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Soil Fertility and Biodiversity in Organic Farming Science


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An understanding of agroecosystems is key to determining effective farming systems. Here we report results from a 21-year study of agronomic and ecological performance of biodynamic, bioorganic, and conventional farming systems in Central Europe. We found crop yields to be 20% lower in the organic systems, although input of fertilizer and energy was reduced by 34 to 53% and pesticide input by 97%. Enhanced soil fertility and higher biodiversity found in organic plots may render these systems less dependent on external inputs.
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DOI: 10.1126/science.1071148
, 1694 (2002); 296Science
et al.Paul Maeder,
Soil Fertility and Biodiversity in Organic Farming (this information is current as of December 4, 2006 ):
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already weakened by overfishing (18). Possi-
ble mechanisms by which such changes may
be manifest are reviewed by Sundby (19).
Because changes in community structure re-
flect the adjustment of pelagic ecosystems to
modifications in water masses, currents, and/
or atmospheric forcing, it is clearly important
to continue to monitor plankton associations,
which provide us with a valuable means of
checking the well-being of marine ecosys-
tems in the North Atlantic Ocean and possi-
bly in other oceanic regions.
References and Notes
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Ecol. Prog. Ser. 204, 299 (2000).
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21. We are grateful to the staff of the Sir Alister Hardy
Foundation for Ocean Science and the shipping compa-
nies, captains, and crew whose sustained support has
allowed the long-term maintenance of the Continuous
Plankton Recorder (CPR) data set. The main support for
this work was from the United Kingdom, the Nether-
lands, the Atlantic Salmon Trust, the French PNEC Art 4
Programme, and the EU MAST-III programme. Consor-
tium support for the CPR survey is provided by agencies
from the following countries: Canada, the Faeroes,
France, Iceland, the Intergovernmental Oceanographic
Commission, Ireland, the Netherlands, Portugal, the
United Kingdom, and the United States.
Supporting Online Material
Materials and Methods
Figs. S1 to S4
27 February 2002; accepted 25 April 2002
Soil Fertility and Biodiversity in
Organic Farming
Paul Ma¨der,
* Andreas Fliebach,
David Dubois,
Lucie Gunst,
Padruot Fried,
Urs Niggli
An understanding of agroecosystems is key to determining effective farming
systems. Here we report results from a 21-year study of agronomic and eco-
logical performance of biodynamic, bioorganic, and conventional farming sys-
tems in Central Europe. We found crop yields to be 20% lower in the organic
systems, although input of fertilizer and energy was reduced by 34 to 53% and
pesticide input by 97%. Enhanced soil fertility and higher biodiversity found in
organic plots may render these systems less dependent on external inputs.
Intensive agriculture has increased crop
yields but also posed severe environmental
problems (1). Sustainable agriculture would
ideally produce good crop yields with mini-
mal impact on ecological factors such as soil
fertility (2, 3). A fertile soil provides essential
nutrients for crop plant growth, supports a
diverse and active biotic community, exhibits
a typical soil structure, and allows for an
undisturbed decomposition.
Organic farming systems are one alterna-
tive to conventional agriculture. In some Eu-
ropean countries up to 8% of the agricultural
area is managed organically according to Eu-
ropean Union Regulation (EEC) No. 2092/91
(4). But how sustainable is this production
method really? The limited number of long-
term trials show some benefits for the envi-
ronment (5, 6 ). Here, we present results from
Research Institute of Organic Agriculture, Acker-
strasse, CH-5070 Frick, Switzerland.
Swiss Federal
Research Station for Agroecology and Agriculture,
Reckenholzstrasse 191, CH-8046 Zu¨rich, Switzerland.
*To whom correspondence should be addressed. E-
Fig. 2. Principal component analysis of long-
term changes in SST in the North Atlantic
Ocean. (A) First eigenvector and principal com-
ponent (PC) (in black). Long-term changes in
NHT anomalies (in red) and the Pearson corre-
lation coefficient between the first PC and NHT
anomalies are indicated. (B) Second eigenvec-
tor and PC (in black). The long-term changes in
the winter NAO (in red) and the Pearson cor-
relation coefficient between the second PC and
the NAO index are indicated. The signal dis-
played by the first PC is highly correlated pos-
itively with NHT anomalies [Pearson correla-
tion coefficient (r
) 0.67, P 0.001]. In the
Subarctic Gyre, the values of the second PC
decreased until about 1993 and then increased.
The long-term change in the second PC is high-
ly correlated negatively with the NAO index
0.63, P 0.001). Probability was cor-
rected to account for temporal autocorrelation
with the method recommended by Pyper et al.
