satisfying, a qualitative multi-criteria analysis has been chosen as an approach. Due to the subjective elements involved therein, the report tries to achieve maximum transparency by showing step by step how each of the conclusions has been reached. Standards of organic farming Organic farming world-wide is defined by standards set by the organic farming associations themselves. In recent years it has also been defined by the EU. An important objective of these standards is the achievement of desired environmental goals. This and the pure existance and control of such standards is the most important aspect differentiating organic farming from conventional farming. In order to achieve desired environmental results two methods are used: 1. the regulation of the use of inputs to achieve an environmentally sensitive system; and 2. the requirement of specific measures to be applied or, in some cases, of the outcome of environmental or resource use. In general, the first method is more important and the second is more a supplement. There is considerable variety in the standards found which might influence both competitiveness environmental and resource performance. Impact of organic farming on indicators The results of environmental indicator assessment are summarised according to the following categories. Ecosystem: This category comprises the review of research results on floral and faunal biodiversity, habitat diversity and landscape conservation. The main findings are that organic farming clearly performs better than conventional farming in respect to floral and faunal diversity. Due to the ban of synthetic pesticides and N-fertilisers, organic farming systems provide potentials that result in positive effects on wildlife conservation and landscape. Potentially, organic farming leads to a higher diversity of wildlife habitats due to more highly diversified living conditions, which offer a wide range of housing, breeding and nutritional supply. However, direct measures for wildlife and biotope conservation depend on the individual activities of the farmers. Furthermore, research deficiencies were ascertained in connection with the measurement of habitat and landscape diversity. It needs to be stressed, that organic farming, as well as each form of agriculture, cannot contribute directly to many wildlife conservation goals. However, in productive areas, organic farming is currently the least detrimental farming system with respect to wildlife conservation and landscape. Soil: The impact of organic farming on soil properties has been researched comprehensively. Information is somewhat scarce only in respect to soil erosion. Results show that organic farming tends to conserve soil fertility and system stability better than conventional farming systems. This is due to mostly higher organic matter contents and higher biological activity in organically farmed soils than in conventionally managed. Furthermore, organic farming has a high erosion control potential. In comparison, no differences between the farming systems were identified as far as soil structure is concerned. Soil performance is, however, highly site specific. Ground and surface water: The research results reviewed show that organic farming results in lower or similar nitrate leaching rates than integrated or conventional agriculture. Farm comparisons show that actual leaching rates per hectare are up to 57% lower on organic than on conventional fields. However, the leaching rates per unit of output were similar or slightly higher. Critical areas for nitrate leaching in organic farming are ploughing legumes at the wrong time and the selection of unfavourable crops planted afterwards and composting farmyard manure on unpaved surfaces. However, consciousness of the problem and its handling has increased recently. Alternative measures have been developed and introduced in organic farming practise as well. Organic farming does not pose any risk of ground and surface water pollution from synthetic pesticides. Although incorrect organic farm management practices could indeed bear some potential risks for polluting ground and surface water, the detrimental environmental effects from organic farming tend to generally be lower than those from conventional farming systems. Thus organic farming is the preferred agricultural system for water reclamation areas. Climate and air: This section deals with the differences between organic and conventional farming with respect to greenhouse gases, NH3 emissions and air contamination due to pesticides. Research on CO2 emissions show varying results: On a per-hectare scale, the CO2 emissions are 40 - 60% lower in organic farming systems than in conventional ones, whereas on a per-unit output scale, the CO2 emissions tend to be higher in organic farming systems. Quantitative research results on N2O emissions in different farming systems are scarce. Based on deduction, experts conclude that N2O emissions per hectare on organic farms tend to be lower than on conventional farms, while the N2O emissions per kg of milk are equal or higher, respectively. However, due to the fact that almost no quantitative data is available, no definite differences between organic and conventional farming systems can be identified. Quantitative research results on CH4 emissions in different farming systems are also scarce. Experts estimate that organic farming has a lower CH4 emission potential on a per hectare scale, while CH4 emissions per kg of milk are estimated to be higher in organic dairy farms than in conventional ones. However, due to the insufficient data basis, again, no definite differences between the farming systems can be identified. Calculations of NH3 emissions in organic and conventional farming systems conclude that organic farming bears a lower NH3 emission potential than conventional farming systems. Housing systems and manure treatment in organic farming should aim for further reduction, although they provide fewer opportunities for abatement of emissions than slurry based systems. Due to the fact that synthetic pesticides are not permitted in organic farming, significantly lower air contamination is ensured than in conventional farming. Farm input and output: The studies reviewed about on-farm balances of nutrients, water and energy with respect to organic and conventional farming can be summarised as follows: nutrient balances of organic farms in general are close to zero. In all published calculations, the N, P and K surpluses of organic farms were significantly lower than on conventional farms. Negative balances were found for P and K. Most research studies reviewed indicate that energy consumption on organic farms is lower than on conventional farms. Energy efficiency calculated for annual and permanent crops is found to be higher in organic farming than in conventional farming in most cases. However, no research results on water use in organic and conventional farming systems are available. Animal health and welfare: Animal welfare and health are the subject of only a few comprehensive scientific studies. Hence, the actual situation provides the following picture: housing conditions and health status depend highly on farm specific conditions, thus housing conditions seem not to differ significantly between organic and conventional farms. Health status seems to be closely related to economic relevance of animal husbandry on the farm: Significantly fewer incidences of metabolic disorders, udder diseases and injuries were found when dairy production was properly managed. Prophylactic use of synthetic, allophatic medicines is restricted by some national standards and recently also by EU standards. Organic dairy cows tend to have a longer average productive life than conventional dairy cows. Although the application of homeopathic medicines should be preferred, conventional veterinary measures are permitted and used in acute cases of disease. Quality of food produced: No clear conclusions about the quality of organic food in general can be reached using the results of present literature and research results. The risk of contaminating food with pesticides and nitrate can be assumed to be lower in organically rather than in conventionally produced food. However, neither with respect to mycotoxin, heavy metal and PCB contents, and radioactive contamination, nor with respect to the contents of desirable food substances such as vitamins, nutrients, and aromatic compounds can significant differences between organic and conventional food be demonstrated. Given the discussed factors specific to animal products, a strong argument exists for the superiority of animal products from organic in comparison to conventional farming. The lack of comparative investigation of organic versus conventional farming is compensated by existing research results on the risk associated with conventional farming, such as antibiotic residuals in food and their effects on humans. Conclusion on the indicator assessment The review of the relevant literature with respect to organic farming and its impacts on the environment and resource use showed that organic farming performs better than conventional farming in relation to the majority of environmental indicators reviewed. In no indicator category did organic farming show a worse performance when compared with conventional farming. While detailed information is available as far as the two categories of soil and nutrients are concerned, a research deficit was ascertained for the indicator categories climate and air, animal health and food quality. Due to the lack of information, it was only possible to completely assess the performance of the different farming systems with respect to their environmental and resource use impacts on a per hectare scale. Policy relevance of the results One question among the many possible relevant policy ones can be answered firmly. How would an increase in the area organically farmed (e.g. doubling of the area) influence environmental and resource performance? Answer: an increase in the area of organic farming would clearly improve the total environmental and resource use performance of agriculture. It is not easy to answer further questions only using the material available about the influence of organic farming on the environment while maintaining constant food production levels or wether organic farming is part of a least-cost solution to meet agri-environmental goals. However, for policy purposes, the question of whether there are other agri-environmental means of achieving a desired level of environmental and resource performance that might be cheaper for society than organic production is of high relevance. A tentative answer to this question can only be based on theoretical reasoning. There are convincing arguments that the support of organic farming can be a useful part of the agri-environmental tool box, however, other, more specific instruments are also needed. Organic farming seems especially useful if broad environmental concerns are to be addressed, because it results in improvements for most environmental indicators. 
Content may be subject to copyright.
The
Environmental Impacts of
Organic Farming
in Europe
Organic Farming in Europe:
Economics and Policy
Volume 6
Matthias Stolze
Annette Piorr
Anna Häring
Stephan Dabbert
The individual contributions in this publication remain the responsibility of the authors.
The Environmental Impacts of Organic Farming in Europe /
Matthias Stolze, Annette Piorr, Anna Häring and Stephan Dabbert.
Stuttgart-Hohenheim: 2000
(Organic Farming in Europe: Economics and Policy; 6)
ISBN 3-933403-05-7
ISSN 1437-6512
Edited by Prof Dr Stephan Dabbert
Department of Farm Economics, University of Hohenheim, Germany
Dr Nicolas Lampkin
Welsh Institute of Rural Studies, University of Wales, Aberystwyth,
United Kingdom
Dr Johannes Michelsen
Department of Policy Studies, University of Southern Denmark, Esbjerg,
Denmark
Dr Hiltrud Nieberg
Institute of Farm Economics and Rural Studies, Federal Agricultural
Research Centre, Braunschweig (FAL), Germany
Prof Dr Raffaele Zanoli
Dipartimento di Biotecnologie Agrarie ed Ambientali, University of
Ancona, Italy
Technical
editor: Anna Häring
Published by: Prof Dr Stephan Dabbert
University of Hohenheim
Department of Farm Economics 410A
D-70593 Stuttgart
Germany
Tel: +49 (0)711 459-2543
Fax: +49 (0)711 459-2555
E-mail: ofeurope@uni-hohenheim.de
http://www.uni-hohenheim.de/~i410a/ofeurope/
© University of Hohenheim/Department of Farm Economics 410A, 2000.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval
system, or transmitted, in any form or by any means, electronically, mechanically, by
photocopying, recording or otherwise, without the prior permission of the copyright
owners.
Cover design and layout by walter + von schickh, Ettlingen, Germany
Printed and bound in Germany by Hago Druck & Medien, Karlsbad-Ittersbach
The authors gratefully acknowledge financial support from the Commission of the
European Communities, Agriculture and Fisheries (FAIR) specific RTD programme,
FAIR3-CT96-1794, „Effects of the CAP-reform and possible further development on
organic farming in the EU“.
Matthias Stolze, Annette Piorr, Anna Häring, Stephan Dabbert
University of Hohenheim
Department of Farm Economics 410A
D-70593 Stuttgart
Germany
Tel: +49 (0)711 459 2541
Fax: +49 (0)711 459 2555
Email: dabbert@uni-hohenheim.de
http://www.uni-hohenheim.de/ldw-bwl/
______________________________
This publication does not necessarily reflect the European Commission’s views and in no way anticipates the
Commission’s future policy in this area. Its content is the sole responsibility of the authors. The information
contained herein, including any expression of opinion and any projection or forecast, has been obtained from or is
based upon sources believed by the authors to be reliable but is not guaranteed as to accuracy or completeness.
The information is supplied without obligation and on the understanding that any person who acts upon it or
otherwise changes his/her position in reliance thereon does so entirely at his/her own risk.
i
Executive Summary
Organic farming has become an important aspect of European agri-
environmental policy. Since the implementation of EC Reg. 2078/92, the EU
promotes organic farming based explicitly on its positive effects to the
environment. The objective of this report is to contribute to a better
understanding of organic farming's effects on the environment and to help
clarify its possible contribution to European agri-environmental policy.
Approach
In this study, environmental and resource use impacts of organic farming are
assessed relative to conventional farming systems. The primary source of
information for this report is a survey of specialists in 18 European countries
(all EU-member states plus Norway, Switzerland and the Czech Republic) using
a structured questionnaire. These experts were asked to refer back to their
national literature on the subject. The second important source of information
used in this report is a literature search in international databases completed by
the authors.
For the purpose of this study, the OECD set of environmental indicators for the
agricultural sector has been adapted, taking into consideration only those
indicators that directly affect the system of organic farming. Following indicator
categories will be evaluated: Ecosystem, natural resources, farm input and
output, and health and welfare.
As data availability on the subject has not always been satisfying, a qualitative
multi-criteria analysis has been chosen as an approach. Due to the subjective
elements involved therein, the report tries to achieve maximum transparency by
showing step by step how each of the conclusions has been reached.
Standards of organic farming
Organic farming world-wide is defined by standards set by the organic farming
associations themselves. In recent years it has also been defined by the EU. An
important objective of these standards is the achievement of desired
environmental goals. This and the pure existance and control of such standards
is the most important aspect differentiating organic farming from conventional
farming. In order to achieve desired environmental results two methods are
used:
ii
1. the regulation of the use of inputs to achieve an environmentally sensitive
system; and
2. the requirement of specific measures to be applied or, in some cases, of the
outcome of environmental or resource use.
In general, the first method is more important and the second is more a
supplement. There is considerable variety in the standards found which might
influence both competitiveness environmental and resource performance.
Impact of organic farming on indicators
The results of environmental indicator assessment are summarised according to
the following categories.
Ecosystem: This category comprises the review of research results on floral and
faunal biodiversity, habitat diversity and landscape conservation. The main
findings are that organic farming clearly performs better than conventional
farming in respect to floral and faunal diversity. Due to the ban of synthetic
pesticides and N-fertilisers, organic farming systems provide potentials that
result in positive effects on wildlife conservation and landscape. Potentially,
organic farming leads to a higher diversity of wildlife habitats due to more
highly diversified living conditions, which offer a wide range of housing,
breeding and nutritional supply. However, direct measures for wildlife and
biotope conservation depend on the individual activities of the farmers.
Furthermore, research deficiencies were ascertained in connection with the
measurement of habitat and landscape diversity. It needs to be stressed, that
organic farming, as well as each form of agriculture, cannot contribute directly
to many wildlife conservation goals. However, in productive areas, organic
farming is currently the least detrimental farming system with respect to wildlife
conservation and landscape.
Soil: The impact of organic farming on soil properties has been researched
comprehensively. Information is somewhat scarce only in respect to soil
erosion. Results show that organic farming tends to conserve soil fertility and
system stability better than conventional farming systems. This is due to mostly
higher organic matter contents and higher biological activity in organically
farmed soils than in conventionally managed. Furthermore, organic farming has
a high erosion control potential. In comparison, no differences between the
farming systems were identified as far as soil structure is concerned. Soil
performance is, however, highly site specific.
iii
Ground and surface water: The research results reviewed show that organic
farming results in lower or similar nitrate leaching rates than integrated or
conventional agriculture. Farm comparisons show that actual leaching rates per
hectare are up to 57% lower on organic than on conventional fields. However,
the leaching rates per unit of output were similar or slightly higher. Critical
areas for nitrate leaching in organic farming are ploughing legumes at the wrong
time and the selection of unfavourable crops planted afterwards and composting
farmyard manure on unpaved surfaces. However, consciousness of the problem
and its handling has increased recently. Alternative measures have been
developed and introduced in organic farming practise as well. Organic farming
does not pose any risk of ground and surface water pollution from synthetic
pesticides. Although incorrect organic farm management practices could indeed
bear some potential risks for polluting ground and surface water, the detrimental
environmental effects from organic farming tend to generally be lower than
those from conventional farming systems. Thus organic farming is the preferred
agricultural system for water reclamation areas.
Climate and air: This section deals with the differences between organic and
conventional farming with respect to greenhouse gases, NH3 emissions and air
contamination due to pesticides. Research on CO2 emissions show varying
results: On a per-hectare scale, the CO2 emissions are 40 - 60% lower in organic
farming systems than in conventional ones, whereas on a per-unit output scale,
the CO2 emissions tend to be higher in organic farming systems. Quantitative
research results on N2O emissions in different farming systems are scarce.
