ArticlePDF Available

Organic Agriculture and the Global Food Supply

Authors:

Abstract

The principal objections to the proposition that organic agriculture can contribute significantly to the global food supply are low yields and insufficient quantities of organically acceptable fertilizers. We evaluated the universality of both claims. For the first claim, we compared yields of organic versus conventional or low-intensive food production for a global dataset of 293 examples and estimated the average yield ratio (organic:non-organic) of different food categories for the developed and the developing world. For most food categories, the average yield ratio was slightly <1.0 for studies in the developed world and >1.0 for studies in the developing world. With the average yield ratios, we modeled the global food supply that could be grown organically on the current agricultural land base. Model estimates indicate that organic methods could produce enough food on a global per capita basis to sustain the current human population, and potentially an even larger population, without increasing the agricultural land base. We also evaluated the amount of nitrogen potentially available from fixation by leguminous cover crops used as fertilizer. Data from temperate and tropical agroecosystems suggest that leguminous cover crops could fix enough nitrogen to replace the amount of synthetic fertilizer currently in use. These results indicate that organic agriculture has the potential to contribute quite substantially to the global food supply, while reducing the detrimental environmental impacts of conventional agriculture. Evaluation and review of this paper have raised important issues about crop rotations under organic versus conventional agriculture and the reliability of grey-literature sources. An ongoing dialogue on these subjects can be found in the Forum editorial of this issue.
Organic agriculture and the global
food supply
Catherine Badgley
1
, Jeremy Moghtader
2,3
, Eileen Quintero
2
, Emily Zakem
4
, M. Jahi Chappell
5
,
Katia Avile
´
s-Va
´
zquez
2
, Andrea Samulon
2
and Ivette Perfecto
2,
*
1
Museum of Palaeontology, University of Michigan, Ann Arbor, MI 48109, USA.
2
School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI 48109 USA.
3
Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA.
4
School of Art and Design, University of Michigan, Ann Arbor, MI 48109, USA.
5
Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA.
*Corresponding author: perfecto@umich.edu
Accepted 9 June 2006 Research Paper
Abstract
The principal objections to the proposition that organic agriculture can contribute significantly to the global food supply are
low yields and insufficient quantities of organically acceptable fertilizers. We evaluated the universality of both claims. For
the first claim, we compared yields of organic versus conventional or low-intensive food production for a global dataset of
293 examples and estimated the average yield ratio (organic : non-organic) of different food categories for the developed
and the developing world. For most food categories, the average yield ratio was slightly <1.0 for studies in the developed
world and >1.0 for studies in the developing world. With the average yield ratios, we modeled the global food supply that
could be grown organically on the current agricultural land base. Model estimates indicate that organic methods could
produce enough food on a global per capita basis to sustain the current human population, and potentially an even larger
population, without increasing the agricultural land base. We also evaluated the amount of nitrogen potentially available
from fixation by leguminous cover crops used as fertilizer. Data from temperate and tropical agroecosystems suggest that
leguminous cover crops could fix enough nitrogen to replace the amount of synthetic fertilizer currently in use. These results
indicate that organic agriculture has the potential to contribute quite substantially to the global food supply, while reducing
the detrimental environmental impacts of conventional agriculture. Evaluation and review of this paper have raised
important issues about crop rotations under organic versus conventional agriculture and the reliability of grey-literature
sources. An ongoing dialogue on these subjects can be found in the Forum editorial of this issue.
Key words: organic agriculture, conventional agriculture, organic yields, global food supply, cover crop
Introduction
Ever since Malthus, the sufficiency of the global food
supply to feed the human population has been challenged.
One side of the current debate claims that green-revolution
methods—involving high-yielding plant and animal vari-
eties, mechanized tillage, synthetic fertilizers and biocides,
and now transgenic crops—are essential in order to produce
adequate food for the growing human population
1–4
. Green-
revolution agriculture has been a stunning technological
achievement. Even with the doubling of the human pop-
ulation in the past 40 years, more than enough food has been
produced to meet the caloric requirements for all of the
world’s people, if food were distributed more equitably
5
.
Yet Malthusian doubts remain about the future. Indeed,
given the projection of 9 to 10 billion people by 2050
6
and the global trends of increased meat consumption and
decreasing grain harvests per capita
4
, advocates argue that
a more intensified version of green-revolution agriculture
represents our only hope of feeding the world. Another side
of the debate notes that these methods of food production
have incurred substantial direct and indirect costs and may
represent a Faustian bargain. The environmental price of
green-revolution agriculture includes increased soil erosion,
surface and groundwater contamination, release of green-
house gases, increased pest resistance, and loss of biodiver-
sity
7–14
. Advocates on this side argue that more sustainable
methods of food production are essential over the long
term
15–17
.
If the latter view is correct, then we seem to be pursuing
a short-term solution that jeopardizes long-term environ-
mental sustainability. A central issue is the assertion that
Renewable Agriculture and Food Systems: 22(2); 86–108 doi:10.1017/S1742170507001640
#
2007 Cambridge University Press
alternative forms of agriculture, such as organic methods,
are incapable of producing as much food as intensive
conventional methods do
1,3,5
. A corollary is that organic
agriculture requires more land to produce food than con-
ventional agriculture does, thus offsetting any environ-
mental benefits of organic production
18
. Additionally,
critics have argued that there is insufficient organically
acceptable fertilizer to produce enough organic food
without substantially increasing the land area devoted to
agriculture
3
.
Here, we evaluate the potential contribution of organic
agriculture to the global food supply. Specifically, we
investigate the principal objections against organic agri-
culture making a significant contribution—low yields and
insufficient quantities of organic nitrogen fertilizers. The
term ‘organic’ here refers to farming practices that may be
called agroecological, sustainable, or ecological; utilize
natural (non-synthetic) nutrient-cycling processes; exclude
or rarely use synthetic pesticides; and sustain or regenerate
soil quality. These practices may include cover crops,
manures, compost, crop rotation, intercropping, and bio-
logical pest control. We are not referring to any particular
certification criteria and include non-certified organic
examples in our data.
Methods
We compiled data from the published literature about the
current global food supply, comparative yields between
organic and non-organic production methods, and biolog-
ical nitrogen fixation by leguminous crops. These data were
the basis for estimating the global food supply that could be
grown by organic methods and the amount of nitrogen that
could become available through increased use of cover
crops as green manures.
Esti mation of the gl obal food supply
Estimation of the global food supply grown by organic
methods involved compiling data about current global food
production, deriving ratios of the yields obtained from
organic versus non-organic production methods, and apply-
ing these yield ratios to current global production values.
Global food production. Summary data from the Food
and Agricultural Organization (FAO) for 2001
19
docu-
ment the current global food supply—grown primarily by
conventional methods in most of the developed world and
primarily by low-intensive methods in most of the devel-
oping world. The FAO provides estimates of the current
food supply in 20 general food categories
19
which we
modified for our study. We combined three pairs of cate-
gories (into sugars and sweeteners, vegetable oils and oil-
crops, meat and offals). We omitted from consideration
three categories (spices, stimulants, and ‘miscellaneous’),
because they contribute few calories and little nutritional
value to the daily diet and lack comparative data for
organic versus non-organic production. In addition, we
reported data for seafood and ‘other aquatic products’ but
did not estimate yield ratios for these categories, since
most of these foods are currently harvested from the wild.
Alcoholic beverages were reported since they contribute
significantly to the average daily caloric intake, but no
assessment of organic yields was made. The data pres-
ented for yield ratios pertain to ten categories covering
the major plant and animal components of human diets.
Food-production data of the FAO include both commer-
cial and domestic production and exclude losses during
harvest. Pre-harvest crop losses are not included in the
estimates; these losses may be substantial
20
but are not
necessarily more serious for organic production, since a
host of methods is available for managing pests
21,22
. For
each country or region, the FAO data for the food supply
available for human consumption take into account food
production, exports, imports, and stocks, as well as losses
of production to become livestock feed, seed, or waste
19
.
‘Waste’ refers to post-harvest loss during storage, transport,
and processing. We compiled this information for the
world, for developed countries, and for developing
countries, following the FAO classification of countries as
developed or developing.
Deriving yield ratios. We estimated the global organic
food supply by multiplying the amount of food in the
current (2001) food supply by a ratio comparing average
organic : non-organic yields. Comparisons of organic to
non-organic production are available for many plant foods
and a few animal foods. For each of 293 comparisons of
organic or semi-organic production to locally prevalent
methods under field conditions, the yield ratio is the ratio
of organic : non-organic production. A ratio of 0.96, for
example, signifies that the organic yield is 96% that of
the conventional yield for the same crop. The compari-
sons include 160 cases with conventional methods and
133 cases with low-intensive methods. Most examples are
from the peer-reviewed, published literature; a minority
come from conference proceedings, technical reports, or
the Web site of an agricultural research station. Like
Stanhill’s 1990 survey of organic and conventional pro-
duction
23
, our data include numerous comparisons from
paired farms and controlled experiments at research
stations. The studies range in observation length from a
single growing season to over 20 years. Despite the ob-
servation that yields following conversion from conven-
tional to organic production initially decline and then
may increase with time
24,25
(but see ref. 23), we included
studies regardless of duration. All of Stanhill’s examples
(which are included here) were from the developed world,
whereas our dataset also includes diverse examples from
the developing world. No attempt was made to bias the
results in favor of organic yields; many examples from
developed and developing countries exhibit low compara-
tive yields. We avoided generalizations based on country-
wide or regional average yields by organic or conventional
methods. Some examples are based on yields before and
after conversion to organic methods on the same farm.
Organic agriculture and the global food supply 87
We grouped examples into ten general food categories
and determined the average yield ratio for all cases in
each food category. For the complete dataset and sources,
see Appendix 1. Table 1 presents the average yield ratios of
these food categories for all studies combined (the world),
studies in developed countries, and studies in developing
countries. If no data were available (e.g., tree nuts) for
estimating global organic production, then we used the
average yield ratio for all plant foods, or all animal foods
where relevant. For individual studies in which several
yield ratios were reported for a single crop (e.g., 0.80–2.00)
grown under the same treatment, we took the average as
the value for the study. When different treatments were
described, we listed a value for each treatment. Averaging
the yield ratios across each general food category re-
duced the effects of unusually high or low yield ratios
from individual studies. As these studies come from many
regions in developed and developing countries, the average
yield ratios are based on a broad range of soils and climates.
The average yield ratio is not intended as a predictor of
the yield difference for a specific crop or region but as
a general indicator of the potential yield performance of
organic relative to other methods of production.
Studies in the global south usually demonstrate increases
in yields following conversion to organic methods
(Table 1C), but these studies are not comparable with
those in the developed world. At present, agriculture in
developing countries is generally less intensive than in the
developed world. Organic production is often compared
with local, resource-poor methods of subsistence farming,
which may exhibit low yields because of limited access by
farmers to natural resources, purchased inputs, or extension
services. While adoption of green-revolution methods has
typically increased yields, so has intensification by organic
methods
26
. Such methods more often result in non-certified
than in certified organic production, since most food
produced is for local consumption where certification is
not at issue
27
. Data from these studies are relevant for our
inquiry, which seeks quantitative comparisons between
organic production and prior methods, whether by conven-
tional or subsistence practices, since both prevailing
methods contribute to global food production.
Estimating the global food supply. Using the average
yield ratio for each food category, we estimated the
amount of food that could be grown organically by multi-
plying the amount of food currently produced times the
average yield ratio (Tables 2 and 3). Following the FAO
methodology
19
, this estimate was then proportionally
reduced for imports, exports, and losses (e.g., Table 2,
column D) to give the estimated organic food supply
after losses (e.g., Table 2, column G), which is the food
supply available for human consumption. We assumed
that all food currently produced is grown by non-organic
methods, as the global area of certified organic agriculture
is only 0.3%
28
.
We constructed two models of global food pro-
duction grown by organic methods. Model 1 applied the
organic : non-organic (conventional) yield ratios derived
from studies in developed countries to the entire agri-
cultural land base (Table 2). This model effectively
assumes that, if converted to organic production, the low-
intensity agriculture present in much of the developing
world would have the same or a slight reduction in yields
that has been reported for the developed world, where
green-revolution methods now dominate. Model 2 applied
the yield ratios derived from studies in the developed world
to food production in the developed world, and the yield
ratios derived from studies in the developing world to food
production in the developing world (Table 3). The sum of
these separate estimates provides the global estimate.
Table 1. Average yield ratio (organic : non-organic) and standard error (S.E.) for ten individual food categories recognized by the FAO
19
and three summary categories. Average yield ratio based on data from 91 studies (see Appendix 1 for data and sources). (A) All countries.
(B) Developed countries. (C) Developing countries.
Food category
(A) World (B) Developed countries (C) Developing countries
N Av. S.E. N Av. S.E. N Av. S.E.
Grain products 171 1.312 0.06 69 0.928 0.02 102 1.573 0.09
Starchy roots 25 1.686 0.27 14 0.891 0.04 11 2.697 0.46
Sugars and sweeteners 2 1.005 0.02 2 1.005 0.02
Legumes (pulses) 9 1.522 0.55 7 0.816 0.07 2 3.995 1.68
Oil crops and veg. oils 15 1.078 0.07 13 0.991 0.05 2 1.645 0.00
Vegetables 37 1.064 0.10 31 0.876 0.03 6 2.038 0.44
Fruits, excl. wine 7 2.080 0.43 2 0.955 0.04 5 2.530 0.46
All plant foods 266 1.325 0.05 138 0.914 0.02 128 1.736 0.09
Meat and offal 8 0.988 0.03 8 0.988 0.03
Milk, excl. butter 18 1.434 0.24 13 0.949 0.04 5 2.694 0.57
Eggs 1 1.060 1 1.060
All animal foods 27 1.288 0.16 22 0.968 0.02 5 2.694 0.57
All plant and
animal foods
293 1.321 0.05 160 0.922 0.01 133 1.802 0.09
88 C. Badgley et al.
In Model 1, the standard error of the estimate was
calculated for an affine transformation (i.e., rescaled to
world food production)
29
. In Model 2, the estimated global
organic food production was the sum of two regional
calculations—the yield ratios from the developed world
times the current food production in the developed world
and the yield ratios from the developing world times the
current food production in the developing world. The
standard error of the global estimate was determined for
the sum of two independent random variables
29
.
For Model 2, we did not adjust for the amount of
imported food in each food category. These amounts
ranged from 4.9 to 75.8% (imported as a proportion of total
food supply before losses) for the developed-world food
supply and from 0.7 to 22.7% for the developing-world
food supply
19
. Adjusting for imports in Model 2 would
elevate slightly to greatly the estimates of the organic food
supply in developed countries (Table 3, column F, because
a proportion of the actual food supply would be multiplied
by the higher average yield ratios for developing countries)
and would diminish slightly the estimates of the organic
food supply in the developing world (Table 3, column K,
because a proportion of the actual food supply would
be multiplied by the lower average yield ratios for the
developed world). The overall results would be qualita-
tively similar.