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the 21-year “DOK” system comparison trial
(bio-Dynamic, bio-Organic, and “Konventio-
nell”), which is based on a ley rotation. The
field experiment was set up in 1978 on a loess
soil at Therwil, Switzerland [(7) and support-
ing online material). Two organic farming
systems (biodynamic, BIODYN; bioorganic,
BIOORG) and two conventional systems (us-
ing mineral fertilizer plus farmyard manure:
CONFYM; using mineral fertilizer exclusive-
ly: CONMIN) are emulated in a replicated
field plot experiment (table S1 and fig. S1).
Both conventional systems were modified to
integrated farming in 1985. Crop rotation,
varieties, and tillage were identical in all
systems (table S2).
We found nutrient input (N, P, K) in the
organic systems to be 34 to 51% lower than
in the conventional systems, whereas mean
crop yield was only 20% lower over a period
of 21 years (Fig. 1, Table 1), indicating an
efficient production. In the organic systems,
the energy to produce a crop dry matter unit
was 20 to 56% lower than in conventional
and correspondingly 36 to 53% lower per unit
of land area (tables S4 and S5).
Potato yields in the organic systems were
58 to 66% of those in the conventional plots
(Fig. 1), mainly due to low potassium supply
and the incidence of Phytophtora infestans.
Winter wheat yields in the third crop rotation
period reached an average of 4.1 metric tons
per hectare in the organic systems. This cor-
responds to 90% of the grain harvest of the
conventional systems, which is similar to
yields of conventional farms in the region (8).
Differences in grass-clover yields were small.
Cereal crop yields under organic manage-
ment in Europe typically are 60 to 70% of
those under conventional management,
whereas grassland yields are in the range of
70 to 100%. Profits of organic farms in Eu-
rope are similar to those of comparable con-
ventional farms (9). Appropriate plant breed-
ing may further improve cereal yields in or-
ganic farming. There were minor differences
between the farming systems in food quality
The maintenance of soil fertility is im-
portant for sustainable land use. In our
experimental plots, organically managed
soils exhibit greater biological activity than
the conventionally managed soils. In con-
trast, soil chemical and physical parameters
show fewer differences (Fig. 2).
Soil aggregate stability as assessed by the
percolation method (11) and the wet sieving
method (12) was 10 to 60% higher in the
organic plots than in the conventional plots
(Fig. 2A). These differences reflect the situ-
ation as observed in the field (Fig. 3, A and
B), where organic plots had a greater soil
stability. We found a positive correlation be-
tween aggregate stability and microbial bio-
mass (r 0.68, P 0.05), and between
aggregate stability and earthworm biomass
(r 0.45, P 0.05).
Soil pH was slightly higher in the organic
systems (Fig. 2B). Soluble fractions of phos-
phorus and potassium were lower in the or-
ganic soils than in the conventional soils,
whereas calcium and magnesium were high-
er. However, the flux of phosphorus between
the matrix and the soil solution was highest in
the BIODYN system (13). Soil microorgan-
isms govern the numerous nutrient cycling
reactions in soils. Soil microbial biomass in-
creased in the order CONMIN CON-
soils of the organic systems, dehydrogenase,
protease, and phosphatase activities were
higher than in the conventional systems, in-
dicating a higher overall microbial activity
and a higher capacity to cleave protein and
organic phosphorus (12). Phosphorus flux
through the microbial biomass was faster in
organic soils, and more phosphorus was
bound in the microbial biomass (14, 15).
Evidently, nutrients in the organic systems
are less dissolved in the soil solution, and
microbial transformation processes may
contribute to the plants’ phosphorus supply.
Fig. 1. Yield of winter wheat,
potatoes, and grass-clover in the
farming systems of the DOK tri-
al. Values are means of six years
for winter wheat and grass-clo-
ver and three years for potatoes
per crop rotation period. Bars
represent least significant differ-
ences (P 0.05).
Table 1. Input of nutrients, pesticides, and fossil energy to the DOK trial systems.
Nutrient input is the average of 1978–1998 for BIODYN, BIOORG, and CONFYM
and 1985–1998 for CONMIN. Soluble nitrogen is the sum of NH
-N and NO
The input of active ingredients of pesticides was calculated for 1985–1991.
Energy for production of machinery and infrastructure, in fuel, and for the
production of mineral fertilizer and pesticides has been calculated for 1985–1991.
Total nitrogen
Soluble nitrogen
Pesticides (kg active
ingredients ha
(GJ ha
BIODYN 99 34 24 158 0 12.8
BIOORG 93 31 28 131 0.21 13.3
CONFYM 149 96 43 268 6 20.9
CONMIN 125 125 42 253 6 24.1
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Mycorrhizae as members of the soil com-
munity ameliorate plant mineral nutrition and
contribute to soil aggregate formation (16 ).
Root length colonized by mycorrhizae in or-
ganic farming systems was 40% higher than
in conventional systems (7) (Fig. 2C).