Based on deduction, experts conclude that N2O emissions per hectare on
organic farms tend to be lower than on conventional farms, while the N2O
emissions per kg of milk are equal or higher, respectively. However, due to the
fact that almost no quantitative data is available, no definite differences between
organic and conventional farming systems can be identified. Quantitative
research results on CH4 emissions in different farming systems are also scarce.
Experts estimate that organic farming has a lower CH4 emission potential on a
per hectare scale, while CH4 emissions per kg of milk are estimated to be higher
in organic dairy farms than in conventional ones. However, due to the
insufficient data basis, again, no definite differences between the farming
systems can be identified. Calculations of NH3 emissions in organic and
conventional farming systems conclude that organic farming bears a lower NH3
emission potential than conventional farming systems. Housing systems and
manure treatment in organic farming should aim for further reduction, although
they provide fewer opportunities for abatement of emissions than slurry based
systems. Due to the fact that synthetic pesticides are not permitted in organic
farming, significantly lower air contamination is ensured than in conventional
farming.
iv
Farm input and output: The studies reviewed about on-farm balances of
nutrients, water and energy with respect to organic and conventional farming
can be summarised as follows: nutrient balances of organic farms in general are
close to zero. In all published calculations, the N, P and K surpluses of organic
farms were significantly lower than on conventional farms. Negative balances
were found for P and K. Most research studies reviewed indicate that energy
consumption on organic farms is lower than on conventional farms. Energy
efficiency calculated for annual and permanent crops is found to be higher in
organic farming than in conventional farming in most cases. However, no
research results on water use in organic and conventional farming systems are
available.
Animal health and welfare: Animal welfare and health are the subject of only a
few comprehensive scientific studies. Hence, the actual situation provides the
following picture: housing conditions and health status depend highly on farm
specific conditions, thus housing conditions seem not to differ significantly
between organic and conventional farms. Health status seems to be closely
related to economic relevance of animal husbandry on the farm: Significantly
fewer incidences of metabolic disorders, udder diseases and injuries were found
when dairy production was properly managed. Prophylactic use of synthetic,
allophatic medicines is restricted by some national standards and recently also
by EU standards. Organic dairy cows tend to have a longer average productive
life than conventional dairy cows. Although the application of homeopathic
medicines should be preferred, conventional veterinary measures are permitted
and used in acute cases of disease.
Quality of food produced: No clear conclusions about the quality of organic
food in general can be reached using the results of present literature and
research results. The risk of contaminating food with pesticides and nitrate can
be assumed to be lower in organically rather than in conventionally produced
food. However, neither with respect to mycotoxin, heavy metal and PCB
contents, and radioactive contamination, nor with respect to the contents of
desirable food substances such as vitamins, nutrients, and aromatic compounds
can significant differences between organic and conventional food be
demonstrated. Given the discussed factors specific to animal products, a strong
argument exists for the superiority of animal products from organic in
comparison to conventional farming. The lack of comparative investigation of
organic versus conventional farming is compensated by existing research results
on the risk associated with conventional farming, such as antibiotic residuals in
food and their effects on humans.
v
Conclusion on the indicator assessment
The review of the relevant literature with respect to organic farming and its
impacts on the environment and resource use showed that organic farming
performs better than conventional farming in relation to the majority of
environmental indicators reviewed. In no indicator category did organic farming
show a worse performance when compared with conventional farming. While
detailed information is available as far as the two categories of soil and nutrients
are concerned, a research deficit was ascertained for the indicator categories
climate and air, animal health and food quality. Due to the lack of information,
it was only possible to completely assess the performance of the different
farming systems with respect to their environmental and resource use impacts
on a per hectare scale.
Policy relevance of the results
One question among the many possible relevant policy ones can be answered
firmly. How would an increase in the area organically farmed (e.g. doubling of
the area) influence environmental and resource performance? Answer: an
increase in the area of organic farming would clearly improve the total
environmental and resource use performance of agriculture.
It is not easy to answer further questions only using the material available about
the influence of organic farming on the environment while maintaining constant
food production levels or wether organic farming is part of a least-cost solution
to meet agri-environmental goals. However, for policy purposes, the question of
whether there are other agri-environmental means of achieving a desired level
of environmental and resource performance that might be cheaper for society
than organic production is of high relevance. A tentative answer to this question
can only be based on theoretical reasoning. There are convincing arguments that
the support of organic farming can be a useful part of the agri-environmental
tool box, however, other, more specific instruments are also needed. Organic
farming seems especially useful if broad environmental concerns are to be
addressed, because it results in improvements for most environmental
indicators.
v
i
Table of contents
Executive Summary i
Table of contents vi
List of figures and tables viii
Abbreviations x
1 Introduction 1
2 The methodological challenge 3
2.1 The methodological basis 3
2.2 Information sources 5
2.3 Environment and resource use variables 6
2.3.1 Concepts of indicators 7
2.3.2 Indicator adaptation 8
2.3.3 Terms of reference 11
2.3.4 Aggregation of information 13
3 Definitions and standards of organic farming
in relation to environment and resource use 15
3.1 International standards 16
3.1.1 IFOAM 16
3.1.2 European Union 18
3.2 National Regulations 19
3.3 Summary and Conclusions 21
4 Impacts of organic farming on the environment and resource use 23
4.1 Ecosystem 23
4.1.1 Species diversity 23
4.1.1.1 Floral diversity 24
4.1.1.2 Faunal diversity 26
4.1.2 Habitat diversity 29
4.1.3 Landscape 31
4.1.4 Summary : Ecosystem 33
4.2 Natural resources 35
4.2.1 Soil 35
4.2.1.1 Soil organic matter 36
4.2.1.2 Biological activity 38
vii
4.2.1.3 Soil structure 41
4.2.1.4 Erosion 41
4.2.1.5 Summary: Soil 43
4.2.2 Ground and surface water 44
4.2.2.1 Nitrate leaching 45
4.2.2.2 Pesticides 50
4.2.2.3 Summary: Ground and surface water 52
4.2.3 Climate and air 53
4.2.3.1 CO2 54
4.2.3.2 N2O 56
4.2.3.3 CH4 58
4.2.3.4 NH3 60
4.2.3.5 Pesticides 62
4.2.3.6 Summary: Climate and air 62
4.3 Farm input and output 63
4.3.1 Nutrient use 64
4.3.2 Water use 68
4.3.3 Energy use 69
4.3.4 Summary: Farm input and output 73
4.4 Health and welfare 74
4.4.1 Animal health and welfare 74
4.4.1.1 Husbandry 75
4.4.1.2 Health 76
4.4.1.3 Summary: Animal welfare and health 78
4.4.2 Quality of produced food 80
4.4.2.1 Plant products 80
4.4.2.2 Animal products 83
4.4.2.3 Summary: Quality of produced food 84
4.5 Conclusion 86
5 Agri-environmental policy relevance
of the indicator analysis of organic farming 91
6 References 98
List of contributors 126
v
iii
List of figures and tables
Figure 1: Evaluation frame: environmental indicators for farming systems 9
Figure 2: Policy relevant questions with respect to the environmental
and resource effects of organic farming 92
Table 2-1: The complexity of farming system comparisons 4
Table 2-2: Environmental indicators for organic farming based on
the OECD list of environmental indicators for agriculture 11
Table 2-3: Assessment scale used for indicator evaluation 14
Table 4-1: Number of species in six peach orchards of
two organic and two conventional farms 27
Table 4-2: The proportion of ecologically diversified land area per farm (%) 30
Table 4-3: Assessment of organic farming's impact on the indicator category
"ecosystem" compared with conventional farming 34
Table 4-4: Changes of soil organic matter content
from initial values in different farming systems 37
Table 4-5: Soil microbiological properties after 12 years of farming -
relative results to conventional (=100%), DOC-trial 40
Table 4-6: Assessment of organic farming's impact on the indicator subcategory
"soil" compared with conventional farming 43
Table 4-7: Nitrate leaching rates from organic farming relative to
conventional farming systems (farm comparisons) 46
Table 4-8: Nitrate screening in water protection areas: Results of
kg Nmin- N/ha content* of organic fields relative to conventional fields 48
Table 4-9: Reduction of pesticide input in different farming systems 51
Table 4-10: Assessment of organic farming's impact on the indicator subcategory
"Ground and surface water " compared with conventional farming 53
Table 4-11: CO2 emissions (kg) in winter wheat and potato production -
comparative calculations from different authors 55
Table 4-12: Mean CO2 emissions per hectare: calculations for Germany (in t/ha) 56
Table 4-13: Assessment of organic farming's impact on the indicator subcategory
"climate and air " compared with conventional farming 63
Table 4-14: Nitrogen flow and efficiency on conventional and
organic mixed dairy farms (in kg/ha/year) 65
Table 4-15: Examples for N, P, K balances (kg/ha) from
on-farm investigations in Germany 66
Table 4-16: Examples for N, P, K balances (kg/ha) comparing organic
resp. conventional farms from different European countries 66
Table 4-17: Calculated scenarios for N-surplus of dairy farms
in Denmark (maintaining the present milk production level) 68
Table 4-18: Calculations of farm energy consumption (in GJ/ha and year) 69
Table 4-19: Calculations of energy consumption of different crops 70
Table 4-20: Energy efficiency (input/output) of various crops 71
Table 4-21: Ratio between energy input and energy output
of different peach orchard farming systems 72
i
x
Table 4-22: Assessment of organic farming's impact on the indicator category
"Farm input and output " compared with conventional farming 74
Table 4-23: Assessment of organic farming's impact on the indicator subcategory
"Animal welfare and health " compared with conventional farming 80
Table 4-24: Assessment of organic farming's impact on the indicator subcategory
"Quality of produced food" compared with conventional farming 85
Table 4-25: Detailed assessment of organic farming's impact on the environment and
resource use compared with conventional farming 86
Table 4-26: Assessment of organic farming's impact on the environment and
resource use compared with conventional farming: Summary 88
Table 4-27: Rating of the importance of environmental and resource use effects
of organic farming according to country specific expert opinion.
Mean data from 18 countries 89
Table 5-1: Typology of policy relevant questions 96
x
Abbreviations
14C Carbon 14
AGÖL Arbeitsgemeinschaft Ökologischer Landbau
AGROBIO Associação Portuguesa de Agricoltura Biologica
AMAB Associazione Marchigiana Per L`Agricoltura Biológica
ANL Akademie für Naturschutz und Landschaftspflege
ATP Adenosintriphosphat
BSE Bovine Spongiform Encephalopathy
BTO British Trust for Ornithology
C Carbon
CAP Common Agricultural Policy
CH4 Methane
CO2 Carbon dioxide
HCO3 Hydrogen carbonate
CRAE Consejo Regulador de Agricoltura Ecológica
Ct Total carbon
DOC Dynamic-Organic-Conventional
DSR Driving Force-State-Response
EC European Community
EC Reg EC Regulation
FU Fertiliser Unit
GJ Gigajoule
GMO Genetically Engineered Organisms
ha Hectare
IFOAM International Federation Of Organic Agriculture Movements
K Potassium
kg Kilogram
KRAV Organic Biologique Ekologisk (certified by KRAV)
LØJ Landsforeningen Økologisk Jordbrug
LU Livestock Unit
MECU Millions of ECU
N Nitrogen
N2O Dinitrogenoxide
xi
NH3 Ammonia
Nmin-N Mineralisable nitrogen
NOx Nitrous oxides
Nt Total nitrogen
OECD Organisation for Economic Co-operation and Development
P Phosphorous
PCB Polychlorinated biphenyls
SIR Substrate Induced Respiration
t Metric tons
USLE Universal Soil Loss Equation
x
ii
1
1 Introduction
Agri-environmental policy is a European policy area in which organic farming
has become a notable aspect. Since the implementation of EC Reg. 2078/92, the
EU promotes organic farming explicitly due to its positive effects on the
environment. In 1997, the EU expenditure on organic farming support through
agri-environment programs (EC Reg. 2078/92) increased to 261 MECU or
10.7% of the total EU agri-environment budget (Lampkin et al. 1999). In 1997,
Belgium, Denmark, Greece and Italy have spent more than 20% of their agri-
environment budget on organic farming. This support of organic farms is
substantial in some European countries. Official government statements issued
in 18 European countries testify to the growing importance of organic farming
in agri-environment policy. For the majority of European governments (CH,
DE, DK, ES, FI, FR, GB, IE, NL, NO, and SE) the environmental effects of
organic farming are indeed policy relevant, while at least in one quarter of the
countries mentioned above, organic farming plays the central role in national
agri-environment policy. A major reason for the policy support of organic
farming is that the environmental effects of this system are assumed to be
positive. These factors give rise to the following pivotal question:
Is EU support of organic farming justified on the grounds of the
environmental benefits to be gained?
This report specifically focuses on the assessment of organic farming's
contribution to the policy objective of decreasing any negative and enhancing
any positive effects of agriculture on the environment and resource use. Thus, in
order to contribute to a better understanding of organic farming’s environmental
effects and to help clarify the question asked above, this report pursues the
following objectives on an European level:
to give an up-to-date inventory of the environmental impacts of organic
farming;
to identify the positive and negative environmental effects of organic
farming and their extent;
to evaluate the system organic farming with respect to environmental and
resource use impacts; and
to discuss the results gained in the context of the EU agri-environment
policy.
2
The following section of this report focuses on the discussion of methodological
questions. In the third section both international and national level organic
farming standards are presented and discussed with respect to their contribution
to environmental and resource use effects of organic farming. In section four the
environmental and resource use impacts of organic farming are analysed
according to the concept of environmental indicators developed in section two.
The section results in a matrix of environmental and resource use effects of
organic farming. This leads to an evaluation of the system of organic farming.
In the last section, the results gained are discussed in the context of organic
farming as an agri-environment policy option.
3
2 The methodological challenge
A number of methodological questions which are essential for the outcome of
this study arise as the objective of this report, to assess the environmental and
resource use effects of organic farming, is approached:
Which methodological basis should be chosen for an analysis of the
environmental and resource use effects of farming systems?
How can detailed information be collected on a European level?
What are the correct environmental variables to be considered?
How can detailed information be aggregated to become relevant to policy?
These questions constitute the methodological challenge of this study and
therefore require a more detailed discussion.
2.1 The methodological basis
Generally, there are two possibilities of evaluating the environmental and
resource use effects of organic farming. First the system can be assessed by
evaluating the degree to which certain goals based on target values are met. This
environmental impact assessment approach requires the definition of target
values for the whole area of concern. As such target values are not sufficiently
available, this first approach is currently not applicable. Another, more policy
relevant approach is the evaluation of organic farming's environmental and
resource use impacts relative to a reference system. Such a comparison allows a
judgement as to which extent organic farming performs ”better” or ”worse” in
comparison to the reference system. There is no question about the fact that
conventional farming is the appropriate reference system. The methodological
dilemma starts with the definition of the correct set for comparison. Neither of
the terms organic or conventional farming describe a stable state or a constantly
valid process. Farming systems develop dynamically providing room for a range
of system variations. The essential point which needs to be discussed in more
detail is the selection of the specific systems to be compared as these have a
strong influence on the results.