Additional model assumptions. Both models were
based on the pattern of food production and the amount
of land devoted to crops and pasture in 2001. The models
estimate the kinds and relative amounts of food that are
currently produced and consumed, including the same
pattern of total and per-capita consumption of meat,
sugars, and alcoholic beverages. Additional assumptions
include (1) the same proportion of foods grown for ani-
mal feed (e.g., 36% of global grain production), (2) the
same proportion of food wasted (e.g., 10% of starchy
roots), and (3) the same nutritional value of food (e.g.,
for protein and fat content in each food category), even
though changes in some of these practices would benefit
human or environmental health. Finally, we made no
assumptions about food distribution and availability, even
though changes in accessibility are necessary to achieve
global food security. These assumptions establish the
boundary conditions for the models but are not intended
as an assessment of the sustainability of the current global
food system.
Calor ies per capita
The calories per capita resulting from Models 1 and 2
were estimated by multiplying the average yield ratios
(organic : non-organic) in each food category by the FAO
estimate of per-capita calories currently available in that
food category
19
.
Ni tr og e n av ailabi lity with co v e r cr o ps
The main limiting macronutrient for agricultural production
is biologically available nitrogen (N) in most areas, with
Table 2. Actual (2001) food supply and estimates for Model 1. Data for world food supply from FAO Statistical Database
19
.
(A) Food category (B) Actual
world food
production
(C) Actual
food supply
after losses
(D) Supply as
proportion
of production
(C/B)
(E) Average
yield ratio
(Table 1)
(F) Estimated
organic food
production
(BrE)
(G) Estimated
organic food
supply after
losses (DrF)
Units 1000 Mg 1000 Mg 1000 Mg 1000 Mg
Grain products 1,906,393 944,611 0.50 0.928 1,769,133 876,599
Starchy roots 685,331 391,656 0.57 0.891 610,630 348,965
Sugars and sweeteners 1,666,418 187,040 0.11 1.005 1,674,917 187,975
Legumes (pulses) 52,751 32,400 0.61 0.816 43,044 26,438
Tree nuts 7,874 7,736 0.98 0.914
1
7,213 7,070
Oil crops and vegetable oils 477,333 110,983 0.23 0.991 472,559 109,984
Vegetables 775,502 680,802 0.88 0.876 679,340 596,383
Fruits, excl. wine 470,095 372,291 0.79 0.955 448,940 355,538
Alcoholic beverages 230,547 199,843 0.87
Meat and offal 252,620 247,446 0.98 0.988 249,588 244,476
Animal fats 32,128 19,776 0.62 0.968
2
31,100 19,143
Milk, excl. butter 589,523 479,345 0.81 0.949 559,457 454,898
Eggs 56,965 50,340 0.88 1.060 60,383 53,360
Seafood 124,342 95,699 0.77
Other aquatic products 10,579 8,514 0.80
Average for all foods 0.922
1
Average yield ratio for all plant foods (developed countries) was used, since no comparative yield data were available for this food
category.
2
Average yield ratio for all animal foods (developed countries) was used, since no comparative data were available for this food
category.
Mg = megagram = metric ton.
Organic agriculture and the global food supply 89
Table 3. Actual (2001) food supply and estimates for Model 2. Data for world food supply from FAO Statistical Database
19
; data for yield ratios from Table 1.
(A)
Food
category
(B)
Actual food
production
(C)
Actual food
supply after
losses
(D)
Food
supply as
proportion of
production
(E)
Av. yield
ratio
(F)
Est. organic
food supply
after losses
(G)
Actual food
production
(H)
Actual food
supply after
losses
(I)
Food
supply as
proportion of
production
(J)
Av. yield
ratio
(K)
Est. organic
food supply
after losses
(L)
World, est.
organic
food supply
after losses
(F + K)
----------------------------------Developed countries------------------------------ ----------------------------------Developing countries---------------------------- World
Units 1000 Mg 1000 Mg Ratio 1000 Mg 1000 Mg 1000 Mg Ratio 1000 Mg 1000 Mg
Grain
products
879,515 178,973 0.20 0.928 166,087 1,026,878 765,638 0.75 1.573 1,204,348 1,370,435
Starchy roots 176,120 96,754 0.55 0.891 86,207 509,211 294,902 0.58 2.697 795,352 881,559
Sugars and
sweeteners
332,987 56,274 0.17 1.005 56,555 1,333,430 130,766 0.10 1.736
4
227,010 283,565
Legumes
(pulses)
15,122 1,679 0.11 0.816 1,370 37,628 30,721 0.82 3.995 122,729 124,099
Tree nuts 2,194 3,336 1.52
1
0.914
2
3,049 5,680 4,400 0.77 1.736
4
7,638 10,687
Oil crops and
veg. oils
175,591 25,316 0.14 0.991 25,089 301,741 85,667 0.28 1.645 140,921 166,010
Vegetables 163,815 150,127 0.92 0.876 131,511 611,687 530,675 0.87 2.038 1,081,516 1,213,027
Fruits, excl.
wine
123,276 108,224 0.88 0.955 103,354 346,818 264,067 0.76 2.530 668,088 771,443
Alcoholic
beverages
122,376 110,827 0.91 108,172 89,016 0.82
Meat and
offal
111,595 106,865 0.96 0.988 105,583 141,024 140,581 1.00 1.802
5
253,327 358,909
Animal fats 21,420 10,881 0.51 0.968
3
10,533 10,708 8,895 0.83 1.802
5
16,029 26,561
Milk, excl.
butter
347,782 260,699 0.75 0.949 247,404 241,742 218,645 0.90 2.694 589,030 836,434
Eggs 18,645 16,697 0.90 1.060
3
17,699 38,320 33,643 0.88 1.802
5
60,625 78,323
Seafood 30,894 30,401 0.99 93,447 65,298 0.70
Other
aquatic
products
958 234 0.24 9,621 8,280 0.86
1
Ratio is greater than 1.0 because of imports. All values in column (C) include imports but these are typically a small proportion of food production; for tree nuts, however, about one-third
of the supply for the developed world is imported from the developing world.
2
Average yield ratio for all plant foods (developed countries) was used, since no comparative yield data were available for this food category.
3
Average yield ratio for all animal foods (developed countries) was used, since no comparative yield data were available for this food category.
4
Average yield ratio for all plant foods (developing countries) was used, since no comparative yield data were available for this food category.
5
Average yield ratio (developing countries) for all plant and animal foods was used, since no comparative yield data were available for this food category; the average for all foods was a
more conservative estimate than the average for animal foods alone.
90 C. Badgley et al.
phosphorus limiting in certain tropical regions
30
. For
phosphorus and potassium, the raw materials for fertility
in organic and conventional systems come largely from
mineral sources
31
and are not analyzed here.
Nitrogen amendments in organic farming derive from
crop residues, animal manures, compost, and biologically
fixed N from leguminous plants
32
. A common practice in
temperate regions is to grow a leguminous cover crop
during the winter fallow period, between food crops, or as a
relay crop during the growing season. Such crops are called
green manures when they are not harvested but plowed
back into the soil for the benefit of the subsequent crop. In
tropical regions, leguminous cover crops can be grown
between plantings of other crops and may fix substantial
amounts of N in just 46–60 days
33
. To estimate the amount
of N that is potentially available for organic production, we
considered only what could be derived from leguminous
green manures grown between normal cropping periods.
Nitrogen already derived from animal manure, compost,
grain legume crops, or other methods was excluded from
the calculations, as we assumed no change in their use.
The global estimate of N availability was determined from
the rates of N availability or N-fertilizer equivalency
reported in 77 studies—33 for temperate regions and 44 for
tropical regions, including three studies from arid regions
and 18 studies of paddy rice. N availability values in
kg ha
-1
were obtained from studies as either ‘fertilizer-
replacement value,’ determined as the amount of N
fertilizer needed to achieve equivalent yields to those
obtained using N from cover crops, or calculated as 66% of
N fixed by a cover crop becoming available for plant uptake
during the growing season following the cover crop
34
. The
full dataset and sources are listed in Appendix 2. We
estimated the total amount of N available for plant uptake
by multiplying the area currently in crop production (but
not already in leguminous forage production—large-scale
plantings of perennial legume systems) by the average
amount (kg ha
- 1
) of N available to the subsequent crop
from leguminous crops during winter fallow or between
crops (Table 4, Appendix 2).
Results and Discussion
Estimates of food and caloric production
under organic agriculture
Figure 1 compares the estimates from Models 1 and 2 to the
current food supply. According to Model 1, the estimated
organic food supply is similar in magnitude to the current
food supply for most food categories (grains, sweeteners,
tree nuts, oil crops and vegetable oils, fruits, meat, animal
fats, milk, and eggs). This similarity occurs because
the average yield ratios for these categories range from
0.93 to 1.06 (Figure 1, Tables 1B and 2). For other food
categories (starchy roots, legumes, and vegetables), the
average yield ratios range from 0.82 to 0.89, resulting in
somewhat lower production levels. The average yield ratio
for all 160 examples from developed countries is 0.92,
close to Stanhill’s average relative yield of 0.91
23
.
According to Model 2, the estimated organic food supply
exceeds the current food supply in all food categories, with
most estimates over 50% greater than the amount of food
currently produced (Figure 1). The higher estimates in
Model 2 result from the high average yield ratios of organic
versus current methods of production in the developing
world (Tables 1C and 3). The average yield ratio for
the 133 examples from the developing world is 1.80. We
consider Model 2 more realistic because it uses average
yield ratios specific to each region of the world.
These two models likely bracket the best estimate of
global organic food production. Model 1 may underesti-
mate the potential yield ratios of organic to conventional
production, since many agricultural soils in developed
countries have been degraded by years of tillage, synthetic
fertilizers, and pesticide residues. Conversion to organic
methods on such soils typically results in an initial decrease
Table 4. Estimated nitrogen available for plant uptake from biological nitrogen fixation with leguminous cover crops, for the world and
the US. For A, and F, data are from FAO Statistical Data Base
19
and USDA National Agriculture Statistics
35
; for B, data for the world are
from Gallaway et al., 1995
36
, and for the US from USDA-ERS
37
and the USDA National Agriculture Statistics
35
; for D, data are from
sources listed in Appendix 2. Estimates are based on land area not currently in leguminous forage production.
World US
A Area of total cropland 1513.2 million ha 177.3 million ha
B Area in leguminous forage production 170.0 million ha 36.0 million ha
C Area remaining for use in cover crops (A–B) 1362.1 million ha 141.3 million ha
D Average N availability or fertilizer-equivalence from winter
and off-season cover crops
102.8 kg N ha
- 1
yr
- 1
(n = 77, S.D. = 71.8)
95.1 kg N ha
- 1
yr
- 1
(n = 32, S.D. = 37.5)
E Estimated N available from additional cover crops without
displacing production (CrD)
140.0 million Mg N 13.4 million Mg N
F Total synthetic N fertilizer in current use by conventional
agriculture
82.0 million Mg N 10.9 million Mg N
G Estimated N fixed by cover crops in excess of current
synthetic fertilizer use (E–F)
58.0 million Mg N 2.5 million Mg N
Organic agriculture and the global food supply 91
in yields, relative to conventional methods, followed by an
increase in yields as soil quality is restored
7,25
. Model 2
may overestimate the yield ratios for the developing world
to the extent that green-revolution methods are practiced.
Both models suggest that organic methods could sustain
the current human population, in terms of daily caloric
intake (Table 5). The current world food supply after
losses
19
provides 2786 kcal person
-1
day
-1
. The average
caloric requirement for a healthy adult
38
is between 2200
and 2500 kcal day
-1
. Model 1 yielded 2641 kcal
person
- 1
day
- 1
, which is above the recommended value,
even if slightly less than the current availability of calories.
Model 2 yielded 4381 kcal person
- 1
day
- 1
, which is 57%
greater than current availability. This estimate suggests
that organic production has the potential to support a sub-
stantially larger human population than currently exists.
Significantly, both models have high yields of grains, which
constitute the major caloric component of the human diet.
Under Model 1, the grain yield is 93% that of current
production. Under Model 2, the grain yield is 145% that of
current production (Table 5).
The most unexpected aspect of this study is the con-
sistently high yield ratios from the developing world
(Table A1, Appendix 1). These high yields are obtained
when farmers incorporate intensive agroecological tech-
niques, such as crop rotation, cover cropping, agroforestry,
addition of organic fertilizers, or more efficient water
management
16,39
. In some instances, organic-intensive
methods resulted in higher yields than conventional
methods for the same crop in the same setting (e.g., the
system of rice intensification (SRI) in ten developing
countries
39
). Critics have argued that some of these
examples exceed the intrinsic yield limits set by crop
genetics and the environmental context
40
. (Such contro-
versy surrounds the ‘SRI’ and our data include studies from
both sides of this controversy.) Yet alternative agricultural
methods may elicit a different pathway of gene expression
than conventional methods do
41
. Thus, yield limits for
conventionally grown crops may not predict the yield limits
under alternative methods.
Crop rotation and yield-time adjustment
Organic grain production frequently uses a different
rotation system than conventional production. For example,
it is common in organic systems to have a three or four-
year rotation (with legumes or other crops) for corn, while
the conventional rotation often involves planting corn every
other year. In situations like this, it is difficult to make
yield comparisons between organic and conventional
systems without some sort of time adjustment. Although
the high variation among rotation systems worldwide
makes it impossible to provide a general time–yield ad-
justment, evaluating potential differences in performance
is important. A thorough evaluation of the rotation effect
requires knowledge of the plot-to-plot yield differences
between organic and conventional production and the rate
of decline of both organic and conventional production as
a function of the rotation sequence—information that has
not yet been experimentally demonstrated. While rotations
would undoubtedly differ under a global organic production
system, we have no basis for concluding that this system
would be unable to provide enough grain to feed the world.
Organ ic n itrogen ferti lizer
In 2001, the global use of synthetic N fertilizers was 82
million Mg (metric ton)
19
. Our global estimate of N fixed
by the use of additional leguminous crops as fertilizer is
140 million Mg, which is 58 million Mg greater than the
amount of synthetic N currently in use (Table 4). Even in
the US, where substantial amounts of synthetic N are used
in agriculture, the estimate shows a surplus of available
N through the additional use of leguminous cover crops
between normal cropping periods. The global estimate
is based on an average N availability or N-fertilizer
equivalency of 102.8 kg N ha
- 1
(S.D. 71.8, n = 76, Table
A2, Appendix 2). For temperate regions, the average is
95.1 kg N ha
- 1
(S.D. 36.9, n = 33) and for tropical regions,
the average is 108.6 kg N ha
- 1
(S.D. 99.2, n = 43). These
rates of biological N fixation and release can match N
availability with crop uptake and achieve yields equivalent
to those of high-yielding conventionally grown crops
42
.
In temperate regions, winter cover crops grow well in fall
after harvest and in early spring before planting of the
main food crop
43
. Research at the Rodale Institute
(Pennsylvania, USA) showed that red clover and hairy
vetch as winter covers in an oat/wheat–corn–soybean
rotation with no additional fertilizer inputs achieved yields
comparable to those in conventional controls
24,25,44
. Even
1400000
1200000
1000000
800000
600000
400000
200000
0
Grains
Starchy roots
Sugar & sweeteners
Legumes
Tree nuts
FAO FOOD CATEGORY
Actual
Model 1
Model 2
Oil crops
Vegetables
Fruits
Meat & offals
Animal fats
Milk
Eggs
Figure 1. Estimates of the global food supply from two models
of organic production compared with the actual food supply in
2001. Standard errors are given for food categories with multiple
studies of yield ratios (see Table 1 and Appendix 1).