Biomass and abundance of earthworms
were higher by a factor of 1.3 to 3.2 in the
organic plots as compared with conventional
(17) (Fig. 2D). We also investigated epigaeic
arthropods that live above ground, because
they are important predators and considered
sensitive indicators of soil fertility. Average
activity density of carabids, staphylinids, and
spiders in the organic plots was almost twice
that of the conventional plots (18) (Fig. 2D).
Healthy ecosystems are characterized by
high species diversity. The DOK trial shows
that organic farming allows the development of
a relatively diverse weed flora. Nine to 11 weed
species were found in organically managed
wheat plots and one species in conventional
plots. Between 28 and 34 carabid species were
found in the BIODYN system, 26 to 29 species
in the BIOORG system, and 22 to 26 species in
the CONFYM system (18). Some specialized
and endangered species were present only in
the two organic systems. Apart from the pres-
ence and diversity of weeds, direct effects of
pesticides and the density of the wheat crop
stand are most likely influencing arthropod ac-
tivity and diversity.
One of the particularly remarkable find-
ings, presented in Fig. 4, was a strong and
significant increase in microbial diversity
(BIOLOG Inc., Hayward, CA) in the order
DYN, and an associated decrease in the met-
abolic quotient (qCO
)(19). According to
Odum’s theory on the strategy of ecosystem
development, the ratio of total respiration to
total biomass decreases during succession in
an ecosystem (20). This quotient has been
adapted to soil organisms (21), where CO
evolution is a biological process mainly gov-
erned by microorganisms. The lower qCO
the organic systems, especially in the BIO-
DYN system, indicates that these communi-
ties are able to use organic substances more
for growth than for maintenance.
Under controlled conditions, the diverse
microbial community of the BIODYN soil
decomposed more
C-labeled plant material
than the ones of the conventional soils (22).
In the field, light fraction particulate organic
matter, indicating undecomposed plant mate-
rial, decayed more completely in organic sys-
tems (23). Hence, microbial communities
Fig. 2. Physical, chemical, and biological soil
properties in soils of the DOK farming systems.
Analyses were done within the plough horizon
(0 to 20 cm) except for soil fauna. Results are
presented relative to CONFYM ( 100%) in
four radial graphs. Absolute values for 100% are
as follows. (A) Percolation stability, 43.3 ml
; aggregate stability, 55% stable aggre-
gates 250 m; bulk density, 1.23 g cm
O), 6.0; organic carbon, 15.8 g C
phosphorus, 21.4 mg P kg
; potassium, 97.5
; calcium, 1.7 g Ca kg
; magnesium,
125 mg Mg kg
.(C) Microbial biomass, 285 mg
; dehydrogenase activity, 133 mg TPF
; protease activity, 238 mg tyrosine
; alkaline phosphatase, 33 mg phenol
; saccharase, 526 mg reduced sugar
; mycorrhiza, 13.4% root length colo-
nized by mycorrhizal fungi. (D) Earthworm bio-
mass, 183 g m
; earthworm abundance, 247
individuals m
; carabids, 55 individuals;
staphylinids, 23 individuals; spiders, 33 individ-
uals. Arthropods have not been determined in
the CONMIN system because of the field trial
design. Significant effects were found for all
parameters except for bulk density, C
, and
potassium (analysis of variance; P 0.05). For
methods, see table S3.
Fig. 3. Biodynamic (A) and conventional (B) soil surface in winter wheat plots. Earthworm casts and
weed seedlings are more frequent in the biodynamic plot. Disaggregation of soil particles in the
conventional plots leads to a smoother soil surface. Wheat row distance is 0.167 m. Source: T.
Alfo¨ldi, Research Institute of Organic Agriculture [Forschungsinstitut fu¨r biologischen Landbau
31 MAY 2002 VOL 296 SCIENCE www.sciencemag.org1696
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with an increased diversity in organic soils
transform carbon from organic debris into
biomass at lower energy costs, building up a
higher microbial biomass. Accordingly, the
functional role of diverse plant communities
in soil nitrate utilization has been quoted
(24), as well as the significance of mycorrhi-
zal diversity for phosphorus uptake and plant
productivity (25). The consistent results of
these two studies (24, 25) and our own within
the soil-plant system support the hypothesis
that a more diverse community is more effi-
cient in resource utilization. The improve-
ment of biological activity and biodiversity
below and above ground in initial stages of
food webs in the DOK trial is likely to pro-
vide a positive contribution toward the devel-
opment of higher food web levels including
birds and larger animals.
The organic systems show efficient re-
source utilization and enhanced floral and
faunal diversity, features typical of mature
systems. There is a significant correlation
(r 0.52, P 0.05) between above-ground
(unit energy per unit crop yield) and below-
ground (CO
evolution per unit soil microbial
biomass) system efficiency in the DOK trial.