Table 2-1 illustrates the variety of different conventional and organic systems
which are likely to differ with respect to their environmental and resource use
effects. In simplified terms, three different degrees of environmental
friendliness can be distinguished for each farming system:
4
typical as found in practice;
using best management practice; and
using best management practice plus specific measures to reduce
environmental and resource use impacts.
These different categories develop nine possible paired comparisons. But,
which of these possible paired comparisons between organic and conventional
farming is the right one? The important point here is that the correct comparison
in Table 2-1 depends on the question asked. Therefore, C1-O1 would be the
right comparison if information is desired on how conventional and organic
farming perform in practice, or if the consequences of an increased extent of
organic farming were to be assessed.
In the European context, each farming system or variation respectively has
characteristics and nuances specific to each country. Consequently, we find
varying definitions among European countries with respect to both organic
(organic standards, implementation of EU Reg. 2092/91) and conventional
(integrated farming) farming systems. For integrated systems especially, a clear
and distinct definition is not possible on a European level. Thus, although it is
generally possible to distinguish precisely enough what is organic and what is
conventional, in the overall context it is not possible to define the boundaries of
farming systems exactly for a in-pairs comparison.
Table 2-1: The complexity of farming system comparisons
Conventional systems Organic systems
Conventional C1 as typically found
in practice Organic O1 as typically found
in practice
Integrated C2 using best management
practices Best organic
management O2 using best management
practices within the
organic system
Integrated plus
specific agri-
environ-mental
measures
C3 integrated plus
specific measures
decreasing
environmental and
resource use, e.g.
providing exclusive
areas for ”pure nature”
Best organic
management
plus specific
agri-environ-
mental
measures
O3 best organic
management plus
specific measures
decreasing
environmental and
resource use, e.g.
providing exclusive
areas for ”pure nature”
To make matters even more difficult, the environmental and resource use
impacts of agriculture not only depend on the varieties in the system and the
environmental management levels but also on the following factors: farm type,
degree of specialisation, level of intensity, site specific aspects, and individual
management abilities of the farmer. The inclusion of all these factors mentioned
would enhance the complexity of the analysis considerably. Furthermore, the
analysis would, of course, require a complete basis of information about all
existing variations of farming systems and about all factors affecting the
environment and resource use. However, we cannot begin to assume this ideal
case. Hence, one major problem this study faces is that of data availability.
5
The fact of insufficient information forced us to simplify the definition of
organic and conventional farming. Thus, in this study, all variations of
conventional and integrated farming are combined in the term conventional
farming. Analogously, we use the term organic farming for all types and
national variations of organic farming systems which correspond in the broader
sense to EC Reg. 2092/91. Therefore, the important factor ‘data availability‘
finally determined the precision of the comparison.
2.2 Information sources
The primary sources of information for this study are documented research
results published in the countries investigated, accompanied by investigations to
clarify the country specific policy background and including expert assessment.
The methodology of an expert survey has been chosen for data collection. The
expert survey conducted in 18 European countries (all EU-member states, plus
Norway, Switzerland and the Czech Republic) uses a questionnaire that consists
of two types of questions: questions that are to be answered on the basis of
literature reviews and expert knowledge, and those based on additional surveys
that are to be performed by national experts.
In order to ensure the inclusion of both on-going research and grey literature, as
well as country specific aspects in each country investigated, a recognised
expert in organic farming native to that country has been contracted. These
national experts are primarily responsible for responding to the questionnaire
but also for performing further data collections in the respective country. Thus,
the national experts act as both respondent and surveyor. In order to deal with
this situation, the questionnaire’s design included guidelines and an example of
how to fill in the questionnaire.
Because of the challenges faced by covering 18 European countries (e.g. the
resulting language problems), and in order to increase work efficiency, the
national experts were asked to review and summarise the relevant literature.
Due to this fact, data analysis was confronted with the problem that only
research material documented in English and German could be double-checked
by the authors of this report. The reviews of material written in other languages
represent the individual focus of the contracted expert. Data quality delivered is
correlated with both data availability and expert knowledge. A comprehensive
literature review in international scientific databases was part of each expert
survey.
6
It would be highly desirable to be able to disaggregate information on the
relative performance of organic farming compared to conventional with respect
to an environmental dimension (subject) by farm type and region. However, the
quality of data mainly allows data analysis and interpretation by subject. Only in
some parts of this report could country specific aspects and differences be
analysed. The reason for this is that the studies reviewed have been conducted
independently and do not follow a common methodology. Thus, they often
support or reject general statements on a given subject, but the results can in
many cases not be used for quantitative comparisons. In addition to uneven
methodology, information is missing on several topics because no studies have
been conducted. Therefore, another aim of this study will be to identify those
areas where information and research is lacking with respect to environmental
indicators.
2.3 Environment and resource use variables
The selection of variables is of central importance for the outcome of a system
comparison on environmental and resource use impacts. The ideal variable or
set of variables respectively provides information and describes the state of
environmental phenomena with certain significance. Thus, applying a set of
variables should make it possible to monitor and assess the state of the
environment, to identify changes and trends, to transmit scientific data to
become relevant for policy, and to evaluate already implemented policy
measures. The concept of environmental indicators is broadly accepted as an
adequate tool. Accordingly, an indicator is defined as a parameter or a value
derived from parameters, which indicates the state of the environment with
significance extending beyond that which is directly associated with a parameter
value. A parameter’s definition in this context is a property that is measured or
observed (OECD 1994). Pieri et al. (1996) states that the purposes of indicators
are as follows:
to select the most significant information;
to simplify complex phenomena;
to quantify information, so that its significance is more readily apparent; and
to communicate information, particularly between data collectors and data
users.
7
2.3.1 Concepts of indicators
After initiation by the AGENDA 21 various institutions started working on
environmental indicator concepts. A comprehensive report on existing
approaches of environmental indicator concepts is given by Walz et al. (1995).
They describe that most of the concepts already published and available for
international comparisons suffer from
a) a status of immaturity with regard to data availability, definition of target
values, conceptual uncertainty about aggregation level and indicator
definitions, and indicator ambiguity;
b) an explicit regional focus on either industrial, fast-developing, or developing
country problems; and
c) a restriction to indicators that can be measured only monetarily.
Currently the most important and the most advanced indicator concept in the
area of environment and resource use has been presented by the OECD. The
OECD concept has been developed with regard to environmental and resource
use effects in order to enable the analysis of country-specific situations, to
evaluate environmental policies and to measure environmental quality.
Furthermore, the OECD provides a set of environmental indicators adapted
exclusively for the agricultural sector. This concept is based on the Driving
Force - State - Response framework (DSR). The advantage of such a framework
is that environmental indicators can be identified and developed upon solid
concepts and methodology. In this context, the term "Driving forces" describes
those elements that cause changes in the state of the environment. The term
"State" or condition refers to changes in environmental conditions that may
arise from various driving forces. "Responses" refer to the reaction by groups in
society or policy makers to the actual and perceived changes in the State
(OECD 1997). Generally, the DSR-framework aims at providing a system that
makes a reduction of the parameters investigated possible. This simplification
results in a more workable communication structure.
There is a general agreement within the research community that the DSR-
framework is the most perfected and therefore the highest internationally
accepted framework. This enhances the international standard of environmental
indicators (Münchhausen and Nieberg 1997, Walz et al. 1995). Due to these
reasons and due to the international approach of the project, this study relies on
the set of environmental indicators for the agricultural sector developed within
the DSR-framework by the OECD.
8
2.3.2 Indicator adaptation
The OECD set of environmental indicators for the agricultural sector contains
several sub-categories assigned to each of the three DSR-elements (OECD
1997):
Driving Force sub-categories:
Environment
Economy and social
Farm inputs and outputs
State sub-categories:
Ecosystem
Natural resources
Health and welfare
Responses sub-categories:
Consumer reaction
Agro-food chain responses
Farmer behaviour
Government policies
These sub-categories have been defined in accordance with the OECD's
intention of analysing country-specific situations, evaluating environmental
policies and measuring environmental quality. The purpose of this study,
however, is somewhat different from that of the OECD. In this study, we want
to assess the environmental and resource use effects of organic farming relative
to conventional farming in a European context. Thus, we need to concentrate on
analysing and evaluating system effects rather than evaluating policies. For our
analysis we need to narrow down and adapt the original OECD indicator set.
Figure 1 illustrates this adaptation. The agricultural sector in Europe provides
the external frame within which the sub-categories are affected by the DSR-
elements. Focusing on the farming system as a part of the whole sector requires
limiting the analysis to those variables which are directly linked to the
characteristic of a farming system and those directly influenced by a farming
system. These variables are to be identified on the basis of those sub-categories,
which are enclosed in the evaluation frame shown in Figure 1.
Accordingly, as far as driving forces are concerned, external factors are those
which actually have a general effect on the farm because of the condition of the
farm site (environment) and the economic and social framework. These factors
might indubitably be beneficial or detrimental to a farming system. Both factors
are, nevertheless not a defined characteristic of a farming system nor does a
farming system generally affect these factors. According to the OECD concept,
the only driving force to be
considered is farm inputs and outputs, including the impact of chemical use,
energy use, water resource use, level and mix of farm crop and livestock
outputs, as well as farm management practises.
9
EXTERNAL FRAME - SECTOR VARIABLE
S
Dri ving
Force
Ag
ro-
Ag
ro-
Responses
State
Environmental
frame
w
or
k
EVALUATION FRAME - SYSTEM VARIABLE
S
Farmi ng System
Farm in put
and out put
Ecos
y
stem Nat ural
resources Healt h
and wel far e
Consumer
react i on
Farmer
reaction
Govern men t
policies
Ag
ro-Food
chai n r esponse s
Economical
and social
fr amewor k
Figure 1: Evaluation frame: environmental indicators for farming systems
In contrary to the driving forces, all State sub-categories are included in the
evaluation frame because farming systems have an effect on the ecosystem, the
natural resources and on health and welfare. Thus, biodiversity and natural
habitats are parts of the ecosystem category, while the variables soil, water,
climate and air are considered under the natural resources category. The health
and welfare category has been expanded and now includes system effects on the
farmer (e.g. pesticide spray), and on consumers as part of the food quality
indicator. Animal health and welfare is included in this sub-category, too.
Therefore, this study is not limited to an analysis of physical parameters of
environment and resources but includes the analysis of certain kinds of
(sometimes partially) public goods like health and welfare as well.
While the distinction between internal and external categories is unambiguous
for the State and Driving Force categories, the situation is more complicated as
far as the Response categories consumer reaction, agro-food chain responses
and government policies are concerned. These Response categories can
influence the legal framework of farming systems both directly and
dynamically, for example by changes in EC Reg. 2092/91.
10
However, measuring these impacts would result in measuring indicators, which
are already evaluated in the Driving Force and State categories. Thus, no
Response category will be directly discussed. Because the organic farming
system is evaluated in comparison to that of conventional farming, the most
important differentiating element the legal framework of organic farming can
not only be considered in the Response category, but as some sort of Driving
force as well. Therefore, in this special case, the organic standards and
regulations are discussed partially in section 3.
The regulatory and policy environment as well as its institutional and marketing
aspects, are separate questions of concern which will not be dealt with in this
study. Information about these subjects can be found in Lampkin et al. (1999)
and Michelsen et al. (1999).
To summarise, the indicators to be looked at in this study adhere to the
restrictions on indicators, which are in the evaluation frame shown in Figure 1.
Basically, they correspond with the respective environmental indicators for
agriculture suggested by the OECD (1997). The complete list of indicators,
including the name of the section they will be analysed in, is shown in Table 2-
2.
11
Table 2-2: Environmental indicators for organic farming based on the OECD list
of environmental indicators for agriculture
Indicator category Indicator
Ecosystem
Floral diversity
Faunal diversity
Habitat diversity
Landscape
Natural Resources
Soil Organic matter
Biological activity
Structure
Erosion
Ground and surface water Nitrate leaching
Pesticides
Nutrient load
Climate and air NH3
CO2
N2O
CH4
Pesticides
Farm input and output
Nutrient use
Energy use
Water use
Health and welfare
Animal welfare and health Husbandry
Nutrition
Health
Quality of produced food Pesticide residues
Nitrate
Mycotoxins
Heavy metals
Desirable substances
2.3.3 Terms of reference
With the decision to analyse the environmental and resource use impacts of
organic and conventional farming on the basis of environmental indicators, the
12
next question to be answered is of how to correctly present the analysed
environmental indicator data.
The most relevant way to present data on environmental indicators is to relate
this data to:
a) the input (e.g. energy use per hectare land area), or to
b) the output (e.g. energy use per ton of wheat produced) of a farming system.
Relating data to the output takes the productivity of a farming system into
consideration. If two systems differ in their productivity, the analysis of an
environmental indicator leads to different results for the input and the output.
This fact often causes some confusion about the results of an indicator analysis,
its interpretation and its relevance.
To relate an environmental indicator to the land area makes sense in those cases
in which the decision has been taken to maintain a stable agricultural land area.
The only question is whether to farm it organically or conventionally. On the
other hand, it is appropriate to relate an environmental indicator to the output if
the quantity of food to be produced is set, while farmland is variable. In this
case the productivity is the important factor. Output results can change
depending on the assumed level of productivity and the potential of
productivity. An interpretation of the per unit of output approach could be a
difficult task as it would also have to consider whether a change in the
agricultural land area has positive or negative effects on the environment and
the resource use.
In terms of informed policy decision, it would be desirable to relate information
to both the input and to the output. However, working with secondary data
implies that many studies do not provide complete information. In most cases,
though, data on an environmental indicator is only available on the input, the
per unit of land area basis. Although in scientific terms it is deplorable that most
information is not available on a per unit of output basis, this is less problematic
for today’s practical EU policy. Food surpluses are more of a problem in the
current political environment than food scarcity and there seems to be a broad
consensus to keep the amount of farmland relatively stable. Therefore, in the
EU, in most cases, the policy relevant way is to apply the data on environmental
indicators to the input on a the per unit of land area term.
13
2.3.4 Aggregation of information
In order to improve the policy relevance of the results, it is necessary to
aggregate the indicators analysed to one final result, e.g. a sustainability index.
Data aggregation currently faces the fact that there is no commonly accepted
methodology to alleviate the problem of evaluating and summarising the
environmental indicator data.
For this study, we have chosen a step by step qualitative assessment approach
for data aggregation. First, each parameter of an environmental indicator is
analysed on the basis of secondary material. We then present the results of the
studies reviewed on a detailed level. Subsequently, we aggregate the parameter
results by indicators. The review of each indicator ends with a qualitative
assessment of the respective indicator sub-category evaluated on a scale that
rates the environmental and resource effects of organic farming in comparison
to conventional farming (see Table 2-3). These results will finally feed into a
qualitative assessment scheme in which we aggregate the indicators of each
section according to indicator category. The assessment schemes applied could
be described as a multi-criteria analysis based on the authors' expert knowledge.
Because of the subjective element involved, we try to keep this part as
transparent as possible. Thus, the reader will be able to follow exactly how the
authors reach their conclusions.