92 C. Badgley et al.
in arid and semi-arid tropical regions, where water is
limiting between periods of crop production, drought-
resistant green manures, such as pigeon peas or groundnuts,
can be used to fix N
26,45,46
. Use of cover crops in arid
regions has been shown to increase soil moisture reten-
tion
47
, and management of dry season fallows commonly
practiced in dry African savannas can be improved with the
use of N-fixing cover crops for both N-fixation and weed
control
48
. Areas in sub-Saharan Africa which currently use
only very small amounts of N fertilizer (9 kg ha
-1
, much of
it on non-food crops
48
) could easily fix more N with the use
of green manures, leading to an increase in N availability
and yields in these areas
26
. In some agricultural systems,
leguminous cover crops not only contribute to soil fertility
but also delay leaf senescence and reduce the vulnerability
of plants to disease
30
.
Our estimates of N availability from leguminous
cover crops do not include other practices for increasing
biologically fixed N, such as intercropping
49
, alley crop-
ping with leguminous trees
50
, rotation of livestock with
annual crops
32
, and inoculation of soil with free-living
N-fixers
51
—practices that may add considerable N fertility
to plant and animal production
52
. In addition, rotation of
food-crop legumes, such as pulses, soy, or groundnuts, with
grains can contribute as much as 75 kg N ha
- 1
to the grains
that follow the legumes
33
.
These methods can increase the N-use efficiency by
plants. Since biologically available N is readily leached
from soil or volatilized if not taken up quickly by plants,
N use in agricultural systems can be as low as 50%
53
.
Organic N sources occur in more stable forms in carbon-
based compounds, which build soil organic matter and
increase the amount of N held in the soil
25,54
. Conse-
quently, the amount of N that must be added each year
to maintain yields may actually decrease, because the
release of organic N fixed in one season occurs over several
years
30
.
These results imply that, in principle, no additional
land area is required to obtain enough biologically available
N to replace the current use of synthetic N fertilizers.
Although this scenario of biological N fixation is simple, it
provides an assessment, based on available data, for one
method of organic N-fertility production that is widely used
by organic farmers and is fairly easy to implement on a
Table 5. Caloric values for the actual food supply (2001, data from FAO
19
) and for the organic food supply estimated in Models 1 and 2
(Tables 2 and 3). For alcoholic beverages, seafood, and other aquatic products, no change in caloric intake was assumed.
Food
category
Actual
food supply
after losses
Actual
per capita
supply
Model 1
results
Ratio of
model/
actual
Est. per
capita
supply,
Model 1
Model 2
results
Ratio of
model/
actual
Est. per
capita
supply,
Model 2
Units 1000 Mg Kcal day
- 1
1000 Mg Kcal day
- 1
1000 Mg Kcal day
- 1
Grain
products
944,611 1335.3 876,599 0.93 1239.1 1,370,435 1.45 1937.2
Starchy roots 391,656 146.8 348,965 0.89 130.8 881,559 2.25 330.4
Sugars and
sweeteners
187,040 247.7 187,975 1.01 249.0 283,565 1.52 375.6
Legumes
(pulses)
32,400 53.8 26,438 0.82 43.9 124,099 3.83 205.9
Tree nuts 7,736 8.9 7,070 0.91 8.2 10,687 1.38 12.3
Oil crops and
veg. oils
110,983 326.4 109,984 0.99 323.1 166,010 1.50 488.2
Vegetables 680,802 72.7 596,383 0.88 63.7 1,213,027 1.78 129.6
Fruits, excl.
wine
372,291 77.8 355,538 0.96 74.3 771,443 2.07 161.2
Alcoholic
beverages
199,843 64.0 64.0 64.0
Meat and
offals
247,446 211.1 244,476 0.99 208.6 358,909 1.45 306.2
Animal fats 19,776 61.2 19,143 0.97 59.2 26,561 1.34 82.2
Milk, excl.
butter
479,345 119.7 454,898 0.95 113.6 836,434 1.74 208.9
Eggs 50,340 32.3 53,360 1.06 34.2 78,323 1.56 50.2
Seafood 95,699 27.4 27.4 27.4
Other
aquatic
prod.
8,514 1.4 1.4 1.4
Total 2786.4 2640.7 4380.6
Organic agriculture and the global food supply 93
large scale. This scenario is not intended to be prescriptive
for any particular rotation or location, but to demonstrate
the possibility of this type of cover-cropping system to fix
large quantities of N without displacing food crops or
expanding land area. The Farm Systems Trial at the Rodale
Institute uses legume cover crops grown between main
crops every third year as the only source of N fertility and
reports comparable grain yields to those of conventionally
managed systems, while using non-legume winter cover
crops in other years to maintain soil quality and fertility and
to suppress weeds (R. Seidel and P. Hepperly, personal
communication, 2006). In practice, a range of methods
acceptable in organic agriculture provides critical flexibility
in N-management
32
, including many sources other than
cover crops. Although some environmental and economic
circumstances pose challenges to reliance on leguminous
fertilizers
55
, the full potential of leguminous cover crops
in agriculture is yet to be utilized. Implementation of
existing knowledge could increase the use of green manures
in many regions of the world
56
. Future selection for crop
varieties and green manures that have higher rates of N
fixation, especially in arid or semi-arid regions, and
perform well under N-limiting conditions, as well as for
improved strains of N-fixing symbionts, combined with
reductions in the amount of N lost from legume-based
production systems, and increases in the planting of
legumes, hold great promise for increasing the role of
biological N-fixation in fertility management
57
. The
capacity for increased reliance on legume fertilizers would
be even greater with substantive changes in the food
system, such as reduction of food waste and feeding less
grain to livestock
56
.
Prospects for More Sustainable
Food Production
Our results suggest that organic methods of food production
can contribute substantially to feeding the current and
future human population on the current agricultural land
base, while maintaining soil fertility. In fact, the models
suggest the possibility that the agricultural land base could
eventually be reduced if organic production methods
were employed, although additional intensification via
conventional methods in the tropics would have the same
effect. Our calculations probably underestimate actual
output on many organic farms. Yield ratios were reported
for individual crops, but many organic farmers use
polycultures and multiple cropping systems, from which
the total production per unit area is often substantially
higher than for single crops
48,58
. Also, there is scope for
increased production on organic farms, since most agri-
cultural research of the past 50 years has focused on
conventional methods. Arguably, comparable efforts
focused on organic practices would lead to further im-
provements in yields as well as in soil fertility and pest
management. Production per unit area is greater on small
farms than on large farms in both developed and developing
countries
59
; thus, an increase in the number of small
farms would also enhance food production. Finally, organic
production on average requires more hand labor than does
conventional production, but the labor is often spread out
more evenly over the growing season
25,60–62
. This require-
ment has the potential to alleviate rural unemployment
in many areas and to reduce the trend of shantytown
construction surrounding many large cities of the develop-
ing world.
The Millennium Ecosystem Assessment
17
recommends
the promotion of agricultural methods that increase food
production without harmful tradeoffs from excessive use
of water, nutrients, or pesticides. Our models demonstrate
that organic agriculture can contribute substantially to a
more sustainable system of food production. They suggest
not only that organic agriculture, properly intensified,
could produce much of the world’s food, but also that
developing countries could increase their food security with
organic agriculture. The results are not, however, intended
as forecasts of instantaneous local or global production
after conversion to organic methods. Neither do we claim
that yields by organic methods are routinely higher
than yields from green-revolution methods. Rather, the
results show the potential for serious alternatives to green-
revolution agriculture as the dominant mode of food
production.
In spite of our optimistic prognosis for organic
agriculture, we recognize that the transition to and practice
of organic agriculture contain numerous challenges—
agronomically, economically, and educationally. The
practice of organic agriculture on a large scale requires
support from research institutions dedicated to agro-
ecological methods of fertility and pest management, a
strong extension system, and a committed public. But it
is time to put to rest the debate about whether or not
organic agriculture can make a substantial contribution
to the food supply. It can, both locally and globally. The
debate should shift to how to allocate more resources for
research on agroecological methods of food production and
how to enhance the incentives for farmers and consumers
to engage in a more sustainable production system. Finally,
production methods are but one component of a sustainable
food system. The economic viability of farming methods,
land tenure for farmers, accessibility of markets, avail-
ability of water, trends in food consumption, and alleviation
of poverty are essential to the assessment and promotion of
a sustainable food system.
Acknowledgements. The course, ‘Food, Land, and Society’, at
the University of Michigan, provided the incentive for this
study. We are grateful to the farmers whose practices inspired
this research. We thank P. Hepperly and R. Seidel for discussion
and for providing us with data from the Rodale Farming
Systems Trial. Members of the New World Agriculture and
Ecology Group (NWAEG) provided useful insights. We
thank D. Boucher, L. Drinkwater, W. Lockeretz, D. Pimentel,
B. Needelman, J. Pretty, B. Schultz, G. Smith, P. Rosset, N.
Uphoff, and J. Vandermeer for comments on several versions of
94 C. Badgley et al.
this paper. This paper also benefited from the comments and
recommendations of anonymous reviewers.
References
1 Borlaug, N.E. 2000. Ending world hunger: the promise of
biotechnology and the threat of antiscience zealotry. Plant
Physiology 124:487–490.
2 Huang, J., Pray, C., and Rozelle, S. 2002. Enhancing the crops
to feed the poor. Nature 418:678–684.
3 Trewavas, A. 2002. Malthus foiled again and again. Nature
418:668–670.
4 Food and Agriculture Organization of the United Nations.
2004. The state of food and agriculture, 2003–2004.
Agriculture Series No. 35. Food and Agriculture Organization
of the United Nations, Rome.
5 Smil, V. 2000. Feeding the World—A Challenge for the 21st
Century. MIT Press, Cambridge, MA.
6 Population Division of the Department of Economic and
Social Affairs of the United Nations Secretariat. 2004. World
population prospects: the 2004 revision and world urbaniza-
tion prospects: the 2003 revision. Available at Web site: http://
esa.un.org/unpp (2 May 2005).
7 National Research Council. 1989. Alternative Agriculture.
National Academy Press, Washington, DC.
8 Pimentel, D., Harvey, C., Resosudarmo, P., Sinclair, K., Kurz,
D., McNair, M., Crist, S., Shpritz, L., Fitton, L., Saffouri, R.,
and Blair, R. 1995. Environmental and economic cost of soil
erosion and conservation benefits. Science 267:1117–1123.
9 Pimentel, D. 1996. Green revolution agriculture and
chemical hazards. The Science of the Total Environment
188 (Suppl. 1):S86–S98.
10 Matson, P.A., Parton, W.J., Power, A.G., and Swift, M.J.
1997. Agricultural intensification and ecosystem properties.
Science 277:504–509.
11 Tilman, D. 1999. Global environmental impacts of agricultural
expansion: the need for sustainable and efficient practices.
Proceedings of the National Academy of Sciences, USA 96:
5995–6000.
12 Heller, M.C. and Keoleian, G.A. 2003. Assessing the
sustainability of the US food system: a life cycle perspective.
Agricultural Systems 76:1007–1041.
13 Beman, J.M., Arrigo, K.R., and Matson, P.A. 2004. Agricul-
tural runoff fuels large phytoplankton blooms in vulnerable
areas of the ocean. Nature 434:211–214.
14 Relyea, R.A. 2005. The impact of insecticides and herbicides
on the biodiversity and productivity of aquatic communities.
Ecological Applications 15:618–627.
15 Tilman, D., Cassman, K.G., Matson, P.A., Naylor R., and
Polasky, S. 2002. Agricultural sustainability and intensive
production practices. Nature 418:671–677.
16 Pretty, J.N., Morison, J.I.L., and Hine, R.E. 2003. Reducing
food poverty by increasing agricultural sustainability in
developing countries. Agriculture, Ecosystems and Environ-
ment 95:217–234.
17 Millennium Ecosystem Assessment. 2005. Ecosystems and
Human Well-Being: Synthesis. Island Press, Washington, DC.
18 Green, R.E., Cornell, S.J., Scharlemann, J.P.W., and Balm-
ford, A. 2004. Farming and the fate of wild nature. Science
307:550–555.
19 Food and Agriculture Organization of the United Nations.
2003. FAO Statistical Database. Available at Web site: http://
faostat.fao.org/faostat/collections?version=ext&hasbulk=0&
subset=agriculture (4 December 2003).
20 Oerke, E.C., Dehne, H.W., Scho
¨
nbeck, F., and Weber, A.
1994. Crop Production and Crop Protection. Elsevier,
Amsterdam, NL.
21 Flint, M.L. 1998. Pests of the Garden and Small Farm.
University of California Press, Berkeley, CA.
22 Morales, H. 2002. Pest management in traditional tropical
agroecosystems: Lessons for pest prevention research and
extension. Integrated Pest Management Reviews 7:145–163.
23 Stanhill, G. 1990. The comparative productivity of organic
agriculture. Agriculture, Ecosystems and Environment 30:
1–26.
24 Leigh, R.A. and Johnson, A.E. 1994. Long-Term Experiments
in Agricultural and Ecological Sciences. CAB International,
Wallingford, UK.
25 Pimentel, D., Hepperly, P., Hanson, J., Douds, D., and Seidel,
R. 2005. Environmental, energetic and economic comparisons
of organic and conventional farming systems. BioScience
55:573–582.
26 Giller, K.E., McDonagh, J.F., and Cadisch, G. 1994. Can
biological nitrogen fixation sustain agriculture in the tropics?
In J.K. Syers and D.L. Rimmer (eds). Soil Science and
Sustainable Land Management in the Tropics. CAB Inter-
national, Wallingford, UK. p. 173–191.
27 Scialabba, N.El-H. and Hattam, C. (eds). 2002. Organic
Agriculture, Environment, and Food Security. Food and
Agriculture Organization of the United Nations, Rome, Italy.
28 Willer, H. and Yussefi, M. 2001. Organic Agriculture
Worldwide 2001: Statistics and Future Prospects. Foundation
for Ecology and Agriculture, Stuttgart, Germany.
29 Stark, P.B. 2004. SticiGui: statistics tools for internet and
classroom instruction with a graphic user interface. Avail-
able at Web site: http://stat-www.berkeley.edu/users/stark/
SticiGui/index.htm (8 August 2004).
30 Brady, N.C. and Weil, R.R. 2002. The Nature and Properties
of Soils. 13th ed. Prentice Hall, Upper Saddle River, NJ.
31 United States Geological Survey. 2003. Mineral Commodity
Summaries 2003. Government Printing Office, Washington,
DC.
32 Lampkin, N. 1994. Organic Farming. Farming Press,
Ipswich, UK.
33 Boddey, R.M., de Moraes, J.C., Alves, B.J.R., and Urquiaga,
S. 1997. The contribution of biological nitrogen fixation
for sustainable agriculture in the tropics. Soil Biology and
Biochemistry 29:787–799.
34 Hoyt, G.D. and Hargrove, W.L. 1986. Legume cover crops for
improving crop and soil management in the southern United
States. Horticultural Science 21:397–402.