We conclude that organically manured, le-
gume-based crop rotations utilizing organic
fertilizers from the farm itself are a realistic
alternative to conventional farming systems.
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26. We sincerely thank all co-workers in the DOK trial,
especially W. Stauffer and R. Frei and the farmer
groups. We also thank T. Boller and A. Wiemken and
two unknown referees for their helpful comments.
This work was supported by the Swiss Federal
Office for Agriculture and the Swiss National Sci-
ence Foundation.
Supporting Online Material
Materials and Methods
Fig. S1
Tables S1 to S5
21 February 2002; accepted 26 April 2002
Control of Stomatal
Distribution on the Arabidopsis
Leaf Surface
Jeanette A. Nadeau and Fred D. Sack*
Stomata regulate gas exchange and are distributed across the leaf epidermis
with characteristic spacing. Arabidopsis stomata are produced by asymmetric
cell divisions. Mutations in the gene TOO MANY MOUTHS (TMM) disrupt
patterning by randomizing the plane of formative asymmetric divisions and by
permitting ectopic divisions. TMM encodes a leucine-rich repeat–containing
receptor-like protein expressed in proliferative postprotodermal cells. TMM
appears to function in a position-dependent signaling pathway that controls the
plane of patterning divisions as well as the balance between stem cell renewal
and differentiation in stomatal and epidermal development.
Stomata allow gas exchange and thus are key
to the survival of land plants, yet the genes
controlling stomatal development are poorly
understood (1, 2). Both the number and dis-
tribution of stomata are regulated during leaf
development. Stomata are formed after a se-
ries of asymmetric divisions of transiently
self-renewing precursors termed meriste-
moids [fig. S1 (3)]. Stomata are continually
produced during the mosaic development of
the leaf, and many form by division of cells
next to preexisting stomata (Fig. 1A). Correct
spacing results when the plane of formative
asymmetric divisions is oriented so that the
new precursor, the satellite meristemoid, does
not contact the preexisting stoma or precursor
(1, 4 ). Intercellular signaling provides spatial
cues that regulate division orientation and
may also block asymmetric division in cells
adjacent to two stomata or precursors (4 ).
The recessive too many mouths (tmm) muta-
tion randomizes the plane of asymmetric di-
vision in cells next to a single stoma or
precursor and permits asymmetric divisions
in cells next to two stomata or precursors,
thus producing clusters of stomata (Fig. 1, A
and C). Also, tmm meristemoids divide fewer
times before assuming the determinate guard
mother cell fate. These phenotypes suggest
that TMM is required for cells to respond
appropriately to their position during stoma-
tal development and that TMM participates in
intercellular signaling.
With the use of positional cloning (3),
TMM was found to encode a leucine-rich
repeat (LRR)–containing receptor-like pro-
tein of 496 amino acids with a molecular
weight of 54 kD (Fig. 2A). The predicted
protein product contains 10 uninterrupted
plant-type LRRs (5) and a putative COOH-
terminal transmembrane domain. TMM en-
Department of Plant Biology, Ohio State University,
1735 Neil Avenue, Columbus, OH 43210, USA.
*To whom correspondence should be addressed. E-
Fig. 4. Soil microbial functional diversity
(Shannon index H’) and metabolic quotient
soil basal respiration/soil microbial
biomass) correlate inversely. A higher diversity
in the organic plots is related to a lower qCO
indicating greater energy efficiency of the more
diverse microbial community. The Shannon in-
dex is significantly different between both con-
ventional systems (CONFYM, CONMIN) and
the BIODYN system, the qCO
, between
CONMIN and BIODYN (P 0.05).
R EPORTS SCIENCE VOL 296 31 MAY 2002 1697
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... Therefore, organic farms are more dependent on the conservation of soil fertility including soil P mobility, for example, through crop rotation (Watson et al., 2002) or organic fertilization (Ahmad et al., 2014;Fließbach et al., 2007), which also can lead to higher concentrations of soil organic carbon (Gattinger et al., 2012). However, long-term organic cultivation does not seem to have any influence on P org forms in soil compared with conventional fertilization (Keller et al., 2012), which may be explained by higher mineralization rates through soil microorganisms (Mäder et al., 2002). Nevertheless, the differences in cultivation and fertilization have raised the question of whether common P extraction methods that were developed for conventional agriculture are also applicable to organic agriculture with a high internal return of P org . ...
... Soil microbial activity may be increased under organic farming conditions (Mäder et al., 2002) which can especially be attributed to organic fertilization (Hartmann et al., 2015). Further, an increased soil microbial activity can be beneficial for plants if moderately available P can be transformed into more mobile P forms (Shen et al., 2016). ...