The assessment takes a conservative approach. We assume no differences
between organic and conventional farming unless research results provide clear
evidence that such a difference exists. This implies that if the assessment
scheme shows no difference between the farming systems, there could be the
following two reasons for this:
a) it could be that research provides distinct evidence of no differences for an
indicator or its category; or
b) that the research reviewed is insufficient from our point of view and that no
final conclusion can be drawn.
Additionally, each indicator assessment will also provide the entirety of the
information involved that has been aggregated to one single assessment on the
scale shown in Table 2-3.
14
Table 2-3: Assessment scale used for indicator evaluation
Scale Organic farming performs...
+ + = much better
+ = better
o = the same
= worse
– – = much worse
... than conventional farming
As the interpretation of data in some cases is quite definite, while, in other
cases, a wider range of assessments seems possible, the qualitative assessment
scheme is complemented by providing a subjective confidence interval for each
indicator. This subjective confidence interval is the result of critical discussion
among the authors with respect to the possible margins of error of the
assessment made.
Due to the fact that research studies applying environmental indicator data to
output are scarce, the conclusions illustrated in the qualitative assessment
scheme summarise our results for the input on a per hectare basis.
To summarise the methodological challenge: The data availability on
environmental indicators is much less than ideal. Because of this, this report
uses a rather broad classification of systems (organic vs. conventional) for
comparison. The conclusions are scientifically found, but they are less precise
and differentiated than we would wish them to be. Because of the above
mentioned imprecision, the results can only be of a qualitative nature. In order
to improve the policy relevance of the results gained, we aggregated the results
by indicator categories following a qualitative assessment approach based on
transparent subjective judgement.
Despite the shortcomings outlined, we believe that it is possible to draw general
conclusions useful for policy purposes. The alternative would be to wait for the
results of a major, co-ordinated European research effort before any statements
are made. We would welcome such an effort and this study can also be regarded
as a part of preparing for it. It is necessary, however, to review and evaluate
current scientific knowledge since practical policy can not wait.
15
3 Definitions and standards of organic
farming in relation to environment and
resource use
Within the European Union, organic farming can be defined as a system of
managing agricultural holdings that implies major restrictions on fertilisers and
pesticides. This method of production is based on varied crop farming practices,
it is concerned with protecting the environment and seeks to promote
sustainable agricultural development.
It pursues a number of aims, such as the production of products which contain
no chemical residues, the development of environmentally sensitive production
methods which avoid the use of artificial chemical pesticides and fertilisers, and
the application of production techniques that restore and maintain soil fertility.
Inspections are carried out at all stages of production and marketing, with a
compulsory scheme, officially recognised and supervised by the EU-member
states, involving regular checks on all operators (Baillieux and Scharpe 1994).
To the maximum extent feasible, organic farming systems rely on crop
rotations, crop residues, animal manure, legumes, green manure, off-farm
organic wastes, and measures of biological pest control to maintain soil
productivity and tilth, to supply plant nutrients and to control insects, weeds and
other pests. Therefore, organic farming is best defined by its principal
ideological background based on the concept of the farm as an organism in
which all components - soil, plant and animals - interact to maintain a stable
whole (Lampkin et al. 1999).
A farming system based on these definitions and their accompanying measures
claims to be more environmentally sensitive and to have less harmful effects
than conventional farming. However, the most obvious factor distinguishing
organic farming from other approaches to farming is the existence of both
legislated and voluntary standards, as well as certification procedures to provide
a clear division between organic and other farming systems.
The objective of this section is to provide an overview of the basic definitions
of organic farming relevant to existing bodies and to discuss how this definition
is implemented by different organic farming standards with respect to the
environmental factors discussed in the following chapters. On this basis, a
review of recent scientific investigations of the environmental effects of organic
farming in comparison to conventional farming will then provide a realistic
picture of the contribution of organic farming to an environmentally sensitive
and sustainable use of resources.
16
3.1 International standards
3.1.1 IFOAM
The implementation of the definition of organic farming is based on the ‘Basic
Standards for Organic Agriculture and Processing’ of the International
Federation of Organic Agriculture Movements (IFOAM).
These basic standards provide a framework for certification programmes world
wide to develop their own national or regional standards. These need to take
local conditions into account and tend to be stricter than the IFOAM Basic
Standards, which cannot soley be used for certification. Any product sold as
organic must have been produced within and be certified by a national or
regional certification programme in accordance with the IFOAM Basic
Standards. All national and regional certification organisations must comply
with existing legislation.
The key characteristics of organic farming have been considered in the
regulations of the IFOAM Basic Standards. These usually consist of three levels
of ‘regulations’:
1. minimum requirements or restrictions which exclude the use of certain
substances or practices;
2. general rules describing necessary practices in general, or demanding more
detailed rules by certifying bodies which outline strategies of avoidance and
preventive measures; and
3. recommendations of how to achieve the objectives of these general rules.
The key points of organic farming outlined in the IFOAM standards are the
following:
a) the increase, or at least maintenance of soil fertility on a long-term basis;
b) the exclusion of Chilean nitrate and all synthetic nitrogenous fertilisers,
including urea;
c) the exclusion of synthetic pesticides;
d) the definition by national and regional certifying bodies of maximum total
and outdoor stocking densities;
e) the regulation of animal husbandry according to the physiological and basic
ethological needs of the farm animals in question in order to ensure
maximum animal welfare; and
f) the exclusion of synthetic feed additives, such as growth-promoters and
hormones.
Maintaining or increasing fertility on a long-term basis is to be achieved by:
returning sufficient quantities of organic material to the soil;
increasing or maintaining biological activity;
only introducing material which is specified for use in organic farming;
17
providing restrictions by certification bodies for the use of inputs which
contain relatively high contents of unwanted substances so as to maintain the
natural conditions of the soil with respect to, for example, pH values and
heavy metal contents;
having requirements declared by certifying bodies for the rotation of non-
perennial crops in a manner that maintains or increases soil, organic matter,
fertility, microbial activity and general soil health; and
recommending that the certification programmes insist upon specific
rotations, including legumes.
The exclusion of Chilean nitrate and all synthetic nitrogenous fertilisers,
including urea, calls for the following:
an avoidance of undesired inputs, i.e. by clear distinction between
neighbouring organic and conventional fields, and by respecting a
conversion period;
only a supplementary use of mineral fertiliser (e.g. P, K, rock-powders for
micro-nutrient supply) to organic fertilisation;
the use of species and varieties, which are adapted to the soil and climatic
conditions to the maximum extent possible in order to limit the necessity of
fertilisation; and
an insistence on diverse crop rotations with an inclusion of legumes by
certification programmes.
The ban of synthetic herbicides, fungicides, insecticides, and other pesticides is
to be supported by following additional measures:
maximum avoidance of undesired inputs from outside (i.e. contamination of
equipment, conversion period, distinction of neighbouring fields, etc.);
all measures to avoid losses from pests, diseases and weeds (crop rotations,
manure programmes, etc.); and
the use of the recommended physical and thermic measures of crop
protection, i.e. pheromone traps or thermic weed control.
18
The maximum total and outdoor stocking densities must be limited by national
and regional certification bodies. This is supported by the limitation of fodder
imported from outside the farm, which must also be specified by national and
regional certification bodies.
Maximum animal welfare is to be ensured by providing sufficient free
movement, fresh air and natural daylight, fresh water and feed, protection
against weather conditions, and enough lying and resting area with natural
bedding material according to the need of the animals. Clear rules are set for
indoor housing conditions, i.e. poultry shall not be kept in cages, or that a
maximum number of hours of artificial lighting has to defined by national
organisations. Breeding goals shall secure natural birth, i.e. embryo transfer
techniques and the use of genetically engineered species or breeds is not
allowed. Furthermore, mutilations must be avoided.
For animal nutrition, the maximum percentage of feed from conventional
farming systems and access to roughage is defined. The prohibition of synthetic
feed additives, such as growth-promoters, hormones, and the prophylactic use
of allopathic medicines is accompanied by the recommendation to direct all
management practices to maximum resistance to diseases and to prevent
infection. Even vaccinations are only approved by the certification programmes
when no other form of management technique can control the respective
disease. However, the use of allopathic drugs is allowed in the case of illness
when no other justifiable alternative is available. The well-being of the animal
is more important than the choice of treatment. Therefore, withholding periods
are specified to be at least double the legal periods. All other standards for feed
and feed ingredients must be defined by certification programmes.
3.1.2 European Union
In the European Union, organic farming is implemented, labelled, controlled
and marketed according to EC Reg. 2092/91 and its updates. Within the
European Union, IFOAM Basic Standards are replaced by EC Reg. 2092/91.
Thus, EC Reg. 2092/91 provides a framework for organic farming within the
EU based on subsidiary principle and its implementation. It is to a certain extent
flexible with respect to adaptation, supplementation, and precision of technical
details in respect to national conditions.
In comparison to IFOAM Basic Standards, EU regulation of plant production
does not cover as many production areas. Animal husbandry and pollution
control, soil and water conservation, storage and transportation of products,
packaging and social justice are some of these. Instead of providing a wide
range of diverse recommendations and regulations, the EU standards are based
on a few fundamental regulations that focus on avoiding the use of fertilisers
and pesticides and only permit
19
the use of certain specified fertilisers and substances for crop protection. The
list of specified substances does not differ substantially from the IFOAM list of
substances. Human excrement, sewage sludge, and urban compost - although
restricted in their use – are allowed by IFOAM Basic Standards. According to
the EC Reg., however, the use of these substances is entirely prohibited. EC
Reg. 2092/91 permits the use of clays for fertilisation and with a special permit,
sulphur, trace elements and potassium sulphate as well.
As EC Reg. 2092/91 did not provide standards for organic animal husbandry
until August 1999, some countries, i.e., Sweden’s KRAV (1997), have based
their animal husbandry standards on the IFOAM Basic Standards, whereas in
other countries the production standards of national certifying organisations are
of more importance. In August 1999 uniform minimum standards for organic
animal production (EC Reg. 1804/99) were passed as an expansion to EC. Reg.
2092/91. Their central elements are the limitation of livestock density, the
limitation of feed brought in from outside the farm, and the exact definition of
minimum housing and outside area per animal. Furthermore, tied-stall
husbandry for ruminants and cage keeping of poultry is forbidden, as well as the
use of GMO.
Some elements of this recently introduced regulation for organic animal
husbandry exceed the national standards of some countries, i.e. the exact
definition of minimum housing area is less specific in Germany (AGÖL 1996).
EC Reg.1894/99, however, permits the use of nearly all types of conventional
feed within a given percentage of the total. This is more restricted by AGÖL
(1996) in Germany. Again, the national governments need to adapt this
regulation according to country specific situations, and create a range of diverse
production environments within a common legal frame.
3.2 National Regulations
National organic farmers’ associations establish their own standards, based
upon the standards of IFOAM and EC Reg. 2092/91. The final form and
coverage of these national standards may differ widely among countries. Some
only pick up the requirements of IFOAM, others work in accordance with EC
Reg. 2092/91. Spain and Portugal (CRAE 1994, AGROBIO 1988), have
established their own production standards (CRAE 1994, AGROBIO 1988).
Germany and Denmark (AGÖL 1996; LØJ 1996) have designed their own
production standards. National standards often cover even more areas than the
IFOAM standards. Sweden (KRAV) has declared standards for restaurants,
industrial kitchens and pet food.
National regulations tend to be more specific than IFOAM standards or EC Reg.
2092/91 with respect to soil fertility. Bioland Germany states that rotations must
include legumes, whereas Biopark Germany has set a clear
20
minimum standard of 20% green manure within the crop rotation at any point of
time (Bioland 1997; Biopark 1996). The Soil Association UK (1997) requires
regular inputs of organic residues in the form of manure and plant remains and
recommends maintaining a protective covering of vegetation of, for example,
green manure or growing crops. In Sweden, KRAV gives upper limits of heavy
metal contamination independently of what is applied to the soil. Industrial by-
products - although allowed - must be analysed if any doubts arise about
contamination. Topsoil can be imported to the farm if it comes from non-
contaminated sites. Demeter in Germany and Luxembourg state that the natural
soil pH must be maintained at all times (Demeter Germany 1995, Demeter
Luxembourg 1997).
All national bodies are required to follow IFOAM Basic Standards in regard to
the ban on synthetic N-fertilisers, etc. However, different certifying bodies have
provided their own list of substances permitted for fertilisation. The use of
human excrement, sewage sludge and urban compost is only permitted in some
countries, i.e., by KRAV in Sweden, provided that the natural status of the soil
is maintained. On the other hand, KRAV does not permit the use of guano. In
Denmark, LØJ permits the use of separately collected human urine and wastes
from the food industry, although human excrement as a whole is not allowed
(LØJ 1996). In other countries, such as the UK and Germany, (Soil Association,
Bioland, Demeter) these substances are not specified in the list of fertilisers that
may be used.
A wide range of substances is permitted for alternative crop production. For
example, LØJ, Denmark is the only certifying body reviewed so far that
provides maximum concentrations of solutions of sulphur, soft soap and mineral
oils. Furthermore, several substances permitted by IFOAM and EU standards
are not allowed, such as pyrethrum, copper salts, chloride of lime and soda, or
microbial pest controllers. Spain (CRAE 1994) stands on the other end of the
spectrum with their exclusive focus on the EC Reg. 2092/91.
Strategies to prevent contamination by pesticides are specified quite differently
in national regulations. The maximum percentage of fodder brought in from
other organic farms and conventional farms must not exceed 10-50% and 5-
15% i.e. for ruminants, respectively (KRAV; Soil Association; AMAB, Italy
1997) in order to avoid undesired inputs of pesticides to organic animal
produce.
Definition of maximum stocking density is one of the obligations of each
national or regional controlling body put forward by IFOAM. This may range
from 1.4 LU/ha to 2.0 LU in Denmark and Germany, respectively.
21
Details on requirements for animal husbandry with respect to animal welfare
differ widely. Bioland, Germany and the Soil Association, UK provide detailed
housing and grazing requirements for various animals, whereas KRAV only
specifies space requirements for hens.
The use of synthetic feed additives etc. is completely banned by all certifying
organisations, as demanded by the IFOAM standards. The therapeutic use of
allopathic medicines can not be banned completely at this point. However,
retaining periods given by national organisations range from one to three times
the legal retaining period (Biopark, Germany and Soil Association, UK or LØJ,
Denmark, respectively).
From an overall perspective the country specific regulative environments in the
EU are diverse, although in the future this range will be somewhat more limited
due to the tightening of the common framework after the introduction of the EU
livestock regulation in August 1999. However, due to climatic and structural
differences among the countries, organic farming in Europe will remain
characterised by diversity.
3.3 Summary and Conclusions
In general, organic farming is best defined by considering the farm or the
agricultural production unit respectively as an organism in which all
components – soil, plants and animals - interact to maintain a stable whole
(Lampkin et al. 1998). All organic farming organisations world wide operate
within the IFOAM Basic Standards, which provide the basic principles.
Certifying organisations implement these basic standards according to specific
national conditions. Thus, the farming system is being regulated world wide on
a common basis, whereas production itself is only outlined in certain parts.
National certifying organisations must specify details of the production methods
in their standards. As long as production is practised within this defined range
of action, all other farming activities are intrinsic to the organic farming
definition and need not be specified in complete detail. This hierarchy of
regulations among IFOAM and the national certifying bodies provides a
common denomination, while maintaining certain aspects of national identity
and permitting adoption to local conditions.