35 United States Department of Agriculture (USDA). 1998.
National Agriculture Statistics. Available at Web site: http://
www.usda.gov/nass/pubs/agr98/acro98.htm
36 Galloway, J.N., Schlesinger, W.H., Levy II, H., Michaels, A.,
and Schnoor, J.L. 1995. Nitrogen fixation: anthropogenic
enhancement—environmental response. Global Biogeo-
chemical Cycles 9(2):235–252.
37 Vesterby, M. and Krupa, K.S. 1997. Major land uses in the
United States. Economic Research Service, United States
Department of Agriculture (USDA), USDA Statistical Bulletin
No. 973.
Organic agriculture and the global food supply 95
38 Center for Nutrition and Policy Promotion. 2000. Nutrition
and Your Health: Dietary Guidelines for Americans. 5th ed.
Home and Garden Bulletin No. 232. United States Department
of Agriculture and United States Department of Health and
Human Services, Washington, DC.
39 Uphoff, N. 2003. Higher yields with fewer external inputs?
The system of rice intensification and potential contributions
to agricultural sustainability. International Journal of Agri-
cultural Sustainability 1:38–50.
40 Sheehy, J.E., Peng, S., Dobermann, A., Mitchell, P.L., Ferrer,
A., Yang, J., Zou, Y., Zhong, Z., and Huang, J. 2004. Fantastic
yields in the system of rice intensification: fact or fallacy?
Field Crops Research 88:1–8.
41 Kumar, V., Mills, D.J., Anderson, J.D., and Mattoo, A.K.
2004. An alternative agriculture system is defined by a distinct
expression profile of select gene transcripts and proteins.
Proceedings of the National Academy of Sciences, USA
101:10535–10540.
42 Kramer, A., Doane, T., Horwath, W., and Kessel, C. 2002.
Combining fertilizer and organic inputs to synchronize N
supply in alternative cropping systems in California. Agri-
culture, Ecosystems and Environment 91:233–243.
43 Sustainable Agriculture Network. 1998. Managing Cover
Crops Profitably, 2nd ed. Sustainable Agriculture Network
Handbook Series 3, Beltsville, MD.
44 Radke, J.K., Liebhardt, W.C., Jahnke, R.R., and Peters, S.E.
1987. Legumes in crop rotations as an internal nitrogen
source for corn. In J.F. Power (ed.). Role of Legumes in
Conservation Tillage Systems. Soil Conservation Society of
America, Ankeny, IA. p. 56–57.
45 Dakora, F.D. and Keya, S.O. 1997. Contribution of legume
nitrogen fixation to sustainable agriculture in Sub-Saharan
Africa. Soil Biology and Biochemistry 29:809–817.
46 Sultan, K., Gintzburger, G., Obaton, M., Robin, C., Touchane,
H., and Guckert, A. 2001. Growth and nitrogen fixation
of annual Medicago–Rhizobium associations during winter
in Mediterranean region. European Journal of Agronomy
15:221–229.
47 Fahrney, K.S., El-Swaify, S.A., Lo, A.K.F., and Joy, R.J.
1987. Maize yields and soil loss with conservation and con-
ventional tillage practices on a tropical Aridisol. In J.F. Power
(ed.). Role of Legumes in Conservation Tillage Systems. Soil
Conservation Society of America, Ankeny, IA. p. 50–51.
48 Food and Agriculture Organization of the United Nations.
1993. Food and Agriculture Production Yearbook 1992.
Statistical Series 112. FAO, Rome, Italy.
49 Vandermeer, J.H. 1990. Intercropping. In C.R. Carroll, J.H.
Vandermeer, and P. Rosset (eds). Agroecology. McGraw Hill,
NY. p. 481–516.
50 Nair, P.K.R. 1984. Soil Productivity Aspects of Agroforestry:
Science and Practice in Agroforestry. International Council for
Research in Agroforestry, Nairobi.
51 Dobereiner, J. 1997. Biological nitrogen fixation in the tropics.
Soil Biology and Biochemistry 29:771–774.
52 Giller, K.E. and Wilson, K.J. 1991. Nitrogen Fixation in
Tropical Cropping Systems. CAB International, Wallingford,
UK.
53 Honeycutt, W.C., Clapham, W.M., and Leach, S.S. 1994.
A functional approach to efficient nitrogen use in crop
production. Ecological Modelling 73:51–61.
54 Drinkwater, L.E., Wagoner, P., and Sarrantonio, M. 1998.
Legume-based cropping systems have reduced carbon and
nitrogen losses. Nature 396:262–265.
55 Peoples, M.B. and Craswell, E.T. 1992. Biological nitrogen
fixation: investments, expectations and actual contributions to
agriculture. Plant and Soil 141:13–39.
56 Crews, T.E. and Peoples, M.B. 2004. Legume versus fertilizer
sources of nitrogen: ecological tradeoffs and human needs.
Agriculture, Ecosystems and Environment 102:279–297.
57 O’Hara, G.W., Howieson, J.G., and Graham, I.P.H. 2002.
Nitrogen fixation and agricultural practice. In G.J. Leigh (ed.).
Nitrogen Fixation at the Millennium. Elsevier, Amsterdam,
NL. p. 391–420.
58 Piper, J.K. 1998. Growth and seed yield of three perennial
grains within monocultures and mixed stands. Agriculture,
Ecosystems and Environment 68:1–11.
59 Rosset, P. 1999. The multiple functions and benefits of small
farm agriculture in the context of global trade negotiations.
Food First Policy Brief no. 4.
60 Pimentel, D. 1993. Economics and energetics of organic and
conventional farming. Journal of Agricultural and Environ-
mental Ethics 6:53–60.
61 Sorby, K. 2002. What is sustainable coffee? Background
Paper to the World Bank Agricultural Technology Note 30.
Washington, DC.
62 Granatstein, D. 2003. Tree fruit production with organic
farming methods. Wenatchee (WA) Center for Sustainable
Agriculture and Natural Resources, Washington State
University. Available at the Web site: http://organic.rfrec.
wsu.edu/OrganicIFP/OrganicFruitProduction/OrganicMgt.PDF
(26 April 2003).
63 Lampkin, N.H. and Padel, S. (eds) 1994. The Economics of
Organic Farming: An International Perspective. CAB Inter-
national, Wallingford, UK.
64 McDonald, A.J., Hobbs, P.R., and Riha, S.J. 2005. Does the
system of rice intensification outperform conventional best
management? A synopsis of the empirical record. Field Crops
Research 96:31–36.
65 Pretty, J. and Hine, R. 2001. Reducing food poverty with
sustainable agriculture: A summary of new evidence. Final
Report from the ‘SAFE World’ Research Project, University
of Essex. Available at Web site: http://www2.essex.ac.uk/
ces/ResearchProgrammes/SAFEWexecsummfinalreport.htm
(3 December 2003).
96 C. Badgley et al.
Appendix 1: Yield Ratios
The studies used to estimate the yield ratios for different
food categories in Table 1 come from 91 sources in
Table A1 describing results from experiments at research
stations, comparisons of paired farms, and comparisons
before and after the transition to organic production. The
data come from 53 countries and 12 US states. Some
comparisons during the transition to organic production
come from surveys, especially in the data for the
developing world. Data range in observation length from
one growing season to over 20 years. Despite the
observation that yields following conversion from conven-
tional to organic production initially decline and then tend
to increase over time
24
, we did not omit studies of short
duration so as not to bias estimates of relative yield. We
included data from previous comparisons of organic and
conventional production, notably Stanhill
23
, Lampkin and
Padel
63
, and McDonald et al.
64
for the SRI in the
developing world. Over 80% of the examples listed come
directly from peer-reviewed journal articles or are cited or
figured in them. The remainder come from technical books,
conference proceedings, technical reports from universities,
government agencies or independent research foundations,
or the Web site of a university research station.
For the developing world, there are fewer controlled
comparisons of organic versus non-organic methods than for
the developed world. Much of our data in Table A1B comes
from one source (Pretty and Hine
65
), which is a compilation
from surveys in developing countries of yield comparisons
before and after farmers adopted specific agroecological
practices. In order to determine whether the survey data
biased our results, we tested the hypothesis that the average
yield ratio based on survey data and unreported methods
differed significantly from the average yield ratio based on
experimental data and quantitative comparisons of paired
farms. The only food category with a substantial sample size
of yield ratios in both categories of studies was grains
(n = 102). We subdivided grains into rice and all other
grains, because more than half of our data concern rice but
these data are quite unequally distributed between the two
categories of studies. For rice (n = 61), a t-test (p = 0.55)
comparing the average yield ratios from surveys and
unreported methods versus experiments and paired farms
failed to reject the null hypothesis that the average yield
ratios do not differ significantly. For all other grains (n = 41),
a t-test (p = 0.45) also failed to reject the null hypothesis.
Thus, we concluded that the survey data have not unduly
biased our results for the developing world. (No data for the
developed world come from surveys.)
Table A1. Yield ratios of organic production : non-organic production, grouped by FAO food categories analyzed in the text. (A) Data
from developed countries, where comparisons are between organic and conventional (green-revolution) production methods. (B) Data
from developing countries, where comparisons are primarily between organic and non-intensive methods.
(A) Developed countries
Crop
Yield
ratio
Location Reference
Grains
Barley, summer 1.03 Germany Keopf, H.H., Pettersson, B.D., and Schaumann, W. 1976. Biodynamic Agriculture.
The Anthroposophic Press, Spring Valley, NY.
Barley, winter 1.14 Germany Keopf, H.H. et al. 1976. Op. cit.
Barley 0.68 New Zealand Nguyen, M.L. and Haynes, R.J. 1995. Energy and labour efficiency for three pairs of
conventional and alternative mixed cropping (pasture-arable) farms in
Canterbury, New Zealand. Agriculture, Ecosystems, and Environment
52:163–172.
Barley 0.78 Sweden Dlouhy, J. 1981. Alternative forms of agriculture—quality of plant products from
conventional and biodynamic growing. Report 91, Department of Plant
Husbandry, Swedish University of Agricultural Sciences, Uppsala.
Barley 0.65 Sweden Dlouhy, J. 1981. Op. cit.
Barley 0.75 Switzerland Eidg. Forschungsanstalt fu
¨
r Betriebswirtschaft und Landtechnik. 1993. Bericht u
¨
ber
biologisch bewirtschaftete Betriebe 1991. Ta
¨
nikon, Switzerland.
Barley 0.86 Switzerland Steinmann, R. 1983. Biological Agriculture—A Bookkeeping Comparison. Report
No. 19, Swiss Federal Research Station for Farm Management and Agricultural
Engineering, Ta
¨
nikon, Switzerland.
Corn, sweet 0.82 Canada,
Nova Scotia
Warman, P.R. and Havard, K.A. 1998. Yield, vitamin and mineral contents of
organically and conventionally grown potatoes and sweet corn. Agriculture,
Ecosystems and Environment 68:207–216.
Corn 1.16 Canada, Ontario Stonehouse, P. 1991. Economics of Weed Control in Alternative Farming Systems.
In Proceedings of the 5th REAP Conference. McGill University, Macdonald
Campus, Quebec.
Organic agriculture and the global food supply 97
Table A1. Continued.
Crop
Yield
ratio
Location Reference
Corn, sweet 0.60 Canada, Ontario Sellen, D., Tolman, J.H., McLeod, D., Weersink, A., and Yiridoe, E. 1993.
Economics of Organic and Conventional Horticulture Production. Working
Paper, Department of Agricultural Economics and Business, University of
Guelph, Guelph, Ontario.
Corn 0.89 Switzerland Steinmann, R. 1983. Op. cit.
Corn 0.94 US, 7 states Liebhardt, B. 2001. Get the facts straight: organic agriculture yields are good.
Organic Farming Research Foundation Information Bulletin 10, 1–5. Santa Cruz,
CA. Available at Web site: http://www.ofrf.org/publications/news/IB10.pdf
Corn 0.95 US, California Clark, M.S., Ferris, H., Klonsky, K., Lanini, W.T., van Bruggen, A.H.C., and
Zalom, F.G. 1998. Agronomic, economic, and environmental comparison of pest
management in conventional and alternative tomato and corn systems in northern
California. Agriculture, Ecosystems and Environment 68:51–71.
Corn 1.01 US, California Poudel, D.D., Horwath, W.R., Lanini, W.T., Temple, S.R., and van Bruggen,
A.H.C. 2002. Comparison of soil N availability and leaching potential, crop
yields and weeds in organic, low-input and conventional farming systems in
northern California. Agriculture, Ecosystems and Environment 90:125–137.
Corn 0.92 US, Iowa Delate, K. and Cambardella, C.A. 2004. Agroecosystem performance during
transition to certified organic grain production. Agronomy Journal 96:1288–1298.
Corn 0.92 US, midwest Lockeretz, W., Shearer, G., and Kohl, D.H. 1981. Organic farming in the corn belt.
Science 211:540–547.
Corn 0.91 US, Minnesota Porter, P., Huggins, D., Perillo, C., Quiring, S., and Crookston, R. 2003. Organic
and other management strategies with two- and four-year crop rotations in
Minnesota. Agronomy Journal 95:233–244.
Corn 0.92 US, Nebraska Sahs, W.W., Lesoing, G.W., and Francis, C.A. 1992. Rotation and manure effects
on crop yields and soil characteristics in eastern Nebraska. Agronomy Abstracts
84:155.
Corn 0.93 US, New Jersey Brumfield, R.G., Rimal, A., and Reiners, S. 2000. Comparative cost analyses of
conventional, integrated crop management, and organic methods.
HortTechnology 10:785–793.
Corn 1.30 US, Ohio National Research Council. 1989. Alternative Agriculture. National Academy Press,
Washington, DC.
Corn 1.17 US, Pennsylvania National Research Council. 1989. Op. cit.
Corn 0.86 US, Pennsylvania Pimentel, D., Hepperly, P., Hanson, J., Douds, D., and Seidel, R. 2005.
Environmental, energetic, and economic comparisons of organic and
conventional farming systems. Bioscience 55:573–582.
Corn 0.89 US, Pennsylvania Pimentel, D. et al. 2005. Op. cit.
Corn 0.84 US, South Dakota Smolik, J.D., Dobbs, T.L., and Rickerl, D.H. 1995. The relative sustainability
of alternative, conventional, and reduced-till farming systems. American Journal
of Alternative Agriculture 10:25–35.
Corn 0.95 US, South Dakota Dobbs, T. and Smolik, J.D. 1996. Productivity and profitability of conventional and
alternative farming systems: A long-term on-farm paired comparison. Journal of
Sustainable Agriculture 9:63–77.
Corn 1.04 US, western
corn belt
Roberts, K.J., Warnken, F., and Schneeberger, K.C. 1979. The economics of organic
crop production in the Western corn belt. Agricultural Economics Paper No.
1979-6. Department of Agricultural Economics, University of Missouri,
Columbia, MO. p. 63–101.
Grains 1.24 Germany Keopf, H.H. 1981. The principles and practice of biodynamic agriculture. In
B. Stonehouse (ed.). Biological Husbandry. Butterworths, London. p. 237–250.
Oats 1.21 Germany Koepf, H.H. et al. 1976, Op. cit.
Oats 0.85 Switzerland Steinmann, R. 1983, Op. cit.
Oats 1.00 US, midwest Lockeretz, W. et al. 1981. Op. cit.
Oats 1.23 US, Ohio National Research Council. 1989. Op. cit.