Full-text available
Background Organic farmers frequently report sufficient yield levels despite low or even very low soil phosphorous (P) contents questioning the applicability of widely used laboratory methods for soil P testing for organic farming. Aims The aim of this study was to compare the validity of a broad range of different soil extraction methods on soils under organic management from South West Germany and to test the correlation of the measured soil P concentration with plant offtake. Methods Twenty‐two soil samples of eight different organic farms were extracted with different solutions: (1) water, (2) CAL, (3) Olsen, (4) Mehlich 3, (5) Bray P1, (6) Bray P2, (7) NaOH+Na 2 EDTA, and (8) total P. The results were then correlated with above ground plant P. Results Spearman's rank correlation coefficient ( r s ) of correlations between above ground plant P and extractable soil P (Water‐P, CAL‐P, and Olsen‐P [+active charcoal {+AC}]) determined with ICP‐OES were strong (0.94, 0.90, and 0.93, respectively). Among the tested methods, above ground plant P showed a strong correlation with CAL‐P as detected by ICP‐OES ( r s = 0.90) and colorimetry ( r s = 0.91). The comparison of CAL‐P data provided by farmers and CAL‐P analyzed during this research showed discrepancies between the results. Conclusions The results of this study indicate that the CAL method can be used in organic farming despite a low extraction of organic P (P org ). Furthermore, it is recommended for farmers to take soil samples for analyses regularly and interpret changes in P in the long‐term instead of interpreting individual samples.
... recommendation in land management, vis-à-vis soil conservation and food supply, influences the environment quality by maintaining crop yield with minimal decline in soil fertility and providing nutrient elements to plants and also in the soil microorganisms diversity and their activities (Mäder et al., 2002). However, it should be noted that soil health depends on the type of management systems and intensity of actions that reduce soil degradation and its resultant ecosystem contaminations. ...
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Maintaining soil quality is a priority, especially in areas with environmental stresses such as drought. Therefore, application of amendments such as biochar for improving soil quality in these conditions received increased attention. On the one hand, soil quality is a versatile integrated indicator of soil changes in response to different applied treatments (e.g., biochar and drought) and managerial practices. Conversely, the integrated impacts of biochar and drought on plant performance and soil quality indices (SQIs) have been not studied in previous works. Therefore, we aimed to (1) evaluate the integrated impacts of cattle manure-derived biochar (0, 25, 50, and 100 t ha⁻¹) and soil moisture levels (100, 70, and 55% of field capacity, FC) on soybean yield and soil–plant nutrients status; (2) determine quality indices of the Integrated and Nemero SQI in the postharvest soils based on two indicator selection scenarios of the Total (TDS) and Minimum (MDS) Data Set by applying Principal Component Analysis (PCA) to decline soil parameters to the most effective ones in response to the applied levels of biochar and soil moisture conditions; (3) determine the most effective soil attributes to calculate SQIs; and (4) determine the soil quality (SQ) grades under the applied treatments. Selection criterion was also calculated to select the effective properties of principal component which in turn substantially controls changes. According to the results of PCA, from the 26 applied physicochemical properties, seven principal components (PCs) had eigenvalues of greater than one and showed 86.95% of data cumulative variance. Among the 26 studied soil indicators, the most effective ones with the highest importance to soil quality indices which determined as the minimum data set were soluble potassium, mean weight diameter of aggregates obtained by wet sieving and also that of dry sieving, penetration resistance, pH of saturated paste, geometric mean diameter of aggregates measured by dry sieving, and available zinc with the eigenvectors of 0.964, 0.911, 0.968, 0.894, 0.874, 1.009, and 0.702, respectively. The highest positive correlations between soil quality indices and plant nutrients concentration were obtained in soils received 25 t biochar ha⁻¹. The highest Integrated SQI based on the TDS was observed with addition of 100 t biochar ha⁻¹ under 70% and 55% field capacity conditions. Integrated SQI based on the TDS approach increased from grade IV to grade I when high rates of biochar were applied in drought stress conditions. This indicates that biochar has a remarkable capability for increasing the capacity of the soils to retain water as well as for improving SQ which is very important, particularly in semi-arid and arid regions facing water scarcity problems.
... Flooding irrigation water appeared to possess a core microbiome that consisted of common environmental bacteria isolated from irrigation and soil. However, it is in close proximity to soil, which harbours a complex and dynamic bacterial community (Mäder et al. 2002). Ralstonia and Escherichia-Shigella are amongst the highest contributing core members in overhead irrigation water. ...