Within the European Union, EC Reg. 2092/91 provides the determining
standard for organic farming. Again, specific national conditions can be
accounted for in each country within this framework. Instead of providing a
wide range of recommendations and regulations, the EU standards are based on
a few basic rules and orders, which focus on avoiding the use of fertilisers and
pesticides and permitting only the use of certain specified fertilisers and
substances for crop protection. Comparable national or international definitions
and regulations exists neither for conventional nor for integrated farming
systems as it does for organic farming.
It is important to keep in mind that organic farming standards use two methods
to achieve the desired environmental results:
1. the regulation of the use of inputs in order to attain an environmentally
sensitive system; and
22
2. the requirement of specific measures to be applied or, in some cases, of
specific environmental or resource use outcomes.
In general, the first method is of more importance. The second is more of a
supplement. This is especially true in crop production, where the Driving force
farm input is evaluated by the standards. However, on a national level, there
seems to be a tendency to give more weight to the requirement of specific
measures and outcomes than on the international level. The designing of
national standards and the implementation of EC RE. 2092/91, which allow a
certain margin of adoption to nation conditions, can lead to discrepancies in the
regulative environments and the competitiveness of organic farms in the various
EU countries.
23
4 Impacts of organic farming on the
environment and resource use
This section forms the core of this report: The empirical evidence for each
indicator described in Table 2-2 is reviewed. Currently, only few
comprehensive research projects on environmental and resource use impacts
have been set up. The most important studies in this context are the DOC trial
(comparing biodynamic, bio-organic and conventional systems) and the Pilot
Farm Network, both conducted in Switzerland. The Pilot Farm Network aims at
developing farming systems economically, ecologically and technically. It
evaluated about 110 organic, integrated and conventional farms between 1991
and 1996 (Hausheer et al. 1998). While the pilot farm network follows a more
dynamical approach, the DOC trial focused more on the current state of farming
systems. First conducted over 14 years ago, the DOC trial helps investigate
differences in biodynamic, bio-organic, conventional/integrated systems, each
in a rotation with special focus on biodiversity and soil fertility. Apart from
these projects, most research results presented below represent more or less
individual results with individual character. Several authors (e.g. Haas and
Köpke 1994; Piorr and Werner 1998; Unwin et al. 1995) made efforts to review
research results on a national scale. The studies mentioned above represent the
most important ones in the subject at the moment, and are therefore cited
frequently.
4.1 Ecosystem
Since its beginnings, agriculture has been a source of positive and negative
effects on the ecosystem in terms of wildlife conservation and landscape.
Ecologists agree that modern agriculture has, during the last decades in wide
areas of Europe, reached a level of intensity resulting in a negative development
of biological diversity of domestic and wildlife species. This has made
important characteristics of the landscape vanish. The most important reason for
the decreasing biodiversity is the destruction of biotopes (SRU 1996). Both the
simplification of crop rotations and the increasing input of agro-technics,
synthetic fertilisers and pesticides have been responsible for the fact that
agriculture has become one of the main sources for changes in the habitat of
many floral and faunal species (Knauer 1993).
Organic farming’s impact on wildlife conservation and landscape is reviewed
for the following indicator subcategories: species, diversity (floral and faunal),
habitat diversity and landscape.
4.1.1 Species diversity
There are three relevant levels at which developments of species take place
according to a widely used definition of biodiversity (OECD 1997):
diversity within a species (genetic level);
Gelöscht:
b
io-dynami
c
Gelöscht: bio-dynami
c
24
changes in the number of species and their population (species level); and
changes in natural habitats providing the necessary conditions for
populations of species (ecosystem level).
The OECD (1997) addresses biodiversity in agriculture and proposes to
consider both domesticated and wild species. The diversity of varieties of crops
and livestock breeds, the breadth of the genetic base and the state and trend in
the genetic reservoir are the suggested indicators to measure biodiversity on
domesticated species. Besides focusing on the number and population of
wildlife species, key indicator wildlife species which are representative for
certain habitats or are endangered or threatened respectively can be used
(OECD 1997).
4.1.1.1 Floral diversity
According to the OECD's proposition, this section will consider floral diversity
of both domestic and wild species.
As far as biodiversity of domestic floral species is concerned, research results
concentrate on measuring the parameters crop rotation diversity, number of
cultivated crops and grassland composition. Hausheer et al. (1998), evaluated
crop rotations on 110 organic, integrated and conventional farms in a Swiss
pilot farm project and determined the following situations on organic farms.
More diverse rotations with more crops
average for organic farms: 4.5 different crops
average for integrated farms: 3.4 crops, and
A higher number of crops, including perennials, vegetables, and herbs
average of organic and integrated farms: 10.2 crops
average conventional farms: 7.4 crops.
Furthermore, the analysis of 317 Swiss organic arable farms showed that 75.7%
of the farms cultivated more than six crops, while 87.5% cultivated more than 4
crops in their rotation (Freyer 1997). A 14% higher diversity of organic arable
land use after conversion is calculated for Brandenburg, Germany, using the
Shannon index (Piorr, H.P. et al. 1997).
In permanent crops a higher species diversity can be attained by applying a
cover crop rotation for weed control. This is reported for organic olive
production (Kabourakis 1996).
The composition of organic grassland on 10 organic dairy farms showed
increasing diversity of broad-leaved species such as Ranunculus, Taraxacum
and Urtica at the expense of Lolium perenne during conversion (Hagger and
Padel 1996).
Younie and Amstrong (1995) found a higher proportion of Lolium perenne and
Trifolium repens comprising 95% of the sward on organic farms, as well as
conventional grassland swards that were sown 7-9 years earlier. There was a
higher presence of clover in the organic system. Conversion did not increase the
species composition in grassland per se or in the short-term, even though a
higher incidence of Bellis perenne and Ranunculus species was found in the
final year of the survey on the organic fields. Investigations on about 100
25
organic grassland sites also showed that floral diversity decreases significantly
with increasing productivity of grassland as a result of a higher proportion of
white clover (Wachendorf and Taube 1996).
The northern European countries emphasise that it is very important for wildlife
biodiversity that animals graze on unfertilised natural pastures. For example,
grassland fungi as indicator species for diversity find better conditions for
survival in extensive organic systems. Even endangered species are present if
grassland composition is not influenced by fertilisation and plant growth limited
by grazing (Jordal and Garder 1995). Nevertheless, organic fertilising can also
reduce the number of herbs by half and incorrect organic fertilising strategies
can have negative effects on biodiversity (Svensson and Ingelög 1990).
For wildlife floral species, research results are based mainly on the analysis of
botanical composition, amount of species, occurrence of endangered species
and on the frequency of certain floral species on arable land and grassland.
Several authors found up to 6 times more species on organic arable land or
grassland than on conventional ones (Ammer et al. 1988; Frieben 1997; Hald
and Reddersen 1990; Mela 1988; Rasmussen and Haas 1984; Vereijken 1985).
As far as endangered species are concerned, Cobb et al. (1998) and Frieben
(1997) found a higher presence (50 - 80%) of one or more endangered species
on organic farms, in comparison to 15 - 30% on conventional fields. Generally,
ADAS (1998) and Mela (1988) stated that organic farms show a more diverse
botanical composition and more botanical families.
As farming systems not only influence the cultivated area but also the
neighbouring sites, i.e. field edge strips and hedgerows, these were also
examined. Preliminary results from a Finnish study (Aalto 1998) show that
farming systems affect floral species on field edge strips. Although these effects
are remarkably similar, there are differences in species composition. Field edge
strips next to organically farmed fields showed more blooming vascular plants,
which are insect- or bumblebee pollinated. Furthermore, while floral species
contributed equally to biomass production on organic field edge strips, biomass
production on field edge strips next to
26
conventional fields was dominated by only a few species (Aalto 1998). Another
study reports that the biomass of monocotyledonous weeds was similar in both
farming systems, but that the total biomass of dicotyledonous weeds was
markedly higher (50,1%) in the field edge strips next to organic fields (Holme
1996).
On the whole, the diversity of floral species is closely connected to local site
conditions. In regions with a high potential for biodiversity, organic farming
promotes numerous and highly varied flora. However, in regions with low
potential for biodiversity where certain rare species are traditionally found, the
positive impact of organic farming on wild herb or grassland diversity is less
distinct (Baars et al. 1983; Smeding 1992).
To summarise, there are a number of research results which indicate that
diversity and number of wildlife species is higher on organic than on
conventional fields. However, as far as domesticated species are concerned, the
situation is more complex: There is evidence that organic farms have a higher
diversity of crops in their rotation. This can also be deduced from the major
principles of organic farming, which aim at diversity of domesticated and
wildlife species. Organic farming relies heavily on self-regulation processes of
the production system without applying pesticides and synthetic N-fertilisers.
Therefore, vast crop rotations are essential as a means of disease and pest
prevention, and of maintaining soil fertility by cultivating N-fixing legumes.
Additionally, due to its low intensive production system, organic farming
standards recommend cultivating site-adapted crop varieties. This does not
necessarily mean that organic farming sets narrow limits to modern maximum
yield varieties as they are often chosen for resistance reasons. On the other
hand, the preservation of old land varieties and breeds respectively (especially
in terms of their appropriate breeding) is an important initiative within the
organic farming movement. But this issue depends mainly on the individual
activities of the farmer.
4.1.1.2 Faunal diversity
Research on farming system-dependent livestock diversity could not be
identified in the conducted survey and literature reviews. However,
comprehensive work has been done on wildlife faunal diversity comparing
different farming systems. The parameters applied to measure wildlife faunal
diversity were number, abundance, diversity, distribution and frequency of
species.
Paoletti et al. (1995) counted species in peach orchards (Table 4-1). They found
higher numbers in organic orchards than in conventional ones, especially for
Arachneae, Braconidae, Opiliones and Carabidae. The results for Carabidae
are corroborated by Pfiffner et al. (1995) and Mäder et al. (1996), who were
both in the long-term field experiment of the Swiss DOC-trial, and by Rhône-
Poulenc (1997). On the average 19-22 and 18-24 species, respectively were
found in the organic system, whereas the conventional system had 13-16
Carabidae species (Mäder et al. 1996; Pfiffner et al. 1995). Four times as many
Carabidae were found in organic systems than in conventional ones. On the
whole, a higher abundance of beneficial arthropods was found (Rhône-Poulenc
1997).
27
Table 4-1: Number of species in six peach orchards of two organic and two
conventional farms
Organic 1 Organi c 2 Conventional 1 Conventional 2
Arachneae 49 50 30 29
Carabidae 40 33 28 31
Formicidae 12 13 9 12
Braconidae 910 11
Chilopoda 66 5 6
Isopoda 5 5 4 3
Opiliones 43 1 2
Diplopoda 3 3 0 2
Source: Paoletti et al. 1995
Other investigations on organic farms and fields found:
- a higher diversity and/or a higher frequency of beetles (ground beetles, rove
beetles, ladybirds and others), parasitic Hymenoptera, Diptera, Hemiptera,
spiders, Acarina, Millipede, Crustaceae (Isopoda), Collembolae (several
relevant studies compiled by Pfiffner 1997; also: Krogh 1994; Paoletti et al.
1995; Reddersen 1998); and
- significantly more butterflies and more species in organic fields, but
primarily more in the uncropped boundary habitat than in the cropped edge
habitat (in both systems) (Feber 1998).
Bird surveys have been conducted by the British Trust for Ornithology (BTO
1995) and by Rhône-Poulenc Agriculture (Rhône-Poulenc 1997). The British
Trust for Ornithology compared breeding and wintering of birds on 44 organic
and conventional farms over a period of three years. The study concluded that
breeding densities of sky larks as a key species were significantly higher on
organic farms than on conventional ones (BTO 1995). This result was
corroborated by an intensive follow-up study on a pair of organic and
conventional farms over two years. Generally, higher densities of birds,
especially in winter, were found on the organic farms (BTO 1995).
The data from the BTO study mentioned above has been re-analysed more
recently in connection with data from a Danish study (Chamberlain 1996; Fuller
1997). It concludes that the benefits derived from organic farming systems are
‘whole system’ benefits and greater than those gained from higher levels of
non-cropped areas alone.
In the UK, the Common Bird Census conducted for seven years in a long-term
project by Rhône-Poulenc Agriculture compared organic, integrated and
conventional systems (Rhône-Poulenc 1997). The study showed a steady annual
increase in the number of bird territories on the land converted to organic
production and a higher overall number of territories on the organically
managed land.
The following reasons are mentioned to explain the outcome of the studies cited
above:
28
better breeding and food conditions on organic farms found for key
farmland species (Braae et al. 1988);
a higher number of chick-food insects in organic than in conventional winter
wheat fields (Moreby and Sotherton 1997);
the existence of higher levels of non-crop areas, especially hedges and field
margins, on organic farms (BTO 1995);
a higher diversity of crops on organic farms than on conventional farms,
including rotational grassland and spring cereals, which are likely to provide
high quality breeding habitats for sky larks (BTO 1995); and
more abundant and diverse food sources on the organic sites (BTO 1995).
In contrast, conventional farming can cause mortality in fledglings, as reported
for starlings, due to the use of pesticides and synthetic fertilisers, which cause
unbalanced diets, but also due to the change of the habitat through, for example,
the reduction of ditches and pastures (Tiainen et al. 1989).
ADAS (1998) and Stopes et al. (1995) note the direct impact of farming systems
on cultivated areas and state as well that the extent and management of non-
cropped areas play an important role as a retreat for beneficial organisms, e.g.
”beetle banks”. At Elm Farm Research Centre in the UK, a survey on hedges
during the conversion period showed a 10% increase in the overall richness of
species and a wider range of such in all hedges (Stopes et al. 1995). As far as
field edge strips are concerned, Helenius (1996) found a higher diversity in
organic than in conventional strips in Finland. The genetic level, showed only
49% similar species in organic and conventional edges strips, although the
habitats seemed to be equal. Also, the number of individuals of the dominant
species was higher in conventional field edge strips (29% of all individuals
versus 16% in organic edges). This indicates a higher diversity in the organic
edge strips. The amount of very random species was bigger in organic margins
(27% vs. 17%) (Helenius 1996). Small mammals on uncultivated strips were
surveyed by Rhône-Poulenc: The field edge strips, predator strips and
hedgerows next to organic fields yielded the highest overall levels of trapped
small mammals. Uncultivated hedge areas in the integrated conventional system
produced similar levels (Rhône-Poulenc 1997).
The amount and frequency of all relevant faunal groups was generally found to
be higher on organically cultivated than, or at least similar to, that on
conventional land. In the DOC-trial organic and biodynamic systems were
characterised not only by a higher diversity and abundance (90 % higher than in
the conventional system) but usually by a more balanced species distribution
(Pfiffner and Niggli 1996). Many investigations showed that the variety of both
flora and fauna species as well as the amount of individuals were higher on
organic farms than on conventional farms (Braat and Vereijken 1993;
Kabourakis 1996; Paoletti and Pimentel 1992). On the average, biodiversity is
35% lower in conventional orchards than in organic ones. Single species might
be reduced up to 80% (Paoletti et al. 1995).