Oats 0.73 US, western
corn belt
Roberts, K.J. et al. 1979. Op. cit.
Oats 0.85 UK Trewavas, A. 2004. A critical assessment of organic farming-and-food assertions
with particular respect to the UK and the potential environmental benefits of
no-till agriculture. Crop Protection 23:757–781.
98 C. Badgley et al.
Table A1. Continued.
Crop
Yield
ratio
Location Reference
Rice 0.85 Spain Scialabba, N. El-H. and Hattam, C. (eds). 2002. Organic Agriculture, Environment,
and Food Security. FAO, Rome.
Rye 1.26 Germany Koepf, H.H. et al. 1976. Op. cit.
Rye 0.94 Germany Raupp, J. 1996. Quality investigations with products of the long-term fertilization
trial in Darmstadt. In J. Raupp (ed.). Quality of Plant Products Grown with
Manure Fertilization. Vol. 9. Institute for Biodynamic Research, Darmstadt.
p. 13–33.
Rye 0.96 Germany Raupp, J. 1996. Op. cit.
Rye 0.75 Germany Raupp, J. 1996. Op. cit.
Rye 0.78 Germany Raupp, J. 1996. Op. cit.
Rye 0.81 Switzerland Eidg. Forschungsanstalt fu
¨
r Betriebswirtschaft und Landtechnik. 1993. Op. cit.
Wheat 0.96 Australia Wynen, E. 1994. Economics of organic farming in Australia. In N.H. Lampkin
and S. Padel (eds). The Economics of Organic Farming: An International
Perspective, CAB International, Wallingford, UK. p. 185–199.
Wheat 1.45 Australia Leu, A. 2004. Organic agriculture can feed the world. Acres USA. January 2004.
Wheat, winter 1.14 Canada, Ontario Stonehouse, P. 1991. Op. cit.
Wheat 1.12 Germany Koepf, H.H. et al. 1976. Op. cit.
Wheat, spring 1.01 Germany Raupp, J. 1996. Op. cit.
Wheat, spring 1.02 Germany Raupp, J. 1996. Op. cit.
Wheat, Oats,
Rye
1.00 Germany Dabbert, S. 1990. Zur Optimalen Organisation Alternativer Landwirtschaftlicher
Betriebe. Agrarwirtschaft Sonderheft 124. Verlag Alfred Strothe, Frankfurt.
Wheat 1.09 Israel Levi, M. 1979. Principle of bio-organic agriculture. The Biosphere 8:30–35.
Wheat 0.68 New Zealand Nguyen, M.L. and Haynes, R.J. 1995. Op. cit.
Wheat 0.88 Sweden, Jarna Granstedt, A.G. and Kjellenberg, L. 1996. Quality investigations with the K-trial,
Jarna, and other Scandinavian fertilization experiments. In J. Raupp (ed.). Quality
of Plant Products Grown with Manure Fertilization. Vol. 9. Institute for
Biodynamic Research. Darmstadt. p. 3–12.
Wheat 0.80 Sweden, Uppsala Granstedt, A.G. and Kjellenberg, L. 1996. Op. cit.
Wheat 0.77 Switzerland Eidg. Forschungsanstalt fu
¨
r Betriebswirtschaft und Landtechnik. 1993. Op. cit.
Wheat 0.86 Switzerland Steinmann, R. 1983. Op. cit.
Wheat 0.87 Switzerland Ma
¨
der, P., Fleißbach, A., Dubois, D., Gunst, L., Fried, P. and Niggli, U. 2002. Soil
fertility and biodiversity in organic farming. Science 296:1694–1697.
Wheat 0.98 US, California McGuire, A.M., Bryant, D.C., and Denison, R.F. 1998. Wheat yields, nitrogen
uptake, and soil moisture following winter legume cover crop vs. fallow.
Agronomy Journal 90:404–410.
Wheat 0.96 US, California McGuire, A.M. et al. 1998. Op. cit.
Wheat 0.83 US, California McGuire, A.M. et al. 1998. Op. cit.
Wheat 0.81 US, California McGuire, A.M. et al. 1998. Op. cit.
Wheat 0.56 US, Michigan Kellogg Biological Station Long Term Ecological Research, http://lter.kbs.msu.edu.
Wheat 0.55 US, Michigan Kellogg Biological Station Long Term Ecological Research, http://lter.kbs.msu.edu.
Wheat 0.57 US, midwest Lockeretz, W. et al. 1981. Op. cit.
Wheat 0.78 US, New York,
Pennsylvania
Berardi, G.M. 1978. Organic and conventional wheat production: Examination
of energy and economics. Agro-Ecosystems 4:367–376.
Wheat 1.05 US, Ohio National Research Council. 1989. Op. cit.
Wheat 1.00 US, Pennsylvania National Research Council. 1989. Op. cit.
Wheat 1.09 US, South Dakota Smolik, J.D. et al. 1995. Op. cit.
Wheat 0.97 US, South Dakota,
Michigan
Liebhardt, B. 2001. Op. cit.
Wheat 1.00 US, western
corn belt
Roberts, K.J. et al. 1979. Op. cit.
Wheat 1.15 UK Jenkinson, D.S., Bradbury, N.J., and Coleman, K. 1994. In R.A. Leigh and
A.E. Johnston (eds). Long-term Experiments in Agricultural and Ecological
Sciences. CAB International, Wallingford, UK. p. 117–138.
Wheat 0.68 UK Trewavas, A. 2004. Op. cit.
Starchy roots
Potatoes 0.85 Canada,
Nova Scotia
Warman, P.R. and Havard, K.A. 1998. Op. cit.
Organic agriculture and the global food supply 99
Table A1. Continued.
Crop
Yield
ratio
Location Reference
Potatoes 1.18 Germany Koepf, H.H. et al. 1976. Op. cit.
Potatoes 0.90 Germany Raupp, J. 1996. Op. cit.
Potatoes 0.96 Germany Raupp, J. 1996. Op. cit.
Potatoes 0.96 Germany Raupp, J. 1996. Op. cit.
Potatoes 1.06 Germany Raupp, J. 1996. Op. cit.
Potatoes 1.00 Israel Levi, M. 1979. Op. cit.
Potatoes 0.86 Sweden Dlouhy, J. 1981. Op. cit.
Potatoes 0.69 Sweden Dlouhy, J. 1981. Op. cit.
Potatoes 0.82 Sweden, Jarna Granstedt, A.G. and Kjellenberg, L. 1996. Op. cit.
Potatoes 0.81 Sweden, Uppsala Granstedt, A.G. and Kjellenberg, L. 1996. Op. cit.
Potatoes 0.62 Switzerland Ma
¨
der, P. et al. 2002. Op. cit.
Potatoes 0.74 Switzerland Eidg. Forschungsanstalt fu
¨
r Betriebswirtschaft und Landtechnik. 1993. Op. cit.
Potatoes 1.03 Switzerland Steinmann, R. 1983. Op. cit.
Sugars and sweeteners
Sugar beet 1.02 Germany Koepf, H.H. et al. 1976. Op. cit.
Sugar beet 0.99 Israel Levi, M. 1979. Op. cit.
Legumes (Pulses)
Beans, bush 0.83 Germany Lindner, U. 1987. Alternativer Anbau–eine Alternative fu
¨
r den Erwerbsgemu
¨
sebau
Gartenbauliche Versuchsberichte der Landwirtschaftkammer Rheinland
5:106–109.
Beans, dry 1.17 US, Maine Eggert, F.M. 1983. Effect of soil management practices on yield and foliar nutrient
concentration of dry beans, carrots and tomatoes. In W. Lockeretz (ed.).
Environmentally Sound Agriculture. Praeger, New York. p. 247–259.
Beans, green 0.90 Canada, Ontario Sellen, D. et al. 1993. Op. cit.
Beans, runner 0.65 Germany Lindner, U. 1987. Op. cit.
Beans, winter 0.72 UK Trewavas, A. 2004. Op. cit.
Peas 0.83 New Zealand Nguyen, M.L. and Haynes, R.J. 1995. Op. cit.
Peas, dried 0.61 UK Trewavas, A. 2004. Op. cit.
Oil crops
Soybeans 0.94 US, 5 states Liebhardt, B. 2001. Op. cit.
Soybeans 1.01 US, Iowa Delate, K. and Cambardella, C.A. 2004. Op. cit.
Soybeans 0.95 US, midwest Lockeretz, W. et al. 1981. Op. cit.
Soybeans 0.81 US, Minnesota Porter, P. et al. 2003. Op. cit.
Soybeans 1.39 US, Ohio National Research Council. 1989. Op. cit.
Soybeans 1.00 US, Pennsylvania Hanson, J.C., Lichtenberg, E., and Peters, S.E. 1997. Organic versus conventional
grain production in the mid-Atlantic: an economic and farming system overview.
American Journal of Alternative Agriculture 12:2–9.
Soybeans 1.26 US, Pennsylvania National Research Council. 1989. Op. cit.
Soybeans 0.97 US, Pennsylvania Pimentel, D. et al. 2005. Op. cit.
Soybeans 0.88 US, Pennsylvania Pimentel, D. et al. 2005. Op. cit.
Soybeans 1.00 US, South Dakota Smolik, J.D. et al. 1995. Op. cit.
Soybeans 1.03 US, South Dakota Smolik, J.D. et al. 1995. Op. cit.
Soybeans 0.77 US, South Dakota Dobbs, T. and Smolik, J.D. 1996. Op. cit.
Soybeans 0.87 US, western
corn belt
Roberts, K.J. et al. 1979. Op. cit.
Vegetables
Beetroot 1.01 Germany Raupp, J. 1996. Op. cit.
Beetroot 1.06 Germany Raupp, J. 1996. Op. cit.
Beetroot 0.91 Germany Lindner, U. 1987. Op. cit.
Cabbage 0.98 Canada,
Nova Scotia
Warman, P.R. and Havard, K.A. 1997. Op. cit.
Cabbage 0.81 Canada, Ontario Sellen, D. et al. 1993. Op. cit.
Cabbage 0.67 Germany Lindner, U. 1987. Op. cit.
Carrots 1.06 Canada,
Nova Scotia
Warman, P.R. and Havard, K.A. 1997. Yield, vitamin and mineral contents
of organically and conventionally grown carrots and cabbage. Agriculture,
Ecosystems and Environment 61:155–162.
100 C. Badgley et al.
Table A1. Continued.
Crop
Yield
ratio
Location Reference
Carrots 1.04 Germany Raupp, J. 1996. Op. cit.
Carrots 1.08 Germany Raupp, J. 1996. Op. cit.
Carrots 0.97 Israel Levi, M. 1979. Op. cit.
Carrots 0.95 US, Maine Eggert, F.M. 1983. Op. cit.
Cauliflower 0.64 Germany Lindner, U. 1987. Op. cit.
Celeriac 0.96 Germany Lindner, U. 1987. Op. cit.
Endive 0.80 Germany Lindner, U. 1987. Op. cit.
Fennel 0.76 Germany Lindner, U. 1987. Op. cit.
Kohlrabi 0.84 Germany Lindner, U. 1987. Op. cit.
Leeks 0.92 Germany Lindner, U. 1987. Op. cit.
Lettuce 0.76 Germany Lindner, U. 1987. Op. cit.
Onions, Spanish 0.78 Canada, Ontario Sellen, D. et al. 1993. Op. cit.
Savoy 0.83 Germany Lindner, U. 1987. Op. cit.
Spinach 0.65 Germany Lindner, U. 1987. Op. cit.
Tomatoes 0.55 Canada, Ontario Sellen, D. et al. 1993. Op. cit.
Tomatoes 1.00 US, California Liebhardt, B. 2001. Op. cit.
Tomatoes 0.83 US, California Clark, M.S. et al. 1998. Op. cit.
Tomatoes 0.89 US, California Clark, M.S. et al. 1998. Op. cit.
Tomatoes 0.97 US, California Poudel, D.D. et al. 2002. Op. cit.
Tomatoes 1.00 US, California Drinkwater, L.E. et al. 1995. Op. cit.
Tomatoes 1.04 US, Maine Eggert, F.M. 1983. Op. cit.
Vegetables 0.68 Canada Parsons, W. 2002. Organic fruit and vegetable production: Is it for you? Vista:
Statistics Canada; Agriculture Division.
Vegetables 0.71 UK Department for Environment, Food, and Rural Affairs (DEFRA). 2002.
www.hdra.org.uk/pdfs/Conversion_report_2001-2002.pdf.
Vegetables, leafy 1.00 Japan Xu, H.L., Wang, R., Xu, R.Y., Mridha, M.A.U., and Goyal, S. 2003. Yield
and quality of leafy vegetables grown with organic fertilizations. Acta
Horticulturae 627:25–33.
Fruits
Apples 1.00 US, Washington Reganold, J.P., Glover, J.D., Andrews, P.K., and Hinman, J.R. 2001. Sustainability
of three apple production systems. Nature 410:926–930.
Fruits 0.91 Canada Parsons, W. 2002. Op. cit.
Meat and offals
Beef, bull 1.01 Germany Lo
¨
lau, S. and Zerger, U. 1989, 1991. Datenauswertung im Rahmen des
Agrarkulturpreises der KLS-Stiftung. Munich (cited in Lampkin, N.H. and
Padel, S. (eds). 1994. Op. cit.)
Beef, milk cows 1.07 Germany Koepf, H.H. et al. 1976. Op. cit.
Beef 1.01 UK Younie, D., Watson, C., Halliday, G., Armstrong, G., Slee, W., and Daw, M. 1990.
Organic Beef in Practice. Scottish Agricultural College, Aberdeen.
Chicken, broiler 0.86 Italy Castellini, C., Mugnai, C., and Dal Bosco, M. 2002. Effect of organic
production system on broiler carcass and meat quality. Meat Science
60:219–225.
Lamb 0.86 Italy Morbidini, L., Sarti, D.M., Pollidori, P., and Valigi, A. 1999. Carcass, meat and
fat quality in Italian Merino derived lambs obtained with ‘organic’ farming
systems. FAO-CIHEAM Network. http://ressources.ciheam.org/om/pdf/a46/
01600108.pdf
Pork 1.11 Germany Lo
¨
lau, S. and Zerger, U. 1989, 1991. Op. cit.
Pork 0.98 Germany Sundrum, A., Bu
¨
tfering, L., Henning, M., and Hoppenbrock, K.H. 2000. Effects of
on-farm diets for organic pig production on performance and carcass quality.
Journal of Animal Science 78:1199–1205.
Pork 1.00 Sweden Olsson, V., Andersson, K., Hansson, I., and Lundstro
¨
m, K. 2003. Differences in
meat quality between organically and conventionally produced pigs. Meat
Science 64:287–297.
Milk, excl. butter
Milk 1.06 Australia Dornom, H. and Tribe, D.E. 1976. Energetics of dairying in Gippsland. Search
7:431–433.
Organic agriculture and the global food supply 101
Table A1. Continued.
Crop
Yield
ratio
Location Reference
Milk 0.80 Canada, Quebec Burgoyne, D. 1992. Analyse e
´
conomique compare
´
e de l’impact du niveau
d’intensification, de l’utilisation d’intrants et de la production biologique sur la
rentabilite
´
des enterprises laitie
`
res au Que
´
bec. MSc thesis, FSAA, Universite
´
Laval, Quebec.