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Morogo is an African indigenous term used for leafy green vegetables harvested in the wild or cultivated in small-scale farms and consumed by the local populations of the region. Small-scale farmers have gained recognition as important suppliers of morogo to informal settlements. In commercial production systems, leafy green vegetables have increasingly been reported as associated with foodborne pathogens and disease outbreaks. Little is known of the presence of these organisms on leafy green vegetables in the informal unregulated food systems. This study aimed to profile bacterial communities in irrigation water (flooding and overhead irrigation water) and leafy green vegetables ( Brassica rapa L. chinensis and Brassica rapa varieties of morogo ) to establish the natural bacterial flora at the water-fresh produce interface from five small-scale farms in two provinces in South Africa. Illumina MiSeq high-throughput sequencing showed that each farm exhibited a unique bacterial community composition, with an overall high relative abundance of Proteobacteria, Firmicutes and Actinobacteria, including prominent families such as Burkholderiaceae (48%), Enterobacteriaceae (34%), Bacillales Family XII (8%), Rhodobacteraceae (3%), Micrococcaceae (1.98%) and Pseudomonadaceae (1.79%). Specific Enterobacteriaceae Serratia , Enterobacter , Salmonella , Shigella , Escherichia coli , Buchnera, Citrobacter , Klebsiella and Proteus were identified, in addition to unique communities associated with plant or irrigation water source. These findings suggest that the edible plant microbiome can play an important role as transient contributor to the human gut and has the potential to affect overall health.
... Among the cultivated crops, rice is one of the most demanding staple food crops, and its demand is increasing daily due to the rise in the global population [1,2]. Moreover, there is increasing awareness of using organic food and organic fertilisers due to health consciousness, which can reduce synthetic nitrogen (N) and phosphorous (P) requirements parameters (substrate, inoculum and NPK) via a principal component analysis to reduce the dimensionality of the variable factors. ...
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The present study evaluates the synergistic application of an anaerobic digestate for enhanced rice yield. The study utilised the digestate as a fertilizer with various inoculum-to-substrate (IS) ratios of anaerobic digestion from cow dung and water hyacinth (CW–BF) with combinations of NPK (16-22-22) fertiliser for rice yield optimisation. The outcome of the combined digestate and fertilizer application on rice cultivation was observed in terms of parameters such as the number of tillers, panicle number, panicle length, fertile panicles, and 1000-grain weight. The digestate combination of CW–BF:NPK (3:1:1) resulted in the highest grain yield (7521 kg/hectare) with increased panicle length, test weight, and more filled grains than the other combinations. Moreover, various machine-learning approaches were used to study the efficacy of the different combinations of applied fertilizer (cow dung, water hyacinth, and NPK). The gradient-boosting machine-learning model was appropriate for predicting the modelling based on the measured data. Principal component analysis revealed NPK as the first principal component with high loading values and the digestate as the second principal component, which indicates its crucial role in fertiliser preparation. Therefore, deploying such hybridized fertilisers using the proper statistical analysis and machine-learning approaches can improve rice yield, which would be essential for the socio-economic uplifting of marginal rice farmers.
... 2009). Thus, soils play a major role in maintaining a balanced global carbon cycle (Ecological Society of America, 2000) and this should be explored in mitigating climate change (Lal, 2004;Mäder et al., 2002). ...
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Keywords: Compost has the potential to trap carbon in the soil while supplying nutrients needed for the crop use beyond one cropping season. This study therefore investigated the residual fertility and carbon sequestration potential of accelerated compost on an Alfisol and Ultisol in Southwest Nigeria, using maize as the test crop. The experiment was laid out in Randomized Complete Block Design (RCBD) with three replicates. The treatments applied during the main planting where residual effect was explored (at the second planting) were accelerated compost (AC) at the rate of 60, 90, 120, 150 and 180 kgN/ha. The mineral fertilizer (NPK 15-15-15) and conventional compost (CC), both at 60 kgN/ha and control (no soil additive) were the checks. Data were collected on the maize grain yields and post cropping soil chemical properties. Data were analysed using ANOVA at á. On an Alfisol, both the 60 kgN/ha AC (2.31 t/ha) and 0.05 60 kgN/ha CC (2.41 t/ha) performed significantly higher than the 60 kgN/ha NPK (2.21 t/ha) and similar trend was observed on an Ultisol. The AC sequestered more carbon (58 % extra relative to the control) than the CC (9 %) at the same 60 kgN/ha rate on an Alfisol. Also on an Ultisol, accelerated compost sequestered more carbon (14 % extra relative to the control) than the CC (8 %) at the same 60 kgN/ha rate. It could therefore be concluded that the shortness in maturity of the accelerated compost used for this study does not limit its residual fertility and carbon sequestration potential. Accelerated compost, Carbon