Organic agriculture in the twenty-first century

Abstract

Organic agriculture has a history of being contentious and is considered by some as an inefficient approach to food production. Yet organic foods and beverages are a rapidly growing market segment in the global food industry. Here, we examine the performance of organic farming in light of four key sustainability metrics: productivity, environmental impact, economic viability and social wellbeing. Organic farming systems produce lower yields compared with conventional agriculture. However, they are more profitable and environmentally friendly, and deliver equally or more nutritious foods that contain less (or no) pesticide residues, compared with conventional farming. Moreover, initial evidence indicates that organic agricultural systems deliver greater ecosystem services and social benefits. Although organic agriculture has an untapped role to play when it comes to the establishment of sustainable farming systems, no single approach will safely feed the planet. Rather, a blend of organic and other innovative farming systems is needed. Significant barriers exist to adopting these systems, however, and a diversity of policy instruments will be required to facilitate their development and implementation.

Full text

© 2015 Macmillan Publishers Limited. All rights reserved

Progressing organics
To be sustainable, any farm must meet four goals: productivity, environ-
mental soundness, financial viability and social responsibility. Organic agri-
culture balances multiple sustainability benefits but can it contribute more
to safely feeding the world?
See Nature Plants 1, 15221 (2016).
Image: J. Richardson
Design: S. Witham
c
2015 Macmillan Publishers Limited. All rights reserved.