Milk 0.98 Denmark Kristensen, T. and Kristensen, E.S. 1998. Analysis and simulation modelling of
the production in Danish organic and conventional dairy herds. Livestock
Production Science 54:55–65.
Milk 0.95 Denmark Refsgaard, K., Halberg, N., and Kristensen, E.S. 1998. Energy utilization in crop
and dairy production in organic and conventional livestock production systems.
Agricultural Systems 57:599–630.
Milk 0.90 Germany Winter, R. 1991. Economic questions of dairy production in ecological agriculture
in northern Germany. In E. Boehncke and V. Molkenthin (eds). Alternatives in
Animal Husbandry. Proceedings of the International Conference, July 1991.
University of Kassel, Witzenhausen, Germany.
Milk 0.78 Germany Haas, G., Wetterich, F., and Ko
¨
pke, U. 2001. Comparing intensive, extensified and
organic grassland farming in southern Germany by process life cycle assessment.
Agriculture, Ecosystems and Environment 83:43–53.
Milk 1.29 Germany Koepf, H.H. 1981. Op. cit.
Milk 0.78 Norway Reksen, O., Tverdal, A., and Ropstad, E. 1999. A comparative study of reproductive
performance in organic and conventional dairy husbandry. Journal of Dairy
Science 82:2605–2610.
Milk 0.91 Sweden Cederberg, C. and Mattsson, B. 2000. Life cycle assessment of milk production—a
comparison of conventional and organic farming. Journal of Cleaner Production
8:49–60.
Milk 0.99 Switzerland Eidg. Forschungsanstalt fu
¨
r Betriebswirtschaft und Landtechnik. 1993. Op. cit.
Milk 1.00 UK Haggar, R. and Padel, S. 1996. Conversion to Organic Milk Production, Institute
of Grassland and Environmental Research (IGER) Technical Review no. 4,
Aberystwyth, UK.
Milk 0.91 UK Houghton, M. and Poole, A.H. 1990. Organic Milk Production. Genus Information
Unit Report 70. Genus Management, Wrexham, UK.
Milk 0.99 UK Padel, S. 2000. Strategies of organic milk production. In M. Hovi and M. Bouilhol
(eds). Human-animal Relationship: Stockmanship and Housing in Organic
Livestock Systems, Proceedings of the 3rd NAHWOA (Network for Animal
Health and Welfare in Organic Agriculture) Workshop. p. 121–135. Available at
Web site: http://www.veeru.reading.ac.uk/organic/ProceedingsFINAL.pdf
Eggs
Eggs 1.06 Germany Lo
¨
lau, S. and Zerger, U. 1989, 1991. Op. cit.
(B) Developing countries
Crop
Yield
ratio
Location Reference
Grains
Barley 1.43 Peru Altieri, M. 1999. Applying agroecology to enhance the productivity of peasant
farming systems in Latin America. Environment, Development and Sustainability
1:197–217.
Maize 1.37 Argentina Pretty, J. and Hine, R. 2001. Reducing food poverty with sustainable agriculture: a
summary of new evidence. Centre for Environment and Society, Essex University.
Available at Web site: http://www2.essex.ac.uk/ces/ResearchProgrammes/
CESOccasionalPapers/SAFErepSUBHEADS.htm
Maize 1.30 Benin Pretty, J. and Hine, R. 2001. Op. cit.
Maize 1.31 Brazil Pretty, J. and Hine, R. 2001. Op. cit.
Maize 1.20 Brazil Altieri, M. 2001. Applying agroecology to enhance the productivity of peasant
farming systems in Latin America. Paper presented to Conference, Reducing
Poverty through Sustainability, Saint James Palace, London.
Maize 3.50 Brazil Altieri, M. 2001. Op. cit.
102 C. Badgley et al.
Table A1. Continued.
Crop
Yield
ratio
Location Reference
Maize 2.78 China Pretty, J. and Hine, R. 2001. Op. cit.
Maize 1.38 China Pretty, J. and Hine, R. 2001. Op. cit.
Maize 1.09 China Pretty, J. and Hine, R. 2001. Op. cit.
Maize 1.71 Colombia Pretty, J. and Hine, R. 2001. Op. cit.
Maize 3.71 Guatemala Pretty, J. and Hine, R. 2001. Op. cit.
Maize 3.00 Honduras Pretty, J. and Hine, R. 2001. Op. cit.
Maize 2.28 Honduras Pretty, J. and Hine, R. 2001. Op. cit.
Maize 2.00 Kenya Pretty, J. and Hine, R. 2001. Op. cit.
Maize 3.49 Kenya Pretty, J. and Hine, R. 2001. Op. cit.
Maize 1.46 Kenya Pretty, J. and Hine, R. 2001. Op. cit.
Maize 1.50 Malawi Pretty, J. and Hine, R. 2001. Op. cit.
Maize 1.33 Nepal Pretty, J. and Hine, R. 2001. Op. cit.
Maize 3.14 Nicaragua Pretty, J. and Hine, R. 2001. Op. cit.
Maize 1.71 Niger Pretty, J. and Hine, R. 2001. Op. cit.
Maize 2.22 Paraguay Pretty, J. and Hine, R. 2001. Op. cit.
Maize 1.65 Peru Altieri, M. 1999. Op. cit.
Maize 2.50 Peru Altieri, M. 2001. Op. cit.
Maize 1.20 Philippines Pretty, J. and Hine, R. 2001. Op. cit.
Maize 3.27 Philippines Pretty, J. and Hine, R. 2001. Op. cit.
Maize 1.26 Sri Lanka Scialabba, N. El-H. and Hattam, C. (eds). 2003. Op cit..
Maize 2.00 Tanzania Pretty, J. and Hine, R. 2001. Op. cit.
Millet 1.73 Ethiopia Pretty, J. and Hine, R. 2001. Op. cit.
Rice 1.08 Bangladesh Pretty, J. and Hine, R. 2001. Op. cit.
Rice 1.12 China Pretty, J. and Hine, R. 2001. Op. cit.
Rice 1.08 Indonesia Pretty, J. and Hine, R. 2001. Op. cit.
Rice 1.00 Sri Lanka Pretty, J. and Hine, R. 2001. Op. cit.
Rice 1.28 Sri Lanka Pretty, J. and Hine, R. 2001. Op. cit.
Rice 1.09 Vietnam Pretty, J. and Hine, R. 2001. Op. cit.
Rice, SRI 0.93 Bangladesh Latif, M.A., Islam, M.R., Ali, M.Y., and Saleque, M.A. 2005. Validation of the system
of rice intensification (SRI) in Bangladesh. Field Crops Research 93:281–292.
Rice, SRI 0.84 Bangladesh Latif, M.A. et al. 2005. Op. cit.
Rice, SRI 1.17 Bangladesh Latif, M.A. et al. 2005. Op. cit.
Rice, SRI 0.89 Bangladesh Latif, M.A. et al. 2005. Op. cit.
Rice, SRI 1.18 Bangladesh Latif, M.A. et al. 2005. Op. cit.
Rice, SRI 1.29 Madagascar Barison, J. 2002. Evaluation of nutrient uptake and nutrient-use efficiency of SRI
and conventional rice cultivation methods in Madagascar. In N. Uphoff,
E.C.F. Fernandes, L.P. Yuan, J. Peng, S. Rafaralahy, and J. Rabenandrasana (eds).
Assessments of the System of Rice Intensification (SRI): Proceedings of an
International Conference, Sanya, China, CIIFAD, Ithaca, NY. p. 143–147.
Rice, SRI 1.20 Bangladesh BRRI (http://ciifad.cornell.edu/sri/countries/bangladesh/bangrisrifnl.pdf), cited in
McDonald, A.J., Hobbs, P.R., and Riha, S.J. 2005. Does the system of rice
intensification outperform conventional best management? A synopsis of the
empirical record. Field Crops Research 96:31–36.
Rice, SRI 1.22 China Shengfu, A., Xiehui, W., Zhongjiong, X., Shixiu, X., Chengquan, L., and Yangchang,
L. 2002. Assessment of using SRI with the super hybrid rice variety Liangyoupei 9.
In N. Uphoff et al. (eds). Op. cit. p. 112–115.
Rice, SRI 1.19 India MSSRF (http://ciifad.cornell.edu/sri/countries/india/), cited in McDonald, A.J. et al.
2005. Op. cit.
Rice, SRI 1.11 Laos Welthungerhilfe (http://ciifad.cornell.edu/sri/countries/laos/laoritr102.pdf), cited in
McDonald, A.J. et al. 2005. Op. cit.
Rice, SRI 1.10 Sri Lanka Nissanka, S. and Bandara, T. 2004. Comparison of productivity of system of rice
intensification and conventional rice farming systems in the dry-zone region of
Sri Lanka. Fourth International Crop Science Congress (ICSC2004). Available at
Web site: http://www.cropscience.org.au/icsc2004/poster/1/2/1177_nissankara.htm
Rice, SRI 1.09 China Sheehy, J.E., Peng, S., Dobermann, A., Mitchell, P.L., Ferrer, A., Jianchang, Y., Zou,
Y., Zhong, X., and Huang, J. 2004. Fantastic yields in the system of rice
intensification: fact or fallacy? Field Crops Research 88:1–8.
Organic agriculture and the global food supply 103
Table A1. Continued.
Crop
Yield
ratio
Location Reference
Rice, SRI 1.09 Indonesia Markarim, A.K., Balasubramanian, V., Zaini, Z., Syamsiah, I., Diratmadja, I.G.P.A.,
Arafah, H., Wardana, I.P., and Gani, A. 2002. System of rice intensification (SRI):
Evaluation of seedling age and selected components. In B.A. Bouman,
H. Hengsdijk, B. Hardy, P.S. Bindraban, T.P. Tuong, and J.K. Ladha (eds).
Water-wise Rice Production, Proceedings of International Workshop on
Water-Wise Rice Production, International Rice Research Institute. Los Banos,
Phillipines, p. 356.
Rice, SRI 1.02 China Qingquan, Y. 2002. The system of rice intensification and its use with hybrid rice
varieties in China. In N. Uphoff et al. (eds). Op. cit. p. 109–111.
Rice, SRI 1.02 China Shao-hua, W., Weixing, C., Dong, J., Tingbo, D., and Yan, Z. 2002. Physiological
characteristics and high-yield techniques with SRI rice. In N. Uphoff et al. (eds).
Op. cit. p. 116–124.
Rice, SRI 1.02 China Shao-hua, W. et al. 2002. Op. cit.
Rice, SRI 1.02 Bangladesh Duxbury, J.M., cited in McDonald, A.J. et al. 2005. Op. cit.
Rice, SRI 0.99 China Sheehy, J.E. et al. 2004. Op. cit.
Rice, SRI 0.95 Nepal Evans, C., Justice, S., and Shrestha, S. 2002. Experience with the system of rice
intensification in Nepal. In N. Uphoff et al. (eds). Op. cit. p. 64–66.
Rice, SRI 0.95 China Shao-hua, W. et al. 2002. Op. cit.
Rice, SRI 0.94 China Shao-hua, W. et al. 2002. Op. cit.
Rice, SRI 0.93 China Shao-hua, W. et al. 2002. Op. cit.
Rice, SRI 0.92 Bangladesh Duxbury, J.M., cited in McDonald, A.J. et al. 2005. Op. cit.
Rice, SRI 0.91 China Sheehy, J.E. et al. 2004. Op. cit.
Rice, SRI 0.90 Thailand Gypmantasiri, P. 2002. Experience with the system of rice intensification in northern
Thailand. In N. Uphoff et al. (eds). Op. cit. p. 75–79.
Rice, SRI 0.86 Laos DED (http://ciifad.cornell.edu/sri/countries/laos/laoritr102.pdf)
Rice, SRI 0.83 Bangladesh Duxbury, J.M., cited in McDonald, A.J. et al. 2005. Op. cit.
Rice, SRI 0.82 Bangladesh Duxbury, J.M., cited in McDonald, A.J. et al. 2005. Op. cit.
Rice, SRI 0.73 Philippines Rickman, J.F. 2004. Preliminary results: Rice production and the system of rice
intensification. Available at Web site: http://ciifad.cornell.edu/sri/countries/
philippines/irrieval.pdf
Rice, SRI 0.73 India Annapurna farm (http://ciifad.cornell.edu/sri/countries/india/)
Rice, SRI 0.64 Thailand Sooksa-nguan, T., Teaumroong, N., Boonkerd, N., Gypmantasiri, P., and Thies, J.E.
2004. Microbial community activity and structure associated with the system of rice
intensification in northern Thailand. In: Soil Science Society of America, 68th
Annual Meeting, Seattle, WA.
Rice, SRI 0.63 Laos GTZ (http://ciifad.cornell.edu/sri/countries/laos/laoritr102.pdf)
Rice, SRI 0.62 Thailand Gypmantasiri, P. 2002. Op. cit.
Rice, SRI 0.80 Bangladesh Duxbury, J.M., cited in McDonald, A.J. et al. 2005. Op. cit.
Rice, SRI 0.75 Nepal Duxbury, J.M., cited in McDonald, A.J. et al. 2005. Op. cit.
Rice, SRI 0.60 Thailand Gypmantasiri, P. 2002. Op. cit.
Rice, SRI 0.45 Philippines Rickman, J.F. 2004. Op. cit.
Rice, SRI 0.39 Laos NRRP (http://ciifad.cornell.edu/sri/countries/laos/laoritr102.pdf)
Rice, SRI 1.29 Bangladesh Uphoff, N. 2003. Higher yields with fewer external inputs? The system of rice
intensification and potential contributions to agricultural sustainability.
International Journal of Agricultural Sustainability 1:38–50.
Rice, SRI 1.78 Cambodia Uphoff, N. 2003. Op. cit.
Rice, SRI 1.14 China Uphoff, N. 2003. Op. cit.
Rice, SRI 1.58 Cuba Uphoff, N. 2003. Op. cit.
Rice, SRI 3.09 Gambia Uphoff, N. 2003. Op. cit.
Rice, SRI 1.48 Indonesia Uphoff, N. 2003. Op. cit.
Rice, SRI 2.77 Madagascar Uphoff, N. 2003. Op. cit.
Rice, SRI 2.95 Madagascar Uphoff, N. 2003. Op. cit.
Rice, SRI 2.00 Philippines Uphoff, N. 2003. Op. cit.
Rice, SRI 2.12 Sierra Leone Uphoff, N. 2003. Op. cit.
Rice, SRI 2.17 Sri Lanka Uphoff, N. 2003. Op. cit.
Rice, upland 2.80 India Pretty, J. and Hine, R. 2001. Op. cit.
Rice, upland 1.87 India Pretty, J. and Hine, R. 2001. Op. cit.
104 C. Badgley et al.
Table A1. Continued.
Crop
Yield
ratio
Location Reference
Rice, upland 3.40 Nepal Pretty, J. and Hine, R. 2001. Op. cit.
Rice, upland 1.50 Nepal Pretty, J. and Hine, R. 2001. Op. cit.
Rice, upland 1.23 Pakistan Wai, O.K. 1995. Food, culture, trade and the environment in Asia. Ecology and
farming (published by International Federation of Organic Agriculture Movements)
10:22–26.