A final assessment can conclude that organic farming creates "comparatively
more favourable" conditions on the species and ecosystem level of floral and
faunal diversity than conventional farming systems. This is due to a plant
protection management (ban of synthetic pesticides) that is better for the biotic
Gelöscht: biodynamic
29
system, as well as extensive organic fertilisation, more diversified crop rotation
e.g. higher levels of grass or clover grass leys, and a more structured landscape
with semi-natural habitats (Feber 1998; Mäder et al. 1996).
4.1.2 Habitat diversity
A habitat is defined as a place where organisms of a species are found
periodically, whereas a biotope is a uniform and more or less bordered area
which is the living space of a biocoenosis (ANL 1994). Agricultural land use
generally interferes with wildlife habitats. However, the point of interest in this
study is to identify differences between conventional and organic farming
systems with reference to habitat diversity.
To measure habitat diversity, the OECD (1997) proposes the following
indicators:
changes in selected large scale areas (as woodland, wetlands, pasture);
fragmentation in agro-ecosystems and natural habitats; and
length of contact zone.
30
These indicators were presumably chosen due to measurability and data
logistics. However, they are not appropriate to provide causal links to farm
management practice (OECD 1997). Furthermore, the proposed indicators
assume a high proportion of organic land use, which only applies to organic
farming in a few European regions. For the purpose of this study the following
questions are of interest:
Do organic farmed arable and grassland areas represent special habitats?
Does management practice have particular implications on other habitats?
Is there typical interaction with natural habitats and different forms of
agriculture?
Research results which analyse habitat diversity of farming systems are scarce.
Quantitative data is only provided by Hausheer et al. (1998), who evaluated
pilot farms in Switzerland. They found more ecologically diversified areas on
organic farms. The average number of 4.7 diversifying elements was found on
organic farms in comparison to 3.9 on integrated farms. A significantly higher
proportion of ecologically diversified areas in relation to the total farm land on
organic farms was also determined (Table 4-2).
Table 4-2: The proportion of ecologically diversified land area per farm (%)
Area Organic farms Integrated farms Conven tional farms
Valley 16.0 10.3 3.7
Lower mountain 13.3 15.9 -
Upper mountain 84.0 17.4 -
Source: Hausheer et al. (1998)
Therefore, the habitat diversity of organic farm land is assessed to be higher
than that of integrated farmed land due to a higher diversity of living conditions.
Redman (1992) and Unwin et al. (1995) state that banning synthetic pesticides
on organic farms improves the quality of both crop and non-crop habitats.
Even though habitat diversity is not a specific part of organic standards, organic
management practice has a characteristic impact on habitat diversity, which is
due to:
the ban of chemical additives which equalise site-specific characteristics;
more diverse living conditions on arable land and grassland e.g. for insects
and birds with special nutritional demands;
31
diversified crop rotations (see Chapter 4.1.1); and
contact zones for neighbouring habitats and structural elements of landscape
(hedges, waters) which are protected from nutrient or pesticide drift inputs
and therefore guarantee a particularly low level of nutrient supply (Stachow
1998).
To summarise, there is some evidence that organic farming has a positive
impact on habitat diversity. However, this result is closely related to site-
specific aspects. For example, as a consequence of subsidising conversion on a
per hectare basis, more farms converted in less favoured areas like grassland,
mountain or low-yield regions than in more productive areas (Dabbert and
Braun 1993; Schulze Pals 1994; Stolze 1998). In these regions, habitats such as
woodlands, hedgerows or wetlands etc. might traditionally be established. Thus,
higher habitat diversity observed on organic farms might be due to historical
reasons and not to converting farmers starting to plant hedges or create biotopes
(Clausen and Larsen 1997; Langer 1998). The motive for any form of
agricultural land use is the production of goods. Organic farming cannot ensure
an undisturbed environment, as found in native or wildlife protection areas.
Thus, certain species find no habitat even on organic farms.
4.1.3 Landscape
The definitions of landscape refer to common agro-ecosystems and semi-natural
habitats, as well as to their visual character. In this sense, landscape can be
classified according to its intrinsic beauty, historical features, embodiment of
cultural values, past and present impacts of land use, farm practices,
composition of farming systems, distribution of habitats and man-made features
like stonewalls or historic buildings (OECD 1997). Typical site-specific and
diversified landscapes are of high value for regional identity and have important
social significance.
The OECD continues to discuss appropriate indicator concepts to measure
agricultural impact on landscapes because the value of landscape and the
physical impact of agriculture is often subjective and other sectors contribute to
rural landscapes as well (OECD 1997). Currently, there are two different
indicator approaches based on the following:
estimate of the monetary value of landscapes; and
inventory of physical landscape features.
However, the development of methodology to evaluate landscape quality has
just begun. Quantitative research investigating the impacts of different farming
systems on landscapes could not be identified in this study. Some useful non-
quantitative criteria for describing the influence of single organic farms on rural
landscape quality are suggested by Hendriks et al. (1992):
32
diversity in landscape components (land use, crops, husbandry, humans,
planting, margins, sensorial impressions, age of the elements);
site-related character (relationship to abiotic conditions and specific
features);
cohesion amongst landscape components (functional, spatial, cultural-
historical and social);
historical continuity;
seasonal aspects;
personal participation (visual demonstration of ecological and socio-
economic development);
particularities;
aesthetic values (beauty);
environmental quality (nitrate leaching, mineral balances); and
ecological quality (biodiversity, soil fertility).
Because landscape is always a more or less large scale status of the
environment, the individual farm influence on it is limited. The proportion of
different farming systems within a region determines the land use pattern and
the landscape characteristics.
In order to prevent plant diseases and pests, the shaping of landscape is
supported by some characteristics of organic farm management, such as
diversity of crop rotation and direct measures like planting hedges and creating
biotopes (van Elsen 1997). However, these measures depend on the individual
activity of the farmer. A British study in lowland regions indicates a greater
presence of unmanaged bushy hedges, recent woodland and young and recent
hedgerow trees on mixed organic farms than on conventional farms. But no
differences between the farming systems were found in the more extensively
farmed upland regions and on small horticulture farms (ENTEC 1995). Studies
show that about ¾ of the organic farms in the Netherlands have woody elements
like orchards and hedges (Vereijken and van Almenkerk 1994), and that small
biotopes cover a greater percentage of area on organic than on conventional
farms (Clausen and Larsen 1997). However, the conversion to organic farming
does not presuppose an increase in small biotopes. Thus, in many cases,
observed differences are due to spatial and historical reasons and not necessarily
to the farmers' activities (Clausen and Larsen 1997). Langer (1997) states, that
the changes in agricultural landscapes, affected by organic farming crop pattern
and management, will depend on which type of organic farming the
conventional farms convert to, the extent of conversion, the spatial aggregation
of converting farms and the farm type dominating the local landscape before
conversion.
33
As far as set-aside is concerned, several authors state organic farming provides
a higher potential of biodiversity due to a higher proportion of land set aside
compared with conventional farms (ENTEC 1995; Mäder et al. 1996; Stopes
1995).
Almost all national and private organic standards in the countries investigated
contain statements regarding organic farming’s contribution to landscape
conservation and biodiversity. However, these statements vary from objectives
laid down in the standard's preamble to concrete requirements. The Swedish
control association does not permit the removal of field islands or large ditching
(KRAV 1997). An ecological compensation measure obliges Swiss organic
farmers to leave 5% of their land unfarmed (Schmid 1997).
To summarise: the literature review shows that farming system-specific impacts
on landscapes, individual activities and traditional reasons overlap.
Nevertheless, organic farming provides some potential for positive impacts on
landscape. This conclusion is supported by several authors. Van Elsen (1997)
states that, in spite of many site-specific preconditions limiting the development
potential between farm management and landscape development, the principle
of organic farming provides a perspective for further development of high-
quality landscapes. This includes the possibility of cautious utilisation of
sensitive areas (Noquet et al. 1996), as well as re-qualifying the identity of rural
sites (Pennanzi 1996).
4.1.4 Summary : Ecosystem
The reviewed research results indicate that organic farming provides more
positive effects on wildlife conservation and landscape than conventional
farming systems on a per area unit of land used for agriculture. While data on
faunal and floral diversity allow an unambiguous and positive assessment, the
available information on habitat diversity and landscape can only lead to the
conclusion that organic farming has the potential to provide positive effects.
The main findings are summarised as follows:
floral and faunal biodiversity in organic field margins and neighbouring
biotopes is higher than in conventional ones;
floral and faunal biodiversity of wildlife species on organic arable land and
grassland is higher than on conventional land;
the diversity of cultivated species is higher on organic farms than in
conventional farms;
the organic farming system provides potentials, which lead to positive
effects on wildlife conservation and landscape due to the ban of synthetic N-
fertilisers and synthetic pesticides;
potentially, organic farming leads to a higher diversity of wildlife habitats
due to higher diversified living conditions offering a wide range of housing,
breeding and nutritional supply;
organic farming holds the perspective of re-qualifying rural sites;
34
direct measures for wildlife and biotope conservation depend on the
individual activities of the farmers; and
a deficiency in available research was identified as far as indicators suitable
for measuring habitat diversity and landscape are concerned.
However, the superiority of organic farming with respect to wildlife
conservation and landscape is figured on a per hectare basis of agricultural land.
Chapter 5 provides a discussion whether this is the correct basis of comparison
for policy purposes.
To summarise: it can be stated that organic farming, as well as each form of
agriculture, cannot directly contribute to wildlife conservation targets that
require areas of unspoiled nature, as in the conservation of eagles. However, in
productive areas, organic farming is currently the least detrimental farming
system with respect to wildlife conservation and landscape (Table 4-3).
Table 4-3: Assessment of organic farming's impact on the indicator category
"Ecosystem" compared with conventional farming
+ + + o – –
5
Floral diversity
5
Faunal diversity
5
Habitat diversity
5
Landscape
5
Ecosystem total
Legend: Organic farming performs: ++ much better, + better, o the same, – worse, – –
much worse than conventional farming
5 Subjective confidence interval of the final assessment marked with 5
35
4.2 Natural resources
4.2.1 Soil
Soil is one of the most important natural resources because it is the central basis
for all agricultural activity. Soil conservation is most important as it maintains
the productive capacity of this resource. Environmental effects related to
different uses of soil are equally important.
In order to address agri-environmental issues, the OECD (1997) developed soil
quality indicators within their framework of environmental indicators. These
focus on the following factors of soil damage:
soil erosion;
chemical deterioration (loss of nutrients, soil organic matter, accumulation
of heavy metals); and
physical damage (soil compaction, waterlogging).
Their main objective is to measure the potential risk and state of soil damages
and emphasise aspects such as vulnerability and extent of degradation, rather
than focusing on farming practises which cause these damages to the soil.
Because this study focuses specifically on the impact of two farming systems on
soil, the indicator list was adapted accordingly. It includes the following
parameters:
soil organic matter;
biological activity;
soil structure; and
soil erosion.
The impact of organic farming versus conventional farming will be discussed
based on this extended list of soil parameters. This is an especially pertinent
point because organic farming standards stress the importance of soil fertility.
Analysing the environmental subcategory soil presents the problem that the
indicators used were also suitable to evaluate soil fertility with respect to its
productive potential. The evaluations in this report are not production oriented
but focus rather on organic farming's impact on the environment and resource
use. The environmental relevance represents the background for the following
indicators, and parameters are evaluated as compared to conventional farming
systems.
Gelöscht:
36
4.2.1.1 Soil organic matter
The soil's supply of organic matter plays a central role in the maintenance of
soil fertility. Its environmental relevance is based on the capacity of soil organic
matter to limit physical damage and to improve nutrient availability as well as
biological activity.
Research on soil organic matter concentrates on measuring the parameter of soil
organic carbon content (% Ct ). As the Ct-content is highly soil and site specific,
the dynamics of Ct -content (Ct changes) during conversion are more
informative than absolute data. Besides measuring soil carbon content, results
will be presented on soil carbon conservation, humic substances and microbial
biomass.
Several long-term trials comparing organic farming to conventional farming
have been carried out in various European countries. A summary of relevant
results on soil carbon content and its dynamic is presented in Table 4-4.
Various comparison trials, farm comparisons and on-farm investigations
showed that organically managed soils tend to have higher total soil organic
carbon contents (% Ct) than conventionally farmed arable and horticultural soils
(Armstrong Brown et al. 1993; Labrador et al. 1994; Petersen et al. 1997;
Pomares et al. 1994). Furthermore, in organic plots, soil carbon content either
decreased less (Bachinger 1996; Capriel, 1991; Mäder et al. 1993 and 1995) or
resulted in a more pronounced increase in topsoil and subsoil than in
conventional plots (Diez et al. 1991; Raupp 1995b; Welp 1993). This seems to
apply especially to soils with low organic matter content before conversion
(Løes and Øgaard 1999).
However, in several cases no significant differences were observed in the soil
carbon content of soils on organic and conventional farms (Amman 1989;
König et al. 1989). These contradicting differences might depend on the
stocking density of the respective farms, as was observed by Weiß (1990).
Furthermore, organic farm management practices may induce a temporary
higher decomposition of soil carbon. Special mention must be made here of
mechanical weed control (harrowing), which is used more often and more
intensly in several crops than in conventional farming, because chemical weed
control measures are not permitted.
Long-term investigations support the hypothesis that organic soil management
better conserves soil organic carbon. This is indicated by a higher ratio of soil
microbial biomass to total soil organic carbon and a lower metabolic quotient
(characterising the biomass specific soil respiration) (Mäder et al. 1995). On-
farm investigations also found a higher content of microbial biomass and humic
substances (Labrador et al. 1994; Petersen et al. 1997). The proportion of
organic material and of CO3H in the soil saturation extract was higher in
organic citrus orchards then in conventional ones (Pomares et al. 1994).
Minimum tillage is seen as an important factor of soil organic matter
conservation in permanent crops such as olives (Kabourakis 1996).
37
Table 4-4: Changes of soil organic matter content from initial values in
different farming systems
Country Organic Conventional Remark
Switzerland 1
%Ct 1.53 to 1.68 1.41 comparative trial:
1980-91, differences
already in initial values
Changes -0.11 to –0.13 -0.14
Germany 2,3,4,5
%Ct 0.92 to 1.04 0.79 comparative trial: 1984-90,
medium fertilisation level
Changes -0.01 to –0.02 -0.04
%Ct 1.43 1.22 comparative trial: 1979-1988
Changes +0.15 -0.03
%Ct 1.52 1.30 survey: 1985-87, 5 pairs of
fields; 0-15 cm
Changes -0.05 -0.23
%Ct 1.36 1.36 farm comparison: 1986-92;
1 pair of fields
Changes +0.15 +0.07
Sweden 6
%Ct 2.53 2.51 comparative trial: 1958-1989
Changes +0.09 +0.03
1 Mäder et al. (1993, 1995)
2 Bachinger (1996)
3 Diez et al. (1991)
4 Capriel (1991)
5 Welp (1993)
6 Raupp (1995b)
On the whole, the conducted research review shows that organic farming
provides beneficial effects to the characteristics of soil organic matter. This is
due to organic farming's strong dependence on farm-internal nutrient supply
(except P, K, Ca). Therefore, organic farms base their fertilisation on organic
substances, such as farmyard manure from animal husbandry, compost, green
manure, plant residues and commercial organic N-fertilisers. Consequently,
there is an extensive supply of organic matter passing through aerobic
decomposition processes. Well-balanced management helps meet nutrient
demands and maintain soil organic matter supply as nutrient availability is
provided by the microbial organic matter turnover. Nevertheless, the level of the
soil’s organic matter content, expressed in % Ct, is primarily correlated to the
site-specific
38
conditions such as soil type, texture and precipitation. Different soils have
different intrinsic capabilities to reproduce management effects in more or less
changing Ct contents. The most important farm management elements for
organic matter supply vary in different regions as European organic farm
characteristics differ considerably between climatic zones. Organic farming in
the Northern countries is characterised by a high percentage of leys in crop
rotation because animal husbandry is the dominant farm type. Sustained soil
organic matter content and composition on organic farms in the Mediterranean
countries is based on plant residues and green manure as a consequence of low
stocking densities and the resulting necessity of importing animal manure
(Persson 1994, Pomares et al. 1994, Vizioli 1998).