sequestration, Organic wastes, Soil types. Les potentiels résiduels et de séquestration du carbone du compost accéléré dans deux types de sols Résumé Le compost a le potentiel de piéger le carbone dans le sol tout en fournissant les éléments nutritifs nécessaires à l'utilisation des cultures au-delà d'une saison de culture. Cette étude a donc étudié la fertilité résiduelle et le potentiel de séquestration du carbone du compost accéléré sur un Alfisol et un Ultisol dans le sud-ouest du Nigeria, en utilisant le maïs comme culture test. L'expérience a été présentée dans la conception de blocs complets randomisés (RCBD) avec trois répétitions. Les traitements appliqués lors de la plantation principale où l'effet résiduel a été exploré (à la deuxième plantation) étaient du compost accéléré (CA) à raison de 60, 90, 120, 150 et 180 kgN/ha. L'engrais minéral (NPK 15-15-15) et le compost conventionnel (CC), tous deux à 60 kgN/ha et le témoin (sans additif du sol) ont été les témoins. Des données ont été recueillies sur les rendements en AFRICAN JOURNAL OF ORGANIC AGRICULTURE AND ECOLOGY grains de maïs et les propriétés chimiques du sol après la culture. Les données ont été analysées par ANOVA à á0,05. Sur un Alfisol, les 60 kgN/ha AC (2,31 t/ha) et 60 kgN/ha CC (2,41 t/ha) ont donné des résultats significativement plus élevés que les 60 kgN/ha NPK (2,21 t/ha) et une tendance similaire a été observée sur un Ultisol. Le climatiseur (AC) a séquestré plus de carbone (58 % en plus par rapport au témoin) que le CC (9 %) au même taux de 60 kgN/ha sur un Alfisol. Toujours sur Ultisol, le compost accéléré a séquestré plus de carbone (14 % de plus par rapport au témoin) que le CC (8 %) au même taux de 60 kgN/ha. On pourrait donc conclure que la brièveté de la maturité du compost accéléré utilisé pour cette étude ne limite pas sa fertilité résiduelle et son potentiel de séquestration du carbone.
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In a long-term comparison of agricultural systems, bio-dynamic, organic and conventional farming have been compared since 1978. The treatments differ mainly in plant protection management and fertilization (organic vs. mineral, and intensity). The experimental field is situated on a Luvisol from loess in Therwil (Switzerland). Here, the fauna of beneficial epigaeic arthropods (carabids, staphylinids and spiders) in differently cultivated winter wheat plots was investigated with pitfall traps (live catches) in 1988, 1990 and 1991. Compared with the conventional plots (= 100%), the bio-dynamic plots contained 193% of epigaeic arthropods, the organic plots 188%. The activity- density of carabids, staphylinids and spiders was higher in the bio-dynamic and the organic than in the conventional plots in all three years. In two out of three years, the difference between the conventional and the biodynamic, organic plots was significant. For carabids, the differences between treatments were most pronounced in spring. In the biological plots, the species number of carabids was higher in each year than in the conventional ones: On average bio-dynamic plots contained 18–24 species, organic plots 19–22 species and the conventional ones 13–16 species. The frequency distribution of the carabid species was also more even in the bio-dynamic and the organic plots. The influences of plant protection and fertilization on epigaeic arthropod populations are discussed.
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In a long-term trial, the earthworm populations of two biological farming systems, two conventional systems and one control treatment were compared in a seven year crop rotation on a Luvisol from loess. The earthworms were investigated by handsorting at four dates during 1990–92. Nicodrilus longus (Ude), N. nocturnus (Evans), N. caliginosus (Savigny) and Allolobophora rosea (Savigny) were the dominant earthworm species in all treatments. The earthworm biomass and density, the presence of anecic species, and the number of juveniles were significantly higher in the biological than in the conventional or unfertilized plots. In addition, more earthworm species were found in the biological plots. In this trial, plant protection management seems to be the main factor responsible for the differences in earthworm populations.
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In agricultural systems, optimization of carbon and nitrogen cycling through soil organic matter can improve soil fertility and yields while reducing negative environmental impact. A basic tenet that has guided the management of soil organic matter for decades has been that equilibrium levels of carbon and nitrogen are controlled by their net input and that qualitative differences in these inputs are relatively unimportant. This contrasts with natural ecosystems in which there are significant effects of species composition and litter quality on carbon and nitrogen cycling,. Here we report the net balances of carbon and nitrogen from a 15-year study in which three distinct maize/soybean agroecosystems are compared. Quantitative differences in net primary productivity and nitrogen balance across agroecosystems do not account for the observed changes in soil carbon and nitrogen. We suggest that the use of low carbon-to-nitrogen organic residues to maintain soil fertility, combined with greater temporal diversity in cropping sequences, significantly increases the retention of soil carbon and nitrogen, which has important implications for regional and global carbon and nitrogen budgets, sustained production, and environmental quality.