Rice, upland 1.13 Philippines Pretty, J. and Hine, R. 2001. Op. cit.
Sorghum 1.65 India Pretty, J. and Hine, R. 2001. Op. cit.
Sorghum/Millet 2.10 Burkina Faso Pretty, J. and Hine, R. 2001. Op. cit.
Sorghum/Millet 3.50 India Pretty, J. and Hine, R. 2001. Op. cit.
Sorghum/Millet 1.76 India Pretty, J. and Hine, R. 2001. Op. cit.
Sorghum/Millet 2.12 India Pretty, J. and Hine, R. 2001. Op. cit.
Sorghum/Millet 2.25 India Pretty, J. and Hine, R. 2001. Op. cit.
Sorghum/Millet 5.67 Mali Pretty, J. and Hine, R. 2001. Op. cit.
Sorghum/Millet 1.71 Niger Pretty, J. and Hine, R. 2001. Op. cit.
Sorghum/Millet 2.35 Senegal Pretty, J. and Hine, R. 2001. Op. cit.
Sorghum/Teff 1.50 Ethiopia Pretty, J. and Hine, R. 2001. Op. cit.
Wheat 1.17 China Pretty, J. and Hine, R. 2001. Op. cit.
Wheat 1.17 Pakistan Pretty, J. and Hine, R. 2001. Op. cit.
Wheat 1.25 Pakistan Wai, O.K. 1995. Op. cit.
Starchy roots
Cassava 1.30 Cuba Ruiz, L. 1993. Factores que condicionan la eficiencia de las micorrizas arbusculares,
como alternativa para la fertilizacio
´
n de las raı
´
ces y tube
´
rculos tropicales.
Dissertation, Agricultural University of Havana (UNAH), Havana.
Cassava 1.75 Ghana Pretty, J. and Hine, R. 2001. Op. cit.
Potatoes 1.50 Bolivia Pretty, J. and Hine, R. 2001. Op. cit.
Potatoes 3.50 Bolivia Pretty, J. and Hine, R. 2001. Op. cit.
Potatoes 1.43 Peru Altieri, M. 1999. Op. cit.
Potatoes 3.08 Peru Pretty, J. and Hine, R. 2001. Op. cit.
Potatoes 4.40 Peru Pretty, J. and Hine, R. 2001. Op. cit.
Potatoes 1.60 Peru Pretty, J. and Hine, R. 2001. Op. cit.
Sweet Potato 5.83 Ethiopia Pretty, J. and Hine, R. 2001. Op. cit.
Sweet Potato 3.78 Indonesia Pretty, J. and Hine, R. 2001. Op. cit.
Sweet Potato 1.50 Indonesia Pretty, J. and Hine, R. 2001. Op. cit.
Legumes (pulses)
Beans 5.67 Honduras Bunch, R. 1999. More productivity with fewer external inputs: Central American case
studies of agroecological development and their broader implications. Environment,
Development and Sustainability 1:219–233.
Beans 2.32 Honduras Pretty, J. and Hine, R. 2001. Op. cit.
Oil crops
Peanut 1.64 Senegal Altieri, M. and Uphoff, N. 2001. Alternatives to conventional modern agriculture for
meeting food needs in the next century. Cornell International Institute for Food,
Agriculture, and Development. Available at Web site: http://ciifad.cornell.edu/
documents/bellagioenglish.pdf.
Soybean 1.65 Brazil Pretty, J. and Hine, R. 2001. Op. cit.
Vegetables
Cabbage 1.21 Philippines Pretty, J. and Hine, R. 2001. Op. cit.
Vegetables 1.39 Bangladesh Pretty, J. and Hine, R. 2001. Op. cit.
Vegetables 4.15 Chile Pretty, J. and Hine, R. 2001. Op. cit.
Vegetables 2.00 Kenya Pretty, J. and Hine, R. 2001. Op. cit.
Vegetables 1.48 Malawi Pretty, J. and Hine, R. 2001. Op. cit.
Vegetables 2.00 Zimbabwe Pretty, J. and Hine, R. 2001. Op. cit.
Fruits
Fruit 1.25 Cuba Treto, E., M. Garcı
´
a, R.M. Viera, J.M. Febles. 2002. Advances in organic soil
management. In F. Funes, L. Garcı
´
a, M. Bourque, N. Pe
´
rez, and P. Rosset (eds).
Sustainable Agriculture and Resistance: Transforming Food Production in Cuba.
Food First Books, Oakland, CA. p. 164–189.
Organic agriculture and the global food supply 105
Appendix 2: Nitrogen from Cover Crops
Table A1. Continued.
Crop
Yield
ratio
Location Reference
Banana/Plantain 1.90 Uganda Pretty, J. and Hine, R. 2001. Op. cit.
Banana/Plantain 4.00 Uganda Pretty, J. and Hine, R. 2001. Op. cit.
Citrus 2.75 Pakistan Pretty, J. and Hine, R. 2001. Op. cit.
Mango 2.75 Pakistan Pretty, J. and Hine, R. 2001. Op. cit.
Milk, excl. butter
Milk 4.00 Cameroon Pretty, J. and Hine, R. 2001. Op. cit.
Milk 1.60 India Pretty, J. and Hine, R. 2001. Op. cit.
Milk 2.57 Tanzania Pretty, J. and Hine, R. 2001. Op. cit.
Milk 4.00 Tanzania Pretty, J. and Hine, R. 2001. Op. cit.
Milk 1.30 Uganda Pretty, J. and Hine, R. 2001. Op. cit.
Table A2. Data and sources for nitrogen availability from cover crops; the country where the study occurred is listed when it is known.
Multiple entries from the same source represent data for different plant species or varieties. Values with asterisk (*) were calculated based
on 66% of the N fixed by a cover crop becoming available for plant uptake during the growing season following the cover crop
34
. The
other values are the ‘fertilizer-replacement value,’ determined as the amount of N fertilizer needed to achieve yields equivalent to those
obtained using N from cover crops. Values from studies in the US were the basis for calculating the N available from cover crops for the
United States in Table 4.
kg N ha
- 1
Country Reference
Temperate (n = 33)
95.0 Canada Odhiambo, J.J.O. and Bomke, A.A. 2001. Grass legume cover crop effects on dry matter
and nitrogen ‘Crimson Clover’ accumulation. Agronomy Journal 93:299–307.
95.0 US Balkcom, K.S. and Reeves, D.W. 2005. Sunn-hemp utilized as a legume cover crop for corn
production. Agronomy Journal 97:26–31.
82.0 US Cline, G.R. and Silvernail, A.F. 2002. Effects of cover crops, nitrogen, and tillage on sweet corn.
HortTechnology 12:118–125.
94.0 US Decker, A.M., Holderbaum, J.F., Mulford, R.F., Meisinger, J.J., and Vough, L.R. 1987.
Fall-seeded legume nitrogen contributions to no-till corn production. In J.F. Power (ed.).
Role of Legumes in Conservation Tillage System: Proceedings of a national conference,
University of Georgia, Athens, April 27–29. Soil Conservation Society of America. p. 21–22.
56.0 US Drinkwater, L.E., Wagoner, P., and Sarrantonio, M. 1998. Legume-based cropping systems
have reduced carbon and nitrogen losses. Nature 396:262–265.
95.0 US Ebelhar, S.A., Frye, W.W., and Belebins, R.L. 1984. Nitrogen From legume cover crops for
no-tillage corn. Agronomy Journal 76:51–55.
104.0 US Groffman, P.M., Hendrix, P.F., and Crossley Jr, D.A. 1987. Nitrogen cycling in conventional
and no-tillage agroecosystems with inorganic fertilizer or legume nitrogen inputs. Plant
and Soil 97:325–332.
91.0 US Hargrove, W.L. 1986. Winter legumes as a nitrogen source for no-till grain sorghum. Agronomy
Journal 78:70–74.
77.0 US Herbek, J.H., Frye, W.W., and Blevins, R.L. 1987. Nitrogen from legume cover crops for
no-till corn and grain sorghum. In J.F. Power (ed.). Op. cit., p. 51–52.
99.7 US Holderbaum, J.F., Decker, A.M., Mulford, F.R., Meisinger, J.J., and Vough, L.R. 1987.
Forage contributions of winter legume cover crops in no-till corn production. In J.F. Power
(ed.). Op. cit., p. 98–99.
105.6 US Hoyt, G.D. 1987. Legumes as a green manure in conservation tillage. In J.F. Power (ed). Op.
cit., p. 96–97.
100.0 US Hoyt, G.D. and Hargrove, W.L. 1986. Legume cover crops for improving crop and soil
management in the southern United States. HortScience 21:397–492.
84.0 US Leidner, M.B. 1987. Crimson clover and corn: A conservation tillage system that works in
Georgia’s Coastal Plain. In J.F. Power (ed.). Op. cit., p. 103–104.
62.0 US Ngalla, C.F. and Eckert, D.J. 1987. Wheat-red clover interseeding as a nitrogen source for no-till
corn. In J.F. Power (ed.), Op. cit., p. 47–48.
106 C. Badgley et al.
Table A2. Continued.
kg N ha
- 1
Country Reference
79.0 US Oyer, L.J. and Touchton, J.T. 1987. Nitrogen fertilizer requirements for corn as affected by
legume cropping systems and rotations. In J.F. Power (ed.). Op. cit., p. 44–45.
84.0 US Pettygrove, G.S. and Williams, J.F. 1997. Nitrogen-fixing cover crops for California rice
production. University of California Davis Rice Project Web site.
http://agronomy.ucdavis.edu/ucce/index.htm.
60.0 US Pettygrove, G.S. and Williams, J.F. 1997. Nitrogen-fixing cover crops for California rice
production. University of California Davis Rice Project Web site.
http://agronomy.ucdavis.edu/ucce/index.htm.
40.0 US Pettygrove, G.S. and Williams, J.F. 1997. Nitrogen-fixing cover crops for California rice
production. University of California Davis Rice Project Web site.
http://agronomy.ucdavis.edu/ucce/index.htm.
77.8 US Poudel, D.D., Horwath, W.R., Lanini, W.T., Temple, S.R., and van Bruggen, A.H.C. 2002.
Comparison of soil N availability and leaching potential, crop yields and weeds in organic,
low-input and conventional farming systems in northern California. Agriculture, Ecosystems
and Environment 90:125–137.
99.7 US Poudel, D.D. et al. 2002. Op. cit.
17.8 US Reddy, K.C., Soffes, A.R., and Prine, G.M. 1986. Tropical legumes for green manure. I.
Nitrogen production and the effects on succeeding crop yields. Agronomy Journal 78:1–4.
92.4 US Reddy, K.C. et al. 1986. Op. cit.
94.6 US Reddy, K.C. et al. 1986. Op. cit.
107.8 US Reddy, K.C. et al. 1986. Op. cit.
110.0 US Reddy, K.C. et al. 1986. Op. cit.
125.4 US Reddy, K.C. et al. 1986. Op. cit.
136.4 US Reddy, K.C. et al. 1986. Op. cit.
101.6 US Sainj, U.M., Singh, B.P., and Whitehead, W.F. 1998. Cover crop root distribution and its effects
on soil nitrogen cycling. Agronomy Journal 90:511–518.
78.0 US Schmidt, W.H., Myers, D., and Van Keuren, R.W. 1974. Value of legumes for plowdown
nitrogen. Agronomy Tip Misc-4. Ohio Cooperative Extension Service, Columbus, Ohio.
231.0 US Schulz, S., Keatinge, J.D.H., and Wells, G.J. 1999. Productivity and residual effects of legumes
in rice-based cropping systems in a warm-temperate environment. II. Residual effects on rice.
Field Crops Research 61:37–49.
171.6 US Stivers, L.J., Shennan, C., Jackson, L.E., Groddy, K., Griffin, C.J., and Miller, P.R. 1993. Winter
cover cropping in vegetable production systems in California. In M.G. Paoletti, W. Foissner,
and D. Coleman (eds). Soil Biota Nutrient Cycling and Farming Systems. Lewis Publishers,
Boca Raton, FL, p. 227–240.
68.0 US Touchton, J.T., Rickerl, D.H., Walker, R.H., and Snipes, C.E. 1984. Winter legumes as nitrogen
source for no-tillage cotton. Soil and Tillage Research 4:391–401.
123.0 US Tyler, D.D., Duck, B.N., Graveel, J.G., and Bowen, J.F. 1987. Estimating response curves of
legume nitrogen contribution to no-till corn. In J.F. Power (ed.). Op. cit., p. 50–51.
95.1 Average for temperate studies (n = 33)
Tropical (n = 43)
16.5 Peoples, M.B., Herridge, D.F., and Ladha, J.K. 1995. Biological nitrogen fixation: an efficient
source of nitrogen for sustainable agricultural production? Plant and Soil 174:3–28.
52.1 Peoples, M.B. et al. 1995. Op. cit.
66.7 Peoples, M.B. et al. 1995. Op. cit.
88.1 Peoples, M.B. et al. 1995. Op. cit.
99.0 Peoples, M.B. et al. 1995. Op. cit.
101.3 Peoples, M.B. et al. 1995. Op. cit.
130.0 Peoples, M.B. et al. 1995. Op. cit.
141.2 Peoples, M.B. et al. 1995. Op. cit.
176.2 Rinaudo, G., Dreyfus, B., and Dommergues, Y. 1983. Sesbania rostrata green manure and the
nitrogen content of rice crop and soil. Soil Biology and Biochemistry 15: 111–113.
85.3 Brazil Ambrosano, E.J. et al. 2005. Utilization of nitrogen from green manure and mineral fertilizer by
sugarcane. Sci. Agric. (Piracicaba, Brazil) 62:534–542.
55.0 Colombia Cobo, J.G., Barrios, E., Kass, D.C.L., and Thomas, R.J. 2002. Decomposition and nutrient
release by green manures in a tropical hillside agroecosystem. Plant and Soil 240:331–342.
59.3 Colombia Cobo, J.G. et al. 2002. Op. cit.
60.1 Colombia Cobo, J.G. et al. 2002. Op. cit.
72.4 Colombia Cobo, J.G. et al. 2002. Op. cit.
76.4 Colombia Cobo, J.G. et al. 2002. Op. cit.
Organic agriculture and the global food supply 107
Table A2. Continued.
kg N ha
- 1
Country Reference
76.5 Colombia Cobo, J.G. et al. 2002. Op. cit.
85.7 Colombia Cobo, J.G. et al. 2002. Op. cit.
86.4 Colombia Cobo, J.G. et al. 2002. Op. cit.
95.4 Colombia Cobo, J.G. et al. 2002. Op. cit.
94.4 Cuba, Brazil Ramos, M.G., Villatoro, M.A.A., Urquiaga, S., Alves, B.J.R., and Boddey, R.M. 2001.
Quantification of the contribution of biological nitrogen fixation to tropical green manure
crops and the residual benefit to a subsequent maize crop using
15
N-isotope techniques.
Journal of Biotechnology 91:105–115.
56.1 India Becker, M., Ladha, J.K., and Ali, M. 1995. Green manure technology: potential usage and
limitations. A case study for lowland rice. Plant and Soil 174:181–194.