4.2.1.2 Biological activity
Biological activity is an important indicator of the decomposition of soil organic
matter within the soil. High biological activity promotes metabolism between
soil and plants and is an essential part of sustainable plant production and
fertiliser management. Earthworms, as a key species for soil macro-fauna, are
an appropriate indicator of soil’s biological activities due to their sensitivity to
any kind of soil disturbance. Microbial activity of soils is an indicator of soil
micro-fauna. Both indicators are reviewed below.
Earthworms and meso fauna
Research focusing on the earthworm as a key species investigates earthworm
biomass, abundance, population characteristics and subspecies.
A high supply of organic material from plant residues and manure provides
favourable living conditions for earthworms and other fauna in soils. A
synthesis of relevant scientific results by Pfiffner et al. (1997), comparing
organic and conventional farming systems, concluded that the following
generally occurred:
a significantly higher biomass and abundance of earthworms;
a significantly higher diversity of earthworm species; and
changes of population composition, indicated by more anecic and juvenile
earthworms in organically farmed soils (Alföldi 1995; Bauchhenss 1991;
Bauchhenss and Herr 1986; Braat and Vereijken 1993; Christensen and
Mather 1997; Gehlen 1987; Mäder et. al. 1996; Maidl et al. 1988; Necker
1989; Paoletti et al. 1995; Pfiffner 1993; Pfiffner and Mäder 1997;
Sommagio et al. 1997).
This is probably due to the fact that organic farming depends more on a high,
sustained supply of organic substance from plant residues and manure than
conventional farming which can rely at least partly on the
39
mineral supply of nutrients. The inclusion of grass leys, preferably of several
years (>2 years), into farming systems seems to be of special importance with
respect to earthworm mass (Neale 1998; Rhône-Poulenc 1997; Scullion 1998).
Organic farming systems rely more on mechanical weed control and in certain
crops on considerably more intensive soil tillage as the use of synthetic
herbicides is prohibited. This can have negative effects on other key species of
soil meso-fauna, i.e. a reduction of population of Collembola with organic
cultivation (Krogh 1994).
Soil microbial activity
The parameters for characterising soil microbial activity used in the reviewed
research results are total microbial biomass, diverse enzymatic parameters,
carbon turnover parameters and mycorrhization.
All relevant comparative trials and on-farm investigations conducted either to
observe soil processes after conversion or to improve plant nutrition strategies
found:
an improvement of microbial activity correlated with the period the soils
were farmed organically;
a 20-30% higher microbial biomass than in the conventional systems
(Alföldi 1995, Mäder et. al. 1996);
a 30-100% higher microbial activity in organic plots in comparison to
conventional plots (Beck 1991; Diez et al. 1985; Niederbudde and Flessa
1988), with a particularly positive impact of biodynamic treatments (Mäder
1997);
higher microbial diversity in organic plots than in conventional (Fliessbach
1998; Fliessbach and Mäder 1997);
higher efficiency in organic carbon turnover in organic plots (Mäder et al.
1995);
organic plots showed a more efficient use of available resources by soil
organisms as indicated by a lower metabolic quotient for CO2 and a higher
incorporation of 14C labelled plant material than conventional plots
(Fliessbach 1998; Fliessbach and Mäder 1998);
higher mycorrhization in soil under organic than conventional winter-wheat,
cover crops (vetch-pea-rye mixture) and clover-grass (Mäder 1997; Mäder
et al. 1993);
a higher level of mycorrhizal infection and spores in organic than in
conventional grassland soils (Scott et al. 1996); and
a higher number and abundance of saprophytic soil fungi with a higher
potential of decomposition of organic material (Elmholt 1996; Elmholt and
Kjøller 1989).
The results of one long-term investigation are listed as an example in detail in
Table 4-5. The positive effect of the organic treatments was observed for almost
all parameters of microbial activity.
Gelöscht: mycorrhisa
40
Table 4-5: Soil microbiological properties after 12 years of farming - relative
results to conventional (=100%), DOC-trial
Parameter Control1 Organic Conventional2 Mineral3
Biomass (SIR) 78 117 – 134 100 82
Biomass (ATP) 94 110 – 125 100 95
Dehydrogenase 68 135 – 158 100 80
Catalase 88 121 – 130 100 91
Protease 58 134 – 168 100 87
Alcaline phosphatase 48 155 – 233 100 87
Saccharase 75 117 – 135 100 94
C-mineralisation 93 108 – 112 100 96
N-mineralisation 92 95 – 98 100 91
Metabolic quotient 123 82 – 92 100 117
Decomposition of cellulose
Laboratory 80 85 – 89 100 105
Field 65 62 – 81 100 87
Mycorrhiza 208 130 – 139 100 95
Source: Mäder et al. 1995
1 zero fertilisation
2 organic and mineral fertilisation
3 mineral fertilisation only
However, as the level of biological activity changes very slowly in response to
varying fertilisation levels and cultivation techniques, no differences in
microbial activity between organic and conventional plots were observed in
several on-farm investigations (König et al. 1989, Maidl et al. 1988, Necker et
al. 1992). Any experiment trying to assess these changes requires 8-10 years of
post-conversion farming (Peeters and van Bol 1993; Rinne et al. 1993).
To summarise: the reviewed research results lead to the conclusion that with
respect to the environmental indicator "soil activity", organic farming clearly
performs better than conventional farming. The main reason for this is that
organic farming aims at organic fertilising management based on crop rotations
with clover/grass ley, underseeds, catch crops, green and animal manure.
41
4.2.1.3 Soil structure
The environmental significance of favourable soil structure lies in an improved
resistance to structural soil damage, such as compaction and erosion. Soil
structure can be measured by a diverse number of physical parameters, such as
the stability of aggregates, coarse pores, air capacity and water holding capacity.
Maidl et al. (1988) and García et al. (1994) found a higher aggregate stability in
organic than in conventional soils. This is a result of more phases of soil
recreation, rotations including clover grass, application of organic manure and
flat tillage. On the other hand, several research studies (Diez et al. 1991; Gehlen
1987; König et al. 1989; Petersen et al. 1997) found no differences in the
aggregate stability of organically and conventionally managed soils.
A higher percentage of coarse pores on organically farmed soil than in
conventionally farmed soils were found by Niederbudde and Flessa (1989).
Research results by Diez et al. (1991) showed that compared with
conventionally managed soils, the air capacity in the topsoil of organic farms
tended to be higher, while it was lower in the subsoil. This can partly be due to
compaction resulting from several years of clover grass cultivation with
frequent passing of tractors. Also, negative results of a higher soil penetration
resistance was found by Maidl et al. (1988) although no differences between the
farming systems were found as far as water holding capacity is concerned (Diez
et al. 1991).
However, in most relevant long-term trials, no differences in soil physical
parameters between organic and conventional farming systems could be
observed (Alföldi et al. 1993; Meuser 1989; Niggli et al. 1995). Even after 14
years, no difference in total and macro pore volume, bulk density, and soil
stability was observed and no positive correlation of soil biological parameters
and physical parameters was detectable (Alföldi et al. 1993). In almost all other
cases a positive effect of organic farming on soil structure could not be
confirmed, and, if at all, only for topsoil (Maidl et al. 1988). A significantly
improved soil structure was only observed when soils were managed
organically for decades (Malinen 1987). Therefore, on-farm investigations often
cannot find any differences between the farming systems with respect to soil
structure.
In organic farming systems, plant growth results from good rooting conditions,
which, in turn, depends on the spatial and chemical availability of nutrients
resulting from microbial activity and the exchange of water and air. Thus,
favourable soil structure is of higher importance in organic farming systems
than in conventional ones. The research results reviewed showed no distinct
differences between the farming systems. An improvement in soil structure can
only be observed after decades of farming organically.
4.2.1.4 Erosion
Soil erosion by wind and water is a world wide problem (Pimentel et al. 1995).
It is assumed that erosion is the main cause of soil degradation around the world
(Oldeman, 1994). The effects of soil erosion occur on eroded fields (on-site
effects) and downstream (off-site effects). On-site effects include the loss of
fertile topsoil and changes soil water dynamics, nutrient status, soil organic
42
matter characteristics, soil organisms and soil depth, and thus result in lower
yield capacity. The off-site effects are mainly undesired nutrient, pesticide and
sediment inputs to surface waters. Although erosion partly depends on site
specific risk factors, such as topography and climate, the extent of damages by
soil erosion can be limited by farm management practices.
There are diverse indicators to measure the risk of soil erosion on different sites.
The main interest of this study are the effects of the farming system,
independent of site-specific risk. It focuses on the indicator agricultural
measures, as expressed in the cropping factor of the Universal Soil Loss
Equation (USLE).
Hausheer et al. (1998) developed a ”soil protection index” of selected
parameters of soil erosion risk. Investigations of organic and integrated farms in
comparison to conventional farms found a higher soil protection index on
organic and integrated farms in 80% and 85% of the cases respectively than on
conventional farms within only one year. There were more organic than
integrated farms with a very high soil protection index. This soil erosion
controlling potential of organic farming is due to:
diverse crop rotations with a high percentage of fodder legumes;
a high percentage of intercrops and underseeds, both aiming at year round
soil cover;
fewer row crops (e.g. sugar beet, maize); and
a sustained supply of stable manure, resulting in higher soil intrinsic stability
due to higher stability of aggregates and more biopores etc. (Arden-Clarke
1987; Auerswald 1997; Dabbert and Piorr 1998; Kerkhoff 1996; Piorr and
Werner 1998; Pommer 1992; Unwin et al. 1995).
In permanent crops such as apples, citrus fruits or olives, the risk of erosion is
usually reduced by vegetation cover and minimum tillage with a low frequency
in soil disturbance (Kabourakis 1996, Pajarón et al. 1996).
However, in organic crop production, the following factors might increase the
risk of erosion in comparison to conventional systems:
frequent soil disturbance by mechanical tillage;
wider row distances when seeding cereals;
slower juvenile development of the crops due to lower N-availability; and
premature breakdown of crops due to diseases (Auerswald 1997).
In total, these factors seem to contribute less to the erosion potential than the
soil conserving factors mentioned above, as shown by calculations from
comparative farm investigations. Usually, organic farming systems are
characterised by a lower C-factor than conventional farming systems. The C-
factor (tillage and coverage factor) describes soil losses at a slope relative to soil
losses at full fallow (Schwertmann et al. 1990) as figured in the Universal Soil
Loss Equation. This is due to the beneficial effects of typical organic crop
rotations. Soil tillage effects remain minor in comparison to these beneficial
effects (Dabbert and Piorr 1998). On the other hand, highly effective soil
erosion minimising measures like direct drilling and mulch-drilling can be
43
found more often on conventional farms than on organic farms as these
measures require specific herbicide management.
As more area is needed to produce the same amount of food on an organic in
comparison to a conventional farm, another factor concerning soil erosion must
be noted. The fact that any kind of soil cultivation increases the risk of soil
erosion in comparison to soil covered by natural vegetation could result in
higher erosion potential. However, even though quantitative research results are
somewhat scarce in this area, organic farming comprises a high potential to
reduce soil erosion risk.
4.2.1.5 Summary: Soil
The maintenance and improvement of soil fertility is a central objective of
organic farming, especially since many indirect regulation factors for crop
management are based on a well functioning soil-plant relationship.
The impact of organic farming on soil properties has been covered
comprehensively by research in most aspects. Information is somewhat scarce
only with respect to soil erosion. Research shows that organic farming tends to
conserve soil fertility and system stability better than conventional farming
systems:
Organic matter content is usually higher in organically managed soils than in
conventionally managed ones. However, soil organic matter content is
highly site specific.
Organically farmed soils have significantly higher biological activity than
those conventionally farmed.
As far as soil structure is concerned, most research results found no
difference between the farming systems.
Although quantitative research results are scarce, the research review
concluded that organic farming has a high erosion control potential.
Changes in soil fertility are long-term-developments and significant effects
often do not result for 8 years. The assessment of organic farming's impact on
soil is shown in Table 4-6.
Table 4-6: Assessment of organic farming's impact on the indicator
subcategory "Soil" compared with conventional farming
+ + + o – –
5
Soil organic matter
5
Biological activity
5
Structure
5
Erosion
Soil total 5
44
Legend: Organic farming performs: ++ much better, + better, o the same, – worse, – –
much worse than conventional farming
5 Subjective confidence interval of the final assessment marked with 5
4.2.2 Ground and surface water
The protection of ground and surface water has major environmental priority
because any contamination may cause a risk for its use in human and animal
nutrition and may disturb aquatic biocoenosis. The OECD-indicator list (OECD
1997) subsummarises state and risk assessment approaches under this issue. We
will confine our efforts to indicators that are appropriate to evaluate the impact
of different farm management practices.
Detrimental effects of agriculture on ground and surface water are largely due to
erosion and to the leaching or run-off of substances. Erosion has been covered
in section 3.2.1. Phosphate leaching is an issue that is relevant in very few areas
of the EU due to extreme high animal density. Because stocking density in
organic farming is limited, it is highly likely that organic farming does not
contribute to this problem. However, no detailed information was available on
this issue.
In this section, we concentrate on indicators that are appropriate for evaluating
the impact of different farming systems on water quality, such as nitrate
leaching and pesticides.
45
Some of the most important threats to water quality are:
high organic fertilisation level in combination with high stocking rates;
excessive application of mineral N-fertilisers;
lack of protective soil cover;
narrow crop rotation and frequent tillage; and
a high level of available nitrogen after harvest.
4.2.2.1 Nitrate leaching
Groundwater contamination by nitrate leaching from agricultural soils is a
problem in many European areas. In contrast to other undesired environmental
effects, water contamination with nitrate is mainly caused by agriculture. It
occurs when more nitrate is available to the soil than plants can use, when water
from rain, irrigation or snowmelt moves through the soil into the groundwater.
Excessive nitrogen in the soil can be due to fertiliser or manure applications or
nitrogen fixation by leguminous crops. Nitrate in waters can lead to
eutrophication with excessive algal growth and toxic contamination of drinking
water for humans and animals. In the last 15 years, many activities were
undertaken to screen the problem of nitrate leaching and to evaluate measures of
avoidance.