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THE functioning and sustainability of ecosystems may depend on their biological diversity1-8. Elton's9 hypothesis that more diverse ecosystems are more stable has received much attention1,3,6,7,10-14, but Darwin's proposal6,15 that more diverse plant communities are more productive, and the related conjectures4,5,16,17 that they have lower nutrient losses and more sustainable soils, are less well studied4-6,8,17,18. Here we use a well-replicated field experiment, in which species diversity was directly controlled, to show that ecosystem productivity in 147 grassland plots increased significantly with plant biodiversity. Moreover, the main limiting nutrient, soil mineral nitrogen, was utilized more completely when there was a greater diversity of species, leading to lower leaching loss of nitrogen from these ecosystems. Similarly, in nearby native grassland, plant productivity and soil nitrogen utilization increased with increasing plant species richness. This supports the diversity-productivity and diversity-sustainability hypotheses. Our results demonstrate that the loss of species threatens ecosystem functioning and sustainability.
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 Arbuscular mycorrhizal (AM) root colonization was studied in a long-term field trial in which four farming systems currently in use in Switzerland were continuously applied to a randomized set of plots at a single field site from 1978 till 1993. There were two low-input farming systems (organic and bio-dynamic) and two high-input (conventional) farming systems (according to Swiss guidelines of integrated plant production with and without farmyard manure). The systems had an identical 7-year crop rotation and tillage scheme and differed essentially only in the amount and type of fertilizer supplied and in plant protection management. The percentage of root colonization by AM fungi was determined in field samples 2–3 times over the growing season in crops in the rotation, namely in winter wheat (Triticum aestivum L. cv. Sardona), vetch-rye and grass-clover. We found the percentage of root length colonized by AM fungi to be 30–60% higher (P≤0.05) in the plants grown in soils from the low-input farming systems than in those grown in conventionally farmed soils. Approximately 50% of the variation of AM root colonization was explained by chemical properties of the soils (pH, soluble P and K, exchangeable Mg), the effect of soluble soil P being most pronounced. The potential of the field soils from the differently managed plots to cause symbiosis with AM fungi was tested in a glasshouse experiment, using wheat as a host plant. Soils from the low-input farming systems had a greatly enhanced capacity to initiate AM symbiosis. The relative differences in this capacity remained similar when propagules of the AM fungus Glomus mosseae were experimentally added to the soils, although overall root colonization by AM fungi was 2.8 times higher.
We studied microbiological processes in organic P transformations in soils cultivated with conventional and biological farming systems during the 13th and 14th year of different cropping systems. The treatments included control, biodynamic, bioorganic, and conventional plots and a mineral fertilization treatment. Different P fractions were investigated using a sequential fractionation method. Labile organic P, extracted by 0.5 M NaHCO3, was not affected by the farming systems. However, residual organic P remaining in the soil at the end of the sequential fractionation procedure showed that the biodynamic treatment, in particular, led to a modification of the composition of organic P. Labile organic P, organic P extractable in 0.1 M NaOH, and total residual P all showed temporal fluctuations. As total residual P consists of more than 70% organic P, it can be assumed that residual organic P contributed to these variations. This result indicates that chemically resistant organic P participates in short-term accumulation and mineralization processes. All biological soil parameters tested in this study showed significant temporal fluctuations, mainly attributed to differences in climatic conditions between years, but possibly also related to the growth cycle of the crop. The higher values of the biological soil parameters in the biodynamic and bioorganic treatments were explained by the greater importance of manure and the different plant protection strategies. The level of phosphatase activity and mineralization of organic C indicated a higher turnover of organic substrates, and thus of organic P, in the biodynamic and bioorganic treatments. Biological parameters were shown to be critical for assessing the significance of organic P in the soil P turnover.
The effects of conventional and biological farming systems on soil P dynamics were studied by measuring some microbiological parameters after 13 years of different cropping systems. The treatments included control, biodynamic, bio-organic, and conventional plots and a mineral fertilizer treatment. The farming systems differed mainly in the form and quantity of nutrients applied and in the plant protection strategies. The results of a sequential fractionation procedure showed that irrespective of the form of P applied, neither 0.5 M NaHCO inf3 sup- nor 0.1 M NaOH-extractable organic P, but only the inorganic fractions, were affected. The residual organic P, not extracted by NaHCO3 or NaOH was increased in the biodynamic and bio-organic plots. The soil microbial biomass (ATP content) and the activity of acid phosphatase were also higher in both biologically managed systems. These results were attributed to the higher quantity of organic C and organic P applied in these systems, but also to the absence of or severe reduction in chemical plant protection. The relationship between acid soil phosphatase and residual organic P was interpreted as an indication that this fraction might be involved in short-term transformations. The measurement of the intensity, quantity, and capacity factors of available soil P using the 32P isotopic exchange kinetic method showed that P could not be the factor limiting crop yield in the biological farming systems. The kinetic parameters describing the ability of P ions to leave the soil solid phase, deduced from isotopic exchange, were significantly higher for the biodynamic treatment than for all other treatments. This result, showing a modification of chemical bonds between P ions and the soil matrix, was explained by the higher Ca and organic matter contents in this system.