78.0 India Ghai, S.K., Rao, D.L.N., and Batra, L. 1988. Nitrogen contribution to wetland rice by green
manuring with Sesbania spp. in an alkaline soil. Biology and Fertility of Soils 6:22–25.
122.0 India Ghai, S.K. et al. 1988. Op. cit.
104.3 India Rao, D.L.N. and Gill, H.S. 1993. Nitrogen fixation, biomass production, and nutrient uptake by
annual Sesbania species in an alkaline soil. Biology and Fertility of Soils 15:73–78.
75.9 Nigeria Iberwiro, B., Sanginga, N., Vanlauwe, B., and Merckx, R. 2000. Evaluation of symbiotic
dinitrogen inputs of herbaceous legumes into tropical cover-crop systems. Biology and
Fertility of Soils 32:234–242.
64.4 Nigeria Mulongoy, K. 1986. Microbial biomass and maize nitrogen uptake under a Psophocarpus
palustris live-mulch grown on a tropical alfisol. Soil Biology and Biochemistry 18:395–398.
107.2 Philippines George, T., Ladha, J.K., Garrity, D.P., and Torres, R.O. 1995. Nitrogen dynamics of grain
legume-weedy fallow-flooded rice sequences in the tropics. Agronomy Journal 87:1–6.
101.3 Philippines Pareek, R.K., Ladha, J.K., and Wantanabe, I. 1990. Estimating N
2
fixation by Sesbania rostrata
and S. cannabina in lowland rice soil by the
15
N dilution method. Biology Fertility of Soils
10:77–88.
29.7 Philippines Thonnissen, C., Midmore, D.J., Ladha, J.K., Olk, D.C., and Schmidhalter, U. 2000. Legume
decomposition and nitrogen release when applied as green manures to tropical
vegetable production systems. Agronomy Journal 92:253–260.
82.5 Philippines Thonnissen, C. et al. 2000. Op. cit.
60.0 Philippines Torres, R.O., Pareek, R.P., Ladha, J.K., and Garrity, D.P. 1995. Stem-nodulating legumes as
relay-cropped or intercropped green manures for lowland rice. Field Crops Research
42:39–47.
423.0 Senegal Alazard, D. and Becker, M. 1987. Aeschynomene as green manure for rice. Plant and Soil
101:141–143.
532.0 Senegal Alazard, D. and Becker, M. 1987. Op. cit.
82.5 South Asia Ladha, J.K., Pareek, R.P., and Becker, M. 1992. Stem-nodulating legume-Rhizobium symbiosis
and its agronomic use in lowland rice. Advances in Soil Science 2:147–192.
174.2 South Asia Ladha, J.K. et al. 1992. Op. cit.
145.2 South Asia Ladha, J.K., Kundu, D.K., Coppenolle, M.G.A., Peoples, M.B., Carangal, V.R., and Dart, P.J.
1996. Legume productivity and soil nitrogen dynamics in lowland rice-based cropping
systems. Soil Science Society of America Journal 6:183–192.
139.3 South Asia Ladha, J.K. et al. 1996. Op. cit.
139.3 South Asia Ladha, J.K. et al. 1996. Op. cit.
60.7 Sri Lanka Palm, O., Weerakoon, W.L., de Silva, M.A.P., and Rosswall, T. 1988. Nitrogen mineralization
of Sesbania sesban used as green manure for lowland rice in Sri Lanka. Plant and Soil
108:201–209.
110.6 Syria Sultan, K., Ginntzburger, G., Obaton, M., Robin, C., Touchane, H., and Guckert, A. 2001.
Growth and nitrogen fixation of annual Medicago-Rhizobium associations during winter in
Mediterranean region. European Journal of Agronomy 15:221–229.
103.6 US Rotar, P.P. and Joy, R.J. 1983. ‘Tropic Sun’ sunn hemp Crotalaria juncea L. Research Series,
36. Hawaiian Institute of Tropical Agriculture and Human Resources, University of Hawaii,
Honolulu.
95.0 Uganda Wortmann, C.S., McIntyre, B.D., and Kaizzi, C.K. 2002. Annual soil improving legumes:
agronomic effectiveness, nutrient uptake, nitrogen fixation and water use. Field Crops
Research 68:75–83.
66.0 West Africa Carsky, R.J., Jagtap, S., Tian, G., Sanginga, N., and Vanlauwe, B. 1998. Maintenance of soil
organic matter and nitrogen supply in the moist savanna zone of West Africa. In R. Lal (ed).
Soil and Agricultural Sustainability. Sleeping Bear Press, Chelsea, MI.
108.6 Average for tropical studies (n = 43)
102.8 Average for all studies (n = 76)
108 C. Badgley et al.
... Negotiations also argues that despite the common misconception that the industrial farming systems of agribusiness are the most productive, many studies have shown in recent years that small farms are more productive than large farms. Badgley et. al., (2007), Pretty and Hine (2001) and Pretty et al., (2003) also posit that agroecological, sustainable and/or organic systems are as productive and, in many cases, more productive than chemical dependent monocultures because the most productive systems per unit area are highly integrated agroecological systems on small farms. Their arguments are ...
... Their arguments are relevant to this study because these organic, agroecological and sustainable ways of farming are systems used by smallholder farmers to produce food and might provide information on the spirituality of smallholder farmers through the staple food crop value chain. Badgley et al (2007), highlights research which shows that in developing countries organic farming systems on the average yield 2.7 % times more per hectare than do non organic systems. In developing countries, they yield about the same while on a global level they yield 1.3 times as much. ...
... It also has significant benefits, such as conserving soil fertility, improving system resilience to climate change, maintaining biodiversity on farmland, improving food security, and reducing greenhouse gases (Muller et al., 2016). It can modify soil's physical, chemical, and biological properties and enhance crop productivity (Badgley et al., 2007). Organic fertilizer amendment has a lower global warming potential than inorganic fertilizers (Larney & Angers, 2012). ...
... It is also evident that green manure with diversified crop rotations diminishes nitrous oxide emissions and improves soil structure (Tuck et al., 2014). Additionally, soils managed organically have significantly lower mobile nitrogen concentrations and are more aerated (Badgley et al., 2007). This study indicated that farmers more often use inorganic fertilizers to improve soil fertility than organic fertilizers. ...
Article
Full-text available
The study evaluates the farmers' choices and adoption of adaptation measures and plans by smallholder farmers to reduce the effects of climate change on their farming activities. We conducted a systematic review using the Preferred Reporting Items for Systematic Reviews and meta-Analyses (PRISMA) method. We found 66 associated studies to understand farmers' adaptation measures to climate change impacts in Africa. The paper summarizes four categories, including i) crop varieties and management; ii) water and soil management; iii) financial schemes, migration, and culture; and finally, iv) agriculture and weather services. The findings revealed that majority of studies identified crop diversification (51.5%), planting drought-tolerant varieties (45%), changing planting dates (42%), and planting early maturing crops (22%) as dominant strategies. These adaptation strategies are a welcome development and may be beneficial for responding to the impacts of climate change. However, they might not be effective during times of more extreme climate changes in the coming decades. Hence, more transformative changes, such as building more infrastructures for irrigation, promoting crop insurance , using improved varieties, and increasing opportunities for livelihood diversification, should be considered in addition to the existing adaptation strategies and potentially contributes towards SDG 1 (No Poverty) and 2 (Zero Hunger).
... Consequently, even if conventional farming provides lesser nutritious and lower protective antioxidants in food crops, it can signi cantly sustain the increased demand for food. However, amid solving the dichotomy of comparison of yield via organic farming and conventional farming, Badgley et al., (2007) came up with surprising results by stating that the system of organic farming is capable enough to produce enough food on a global per capita basis for current population or even for a larger count on a similar agricultural land base in comparison to conventional farming technique. However, the provocative statement was challenged by several prominent authors (Goulding et al., 2009;Connor, 2008, andSeufert et al., 2012) by pointing out the inaccuracies of measurement in the previous research work. ...
... Consequently, it could be stated that organic farming is the best way for enhancing soil quality and providing adequate nutrition and suppression of chemicals and pests in food crops (Badgley et al., 2007;Horrigan et al., 2002), but the conventional farming system is the most exemplary method for providing adequate global food supply by intense use of synthetic fertilizers, pesticides and chemicals (Trewavas 2001(Trewavas , 2004Conner, 2008). However, later studies (Ponisio et al., 2015& Muller et al., 2017 explored that the yield from organic farming can match the conventional farming method under speci c agricultural conditions like management practices and types of select crops. ...
Preprint
Full-text available
The study investigated the scientific output, collaboration, and impression of research on organic farming due to the increasing interest of commoners in food quality and sustainability. Efforts to enhance agroecological sustainability call for assessing the structural overview of the numerous research work done so far to understand the growth in diverse subject areas in organic farming. The scientometric method is considered for analyzing 511 documents extracted in CSV format from the Scopus online database from 2010 till July 2, 2022. The pulled-out data is analyzed via VOSviewer, revealing prominent contributing authors, cited references, the significant collaboration between the countries, total link strength, and co-occurrence of author keywords using analysis of co-authorship, co-occurrence, citation, and bibliographic coupling in several domains. Out of 511 documents published in the English language retrieved from the Scopus database, 75.29% are articles, 11.17% are review papers, and 13.52% are conference papers. In 2021, the maximum number of documents produced (n = 97) related to organic farming. India has contributed the maximum number of documents (n = 65) with the collaboration of 29 other countries and bagged 730 citations. The following study is the first to conduct a scientometric analysis in the field of food security and sustainability dimensions of organic farming, which facilitate a better understanding of the recent growth trend of research associated with organic farming on the one hand and can further improve the policies based on brainstorming to action formulation not only in academics but also in research and development on the other.
... Intensification and aggressive agricultural management have to be treated carefully because they may imply large input of nutrients, water and pesticides bringing negative consequences to the surrounding environment (like change in species composition, water pollution and eutrophication). However, intensification does not suggest necessarily industrialization of the agriculture, given that yield can also be improved in some regions, via organic farming methods, but with better practices than the ongoing ones (Badgley et al., 2007). Additional techniques of soil and water preservation can also contribute to increase yield in rain-fed regions employed for agriculture having into the account that best agricultural practices are not applied to many world agricultural areas (Godfray et al., 2010), as consequence of poor information, capacity building, access to markets, among others (Neumann, Verburg, Stehfest, & Müller, 2010). ...
Article
Full-text available
Bioenergy has emerged as a potentially sustainable alternative to the use of fossil fuels for transport and industrial uses. Developing nations, such as Colombia, can seize the advantages of modernizing rural areas by using cleaner energy and having more economic opportunities with bioenergy initiatives, provided the trade-offs between fiber, food, feed and fuel can be managed. This Thesis examines the bioenergy program now under way in Colombia, where comparative advantages (shared with other tropical countries) in production of sugar cane and palm oil are being built on. While the technologies associated with use of these feedstocks are well known, nevertheless their scaling up in a country like Colombia poses considerable environmenral, social, economic and business challenges.
... Previous literature has discussed the importance and impacts of organic farming for human society, local economy, agricultural sustainable development, and people's daily lives. Firstly, organic farming could produce enough food on a global per capita basis without increasing the burden on and pollution problems associated with local agriculture [1,2]. Secondly, organic hotspots have a positive and significant impact on local economic indicators. ...
Article
Full-text available
As the demand for organic products quickly grows in the U.S., the domestic supply of organic commodities has stagnated and failed to meet the increasing needs. To expand the organic supply capacity in the country, it is crucial to identify the key factors that could effectively promote the scale of organic farming in the U.S. Using a multivariate analytic model and state level data from multiple sources and years, this study examines a wide range of determinants that could affect organic agriculture. The results show that research funding would significantly increase organic vegetable production and the number of organic farms. The development of organic farming could be greatly encouraged by the support of research institutions. In addition, the evidence shows that abundant farm workers are essential for the organic farming sector, which is labor-intensive. Finally, a large population base could create a more stable consumer group that would promote the development of organic agriculture. These results suggest the importance of exploring and expanding consumer groups for organic commodities. These findings provide insightful implications that research support, labor availability, and a solid consumer base are crucial to boost the organic sector in the U.S. and other countries.
... the relatively slow mineralization of the composts and other organic fertilizers limits the effective nitrogen utilization (Hartz et. al., 2000). The low availability of nitrogen in organic fertilizers and insufficient quantities of organically acceptable fertilizers are the main underlying factors contributing to the low yield in organic farming (Badgley et. al., 2007). ...
... Promising advances using alternative biobased materials are available (Jiang 2017), but their ecological impacts are significant as well (Schuler et al. 2017). • In agriculture, fertilizers increase soil salinity but seem necessary to maintain productivity and feed an increasing human population (Cordell et al. 2009;Thorslund et al. 2021; but see Badgley et al. 2007 for organic approaches that could satisfy global demands). • Oil extraction and mining slurries that are high in salts are necessary by-products of homo fossil "fuelicus" (Palmer et al. 2010;Vengosh et al. 2014 Data Availability Statement: There are no data reported in this paper. ...
Article
Full-text available
Bioenergy in general, and biofuels in particular, have come up to the renewable energy stage with some peculiar strength, overall in terms of alternatives for transportation. Some of the drivers behind this option are shared on a global scale, such as the reduction of GHG’s emissions, and enhancement of energy security conditions. Some others have a more local nature, like a diversification of markets for agricultural commodities, dynamization of rural areas, improvement of micro and macro-economic indicators (for instance, income of the rural poor and national balance of payment), among others.
Conference Paper
Agricultural production is currently at a crossroads due to the need to balance the requirements of climate, biodiversity, air quality, and access to food health, farmers' incomes and economic conditions. These demands are often controversial, and the goals of policy makers are contradictory. Sustainability in agriculture needs to be put into practice. The concept of sustainable agriculture is based on agro-ecology and a system approach and aims to promote sustainable, resilient, cost-effective and stable farming systems. Based on the analysis of the scientific literature and the current situation, the paper authors have concluded that a logical path to sustainability is integrated agriculture. It is a whole farm management system that allows farmers to identify opportunities and threats and act accordingly, while also taking into account the interests of consumers in their business. The paper aims to outline the role of integrated agriculture in the development of sustainable agriculture based on the analysis of the relevant scientific literature and the current situation. Integrated management is the knowledge-based management of all available resources integrated farms are able to provide climate benefits, provide more diverse (especially pasture) land management, farm animals have a higher quality of life and survival.
Article
Full-text available
Organic farming enhances farm productivity, profitability, and soil health. The use of organic fertilizers and microbial symbiosis with species of medicinal and aromatic plants under organic agriculture helps in the improvement of yield and plant quality. However, the debate on the relative benefits of conventional and organic farming systems has, recently, gained significant interest. Thus, developing more sustainable farming practices on a large scale is of utmost importance.
Article
Full-text available
Legumes were an important component of crop rotations in the southern United States before World War II. In the post-war years, however, inexpensive and abundant fertilizer N diminished the role of N-fixing plants in cropping systems. There has been little research since 1960 on winter legumes in terms of their contribution to soil and crop management. Recent escalated costs of fertilizer N manufacture and concern over soil erosion has renewed interest in legumes and their role in cropping systems. Winter legume cover crops may provide significant quantities of fixed N while conserving soil and water resources and sustaining or improving soil productivity. This review presents both old and new information on the role of legumes in improving soil and crop management, particularly in the southern United States.