Following is an overview of the most important results from long-term trials,
investigations and net screenings. Comparative long-term trials provide the
most realistic picture of the effects of the risks associated with different farming
systems. On-farm investigations give an overview of the range and permit
conclusions with regard to local characteristics, referring primarily to the state
of an indicator. Net screenings are based on broad monitoring activities and
represent evaluations generally used for political assessments.
The most common parameters to describe the indicator ”nitrate leaching” are:
a) the nitrate leaching rate; and
b) the potential for nitrate leaching.
N-management practices to attain environmental sustainability are expected to
have both low nitrate leaching potential and low nitrate leaching rate.
46
Nitrate leaching rate
The nitrate leaching rate can be described by the N-concentration in the
leaching water and the amount of leakage water. Table 4-7 shows research
results indicating nitrate leaching rates with respect to a per hectare and a per
output unit scale.
Table 4-7: Nitrate leaching rates from organic farming relative to conventional
farming systems (farm comparisons)
Reference scale Compared with conventional farming the nitrate
leaching rates in organic farming systems are
Author
lower similar higher
per hectare
> 50% Smilde (1989),
Vereijken (1990)
57% Paffrath (1993)
40% 1 5 2 Blume et al. (1993)
50% Reitmayr (1995)
per output
grain 5 1 5 2 Fink (1997)
milk 10% Lundström (1997)
1 sandy soil
2 loamy soil
The results from relevant farm comparisons presented above show that the
nitrate leaching rates in organic farming systems in most of the studies are
significantly lower compared to those of conventional farming systems. Only on
loamy soil did Blume et al. (1993) find nitrate leaching rates similar to
conventional farming. Hege et al. (1996) corroborated these results of
significantly lower nitrate concentrations in the leakage. In on-farm
investigations, they observed a 50% decrease in nitrate concentration in leakage
within 4 years after conversion (Hege et al. 1996).
It is interesting to note that if the nitrate leaching rate is related to the output of
grain and milk, organic systems tend to perform similar or even worse than
conventional systems.
Only modest losses due to leaching were observed during monitoring of a
horticultural unit of an organic farm with more than 500 kg N/ha in one single
application and often more than 300 kg N/ha and year through manure
applications considering the large amounts applied. However, the drained water
contained more than the admissible concentration of 11.3 mg/l in five out of the
six consecutive sampling dates (Watson et al. 1994).
47
Potential for nitrate leaching
The appropriate parameters to measure the potential for nitrate leaching during
the non-vegetative period are the Nmin-N content in soil in autumn and the N-
balance. As the latter will be the subject of Chapter 3.3.1, this section will
concentrate on the impact of organic farming on the Nmin-N content in the soil.
Results from relevant long-term trials seem somewhat contradictory in
connection with nitrate leaching potential. This is due to the fact that most trials
are conducted with Nt-equality of the compared systems or even equal organic
manure application rates. While no differences between organic and
conventional systems were observed in the Swiss DOC trial (Alföldi et al.
1992), another long-term trial (Darmstadt) showed varying tendencies:
Wessolek et al. (1989) and Meuser et al. (1990) observed higher nitrate leaching
potential whereas later investigations found lower potentials (Bachinger 1996).
Varying results were also obtained in comparative on-farm investigations.
While Pfaffrath (1993) found no differences in the Nmin-N/ha content in autumn
between organically and conventionally managed soils in the five year
investigations, Van Leeuwen and Wijnands (1997a and b) observed Nmin-N/ha
contents in autumn in organically managed soil at Nagele, Netherlands which
were 50% higher than the conventionally (integrated) managed one (in field
vegetable production with very high import of manure). Rinne et al. (1993)
mention that the post harvest release of soluble nitrogen into soil might be
higher in organic than in conventional farming. On the other hand Brandhuber
and Hege (1992) conducted a deep layer analysis and reported that the Nmin-
N/ha content in autumn on the organic farms was 60% lower than on the
conventional farms compared. Another investigation on three different sites
over a period of three years observed a range from 23 kg/ha lower to 15 kg/ha
higher soil Nmin-N/ha content in autumn on organic farms in comparison to
neighbouring conventional farms (Meyercordt 1997). Various other
investigations also contribute to the assumption that organic farming has a
lower nitrate leaching potential than conventional farming systems (Berg et al.
1997; Eltun and Fugleberg 1996; Hege et al. 1996).
Recently, extensive data has been published based on large scale surveys
obtained by official national or country-specific nitrate screening of water
protection areas in Germany and Denmark (Table 4-8). These screenings
represent a broader picture based on profound data bases. They often include
integrated farming systems focusing on reduced N-fertiliser application and
advisory standards in their assessment. The results presented in Table 4-8
indicate that organic farming results in a lower or at least similar potential for
nitrate leaching into ground and surface water. Furthermore, the absolute values
generally do not exceed the critical level. Nevertheless, it has to be kept in mind
that the difference in the nitrate
48
leaching potential between organic farming and integrated systems, or systems
using extensification measures, have become smaller in recent years due to
improved conventional management of mineral N-fertilisation (Piorr and
Werner 1998). This seems to apply especially to water reclamation areas with
high advisory standards and extensive control measures.
Table 4-8: Nitrate screening in water protection areas: Results of kg N
min
-
N/ha content* of organic fields relative to conventional fields
Crop Result Relative to conventional n Country
conventional = 100
Not specified lower 80 1220 DE1
lower 60 9 DE2
similar – 26 DK3
Cereals similar 614 DE1
Potatoes similar – 71 DE1
lower 75 7 DE4
Oil seeds lower 70 14 DE1
Maize lower 60 50 DE1
Fodder
legumes similar – 174 DE1
* soil (0-90 cm) in autumn, conventional and organic with 20% N-fertilisation reduction
1 Übelhör (1997)
2 Kurzer et al. (1997)
3 Kristensen et al. (1994)
4 Baumgärtel (1997)
Estimates on nitrate leaching, based on model calculations, indicated losses of
27 kg/ha per year at a stocking density which corresponds with Fertiliser Units
(FU) of 0.9 FU/ha and 32 kg/ha at a stocking density of 1.4 FU/ha (Askegaard
and Eriksen 1997). A model calculation, which compared the complete
conversion of the German state of Brandenburg to the current status, estimated a
potential for the reduction of nitrate leaching amounting to 17 - 26 kg N/ha.
These results are also valid under the assumption of an increasing proportion of
legumes in the rotation of up to 40% (Piorr, H.P. et al. 1997).
Although not all the results reviewed support the hypothesis that organic
farming results in less nitrate leaching than conventional farming, a strong
tendency towards a decreased risk of and absolute levels of nitrate leaching can
be deduced.
49
The nitrate load from organically cultivated soils tends to be lower than from
conventionally cultivated ones because:
the stocking rates and thus fertilisation levels are lower than in the
conventional mean and overall N-input in organic farming systems is lower
because their application is bound to organic manure and its incorporation
into the soil, and nutrient availability of stable manure is lower than of slurry
due to its mixture with straw (Dabbert and Piorr 1998);
applied stable manure results in a lower risk from run-off than slurry; and
extensive rotations of various crops, extensive soil covers during winter,
intercrops, underseeds, and fallows of several years are more common in
organic than in conventional farming (Leclerc 1995; Nocquet et al. 1996).
However, two critical areas for potential water pollution by organic farming
have been identified and extensively investigated:
a) the composting of stable manure; and
b) the management of residual nitrogen from legumes.
Extensive storage and composting of farmyard manure on non-paved surfaces
can result in leakage into and contamination of ground and surface water
(Berner et al. 1990; Dewes 1997; Dewes and Schmitt 1995; Heß et al. 1992). As
this depends on the dry matter content of the manure, leakage can be avoided by
covering the manure piles, adding mineral powder (e.g. bentonite) and including
a pre-rotting phase on paved ground (Dewes 1997; Dewes and Schmitt 1995).
Considerable nitrate leaching can also occur when the N-pool accumulated by
legumes is poorly managed, i.e. by grubbing clover grass in early autumn and
subsequently sowing crops with low N-demand. In this case, high
mineralisation of up to 80-100 kg Nmin-N/ha, and subsequent nitrate leaching
rates of up to 50 kg NO3-N /ha, may occur (Fiedler and Elers 1997; Heß 1989
and 1995; Heß et al. 1992; König 1995; NRA 1992; Piorr 1992 and 1995;
Reents 1991; Reents and Meyer 1995; Stein-Bachinger 1993).
Generally, the element most susceptible to nitrate leaching of organic crop
rotations are clover grass ley elements. Their nitrate leaching potential is 74 –
250 kg NO3 –N/ ha (NRA 1992). However, the frequency of tillage of clover
grass leys within a crop rotation is low (every 6-7 years). A non-comparative
on-farm investigation of total nitrate leaching from arable crops and grass
estimated a mean N-load of 10-21 kg/ha per year, depending on the farm and
crop rotation. This leads to the conclusion that appropriate nitrogen
management of individual crops can help considerably in reducing the nitrate
leaching potential of whole rotations
Gelöscht:
Gelöscht:
Gelöscht:
50
(EFRC 1992, Phillip and Stopes 1995). Especially in recent years, efficient
strategies of transferring leguminous born N into the nutrient cycle without
losses were developed and put into practise (Dabbert and Piorr 1998; Heß et al.
1992; Justus and Köpke 1990 and 1995).
To summarise: the reviewed material showed that the nitrate leaching rate of
organically managed soils is lower than that of conventionally managed ones.
As far as the potential for nitrate leaching in terms of soil Nmin-N/ha content in
autumn is concerned, the studies reviewed came to varying conclusions. While
long-term studies and comparative on-farm investigations show contrasting
results, nitrate screenings indicate that the soil Nmin-N/ha content in autumn is
lower on organic than on conventional farms. Thus, it can be concluded that
organic farming can contribute to water protection, especially with respect to
the risk and actual rates of nitrate leaching. The growing consciousness of
problematic phases, i.e. grubbing of clover ley, has resulted in improvements of
organic management practices with respect to water protection targets.
Especially in water protection areas sensitive to water contamination by nitrate,
several national standards and special advisory services provide
recommendations for organic farmers such as:
reducing livestock density;
using appropriate animal husbandry practices (NRA 1992);
limiting the use of liquid manure;
using compost with a high homogeneity and reduced spreading quantities;
and
increasing green manuring (Orgaterre 1997).
4.2.2.2 Pesticides
Toxic contamination of water by pesticides can result from leaching through the
soil profile into ground water, by surface runoff, by erosion of contaminated
soil particles, or directly by pesticide application close to surface waters. For a
comprehensive evaluation of the risk of pesticide residues to the environment,
the OECD (1997) recommends a risk as well as a state approach within the
framework of environmental indicators.
Currently in the EU, total annual sales of pesticides per hectare amount to 4.2
kg of active ingredients/ha (Brouwer 1997). Independent of the farming system,
it can be assumed that the best prevention of environmental risks associated
with synthetic pesticides is not using them at all. In this respect, organic farming
provides almost complete protection of natural resources as opposed to other
farming systems, because the use of synthetic pesticides is completely banned
(Heß et al. 1992; MAFF 1998a; NRA 1992). A trial comparing different
agricultural systems observed a significant reduction of applied active
ingredients per ha with an increased
51
introduction of non-synthetic measures of pest control in integrated farming
systems. Nevertheless, for most pesticides, the zero-risk that is realised in the
organic system could not be reached (Table 4-9).
Table 4-9: Reduction of pesticide input in different farming systems
Reduction of active matter/ha (%)
conventional1 organic2
Herbicides 46 – 80 100
Fungicides 26 – 93 100
Insecticides 25 – 89 100
Growth regulators 53 – 59 100
Nematicides 71 - 100 100
Source: Van Leeuwen and Wijnands (1997a, b), adapted
1 data for 1986-90
2 data for 1992-95, biodynamic
The risks associated with pesticides that are in use in organic farming have
hardly been investigated. Most pesticides allowed in organic farming are of
natural origin such as silicates or extracts of medicinal plants. As far as active
ingredients are concerned, only three are permitted: Rotenone, pyrethroids and
copper.
So far no water contamination by these active substances has been reported,
although this might simply be due to the fact that they might not yet have been
included in monitoring programs (Unwin et al. 1995). Most likely, however,
this is due to the fact that both pyrethroids and rotenone are highly non-mobile
in soil. Furthermore, pyrethroids are only slightly persistent and rotenone is
impersistent. Therefore, the risk of water contamination by these substances is
low, especially when other factors, such as the extremely low application rates,
are taken into account. Copper occurs naturally in soils and water and is
therefore difficult to monitor as contamination resulting from pesticide
application. It is not clear whether copper from pesticide use can be identified in
groundwater or have any significant impact on water quality and aquatic
environments, although the influence of copper-based pesticides on metabolic
processes can be deduced theoretically. In conclusion, it can be said that these
might enter water resources only through misuse or accidental spill (Unwin et
al. 1995).
Based on results published so far, a threat to water quality by the pesticides
permitted in organic farming can not be assumed. Together with the fact of the
complete absence of synthetic pesticides, however, a conclusive
52
assessment of organic farming with respect to the environmental indicator
"contamination of water by pesticides" has to be rated as highly superior as
compared to conventional farming.
4.2.2.3 Summary: Ground and surface water
Based on a review of published and grey literature on this issue, it can be
concluded that the ban of mineral N-fertilisers and synthetic pesticides on the
one hand, and the low level of nitrogen cycling within the farm because of low
livestock densities on the other, are important contributions which organic
farming makes to water protection.
In detail, the following conclusions can be drawn:
Organic farming results in lower or similar nitrate leaching rates than
integrated or conventional agriculture, as shown by low autumn Nmin-N
residues in the soil of almost all relevant crops. However, the differences are
becoming smaller with increasing implementation of water protection
measures in conventional farming (Dabbert and Piorr 1999).
Farm comparisons show that actual leaching rates per ha are up to 57%
lower on organic than on conventional fields. The leaching rates per
production unit (t of crop, kg of milk) were similar or slightly higher.
Farm yard manure composted uncovered and on unpaved surfaces can be a
focal point of nitrate leaching.
Critical situations concerning nitrate leaching may arise from ploughing
legumes at the wrong time or being followed by unfavourable crops.
However, consciousness of the problem and its handling has increased
recently and alternative measures have been developed and introduced in
organic farming practise.
Organic farming poses no risk of ground and surface water pollution by
synthetic pesticides. The active ingredients of permitted pesticides have not
been properly monitored nor their effects sufficiently investigated.
Even though incorrect organic farm management practices could indeed bear
some potential risks of polluting ground and surface water, the detrimental
environmental effects from organic farming tend to be generally lower than
those of conventional farming systems. Thus organic farming is the preferred
agricultural system for water reclamation areas.
A conclusive assessment of the effects of organic farming on ground and
surface water is given in the following table (Table 4-10):
53
Table 4-10: Assessment of organic farming's impact on the indicator
subcategory "Ground and surface water " compared with
conventional farming
+ + + o – –
5
Nitrate leaching
5
Pesticides
5
Ground and surface water total
Legend: Organic farming performs: ++ much better, + better, o the same, – worse, – –
much worse than conventional farming
5 Subjective confidence interval of the final assessment marked with 5
4.2.3 Climate and air
The climatic change (greenhouse effect) is globally recognised as one of the