NATURE PLANTS | VOL 2 | FEBRUARY 2016 | www.nature.com/natureplants 1
Organic agriculture has a history of being contentious.
Emblematic of this, and representing the prevailing attitudes
of many farmers and scientists in the 1970s and 1980s, are
the unsympathetic words uttered in 1971by then US Secretary of
Agriculture Earl Butz: “Before we go back to organic agriculture in
this country, somebody must decide which 50 million Americans
we are going to let starve or go hungry”1. At the turn of the twenty-
rst century, sceptics considered organic agriculture to be ideologi-
cally driven and inecient2,3. ey argued that organic agriculture
relies on more land to produce the same amount of food as con-
ventional agriculture and that adopting organic agriculture on too
large a scale could potentially threaten the world’s forests, wetlands
and grasslands2,3. ey also asserted that organic agriculture has too
many shortcomings and poor solutions to agricultural problems2,4.
Organic agriculture is still considered by some critics as being an
inecient approach to food security5,6 and a farming system that
will become less relevant in the future6.
Yet the number of organic farms, the extent of organically farmed
land, the amount of research funding devoted to organic farming and
the market size for organic foods have steadily increased7. Sales of
organic foods and beverages are rapidly growing, increasing almost
vefold between 1999and 2013to US$72 billion (ref.7; Fig.1); this
2013 gure is projected to double by 2018. Moreover, recent interna-
tional reports recognize organic agriculture as an innovative farm-
ing system that balances multiple sustainability goals and will be of
increasing importance in global food and ecosystem security8–10.
Here, we review the performance of organic farming systems
in the context of sustainability metrics and global challenges, and
examine some of the barriers to the adoption of organic farming
systems and the policies needed to overcome them.
Organic practices and certification
Organic agriculture, sometimes called biological or ecological
agriculture, combines traditional conservation-minded farming
methods with modern farming technologies. It emphasizes rotating
crops, managing pests naturally, diversifying crops and livestock,
and improving the soil with compost additions and animal and
green manures (Fig.2). Organic farmers use modern equipment,
improved crop varieties, soil and water conservation practices, and
Organic agriculture in the twenty-first century
John P. Reganold* and Jonathan M. Wachter
Organic agriculture has a history of being contentious and is considered by some as an inecient approach to food production.
Yet organic foods and beverages are a rapidly growing market segment in the global food industry. Here, we examine the per-
formance of organic farming in light of four key sustainability metrics: productivity, environmental impact, economic viability
and social wellbeing. Organic farming systems produce lower yields compared with conventional agriculture. However, they are
more profitable and environmentally friendly, and deliver equally or more nutritious foods that contain less (or no) pesticide
residues, compared with conventional farming. Moreover, initial evidence indicates that organic agricultural systems deliver
greater ecosystem services and social benefits. Although organic agriculture has an untapped role to play when it comes to the
establishment of sustainable farming systems, no single approach will safely feed the planet. Rather, a blend of organic and
other innovative farming systems is needed. Significant barriers exist to adopting these systems, however, and a diversity of
policy instruments will be required to facilitate their development and implementation.
the latest innovations in feeding and handling livestock. Organic
farming systems range from strict closed-cycle systems that go
beyond organic certication guidelines by limiting external inputs
as much as possible to more standard systems that simply follow
organic certication guidelines.
Rudolf Steiner’s 1924 course on biodynamic agriculture sparked
the evolution of organic agriculture in Europe1. Organic agricul-
ture was established in its own right in the 1930s and 1940s, being
developed in Britain by Lady Eve Balfour and Sir Albert Howard,
in Switzerland by Hans Mueller, in the United States by J. I. Rodale
and in Japan by Masanobu Fukuoka1. By the 1970s, organic foods
had grown in popularity, prompting the rst organic certication
standards to be draed in Europe and the United States, and com-
mencing an ongoing evolution of certiers that now includes 283
organic certication bodies worldwide operating in 170 countries7.
is proliferation of certiers reects both a complex history of
sometimes competing independent standards and the demand for
access to certiers around the world.
Many farms in both developed and less-developed countries
implement organic practices but are not certied organic. However,
growers are increasingly turning to certied organic farming sys-
tems as a way to provide verication of production methods,
decrease reliance on non-renewable resources, capture high-value
markets and premium prices, and boost farm income. Although
requirements vary slightly between certifying agencies, they pro-
mote soil quality, crop rotations, animal and plant diversity, bio-
logical processes, and animal welfare, while generally prohibiting
irradiation, sewage sludge, genetic engineering, the prophylactic
use of antibiotics, and virtually all synthetic pesticides and fertiliz-
ers. Standards continue to evolve with changing technologies and
socioecological conditions; some requirements are based on scien-
tic evidence, whereas others are driven by ideology.
As most certication standards originated in temperate devel-
oped countries, they are not always applicable in other regions, espe-
cially in less-developed countries. High demand for organic foods
in Europe and North America has resulted in the import of organic
foods from large farms in less-developed countries7. Although pre-
mium prices for exported foods may be benecial to farmers, the
inaccessibility of many of these foods to local consumers raises
Department of Crop and Soil Sciences, Washington State University, Pullman, Washington 99164, USA.
*e-mail: reganold@wsu.edu
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2 NATURE PLANTS | VOL 2 | FEBRUARY 2016 | www.nature.com/natureplants
questions about food security and social equity. Participatory guar-
antee systems, which rely on local stakeholder verication, have
emerged as a more locally focused alternative to traditional certi-
cation7, and could lead to the development of more locally relevant
visions for the production and consumption of organic foods.
Sustainability of organic agriculture
About 38% of Earth’s land cover is occupied by agriculture11.
Although agriculture provides growing supplies of food and other
products, it is a major contributor to greenhouse gases, biodiversity
loss, agrochemical pollution and soil degradation12–14. Most of these
environmental consequences come from arable land, which com-
prises around 12% of the land cover11. e challenge of feeding a
growing population expected to reach 9to 10 billion people by 2050
while protecting the environment is daunting. Adopting truly sus-
tainable farming systems on a wide scale is our best opportunity for
meeting this grand challenge and ensuring future food and ecosys-
tem security. Concerns about the unsustainability of conventional
agriculture have promoted interest in other farming systems, such
as organic, integrated and conservation agriculture8–10.
According to a US National Academy of Sciences report10, any
farm, be it organic or conventional, can only be deemed sustain-
able if it produces adequate amounts of high-quality food, enhances
the natural-resource base and environment, is nancially viable,
and contributes to the wellbeing of farmers and their communi-
ties. With the rise of organic farming in the past two decades, hun-
dreds of research studies comparing dierent aspects of organic and
conventional farming systems have been published. is section
focuses on assessing such comparison studies across these four sus-
tainability areas.
Production. Production includes crop and animal yield and their
quality. Numerous individual studies have compared yield dier-
ences between organic and conventional systems. ese data have
been synthesized in several meta-analyses or reviews; accord-
ing to these studies, yield averages are 8to 25% lower in organic
systems15–19. However, with certain crops, growing conditions and
management practices, organic systems come closer to matching
conventional systems in terms of yields. According to one such
synthesis study, the best yielding organically grown crops or crop
groups are rice, soybeans, corn and grass-clover, which yield 6 to
11% less than conventional systems; the lowest yielding are fruits
and wheat, which yield 28and 27% less, respectively17. Another
meta-analysis found fruits, soybeans and oil seed to be the highest
yielding organic crops, and wheat and vegetables the lowest, yield-
ing 37and 33% less than conventional systems respectively18. In
cases where organic crop rotations depend on green manure crops,
food production over the whole rotation may be lower than one-to-
one crop yield comparisons suggest17.
Although meta-analysis is a great tool that can describe broad
patterns not immediately visible in primary eld research19,20, it
must also be treated with caution, because no single farming sys-
tem or practice works best everywhere. Still, these studies15–19 give
strength to the argument that adoption of organic agriculture
under agroecological conditions where it performs best may close
the yield gap between organic and conventional systems. Under
severe drought conditions, which are expected to increase with
climate change in many areas, organically managed farms have
frequently been shown to produce higher yields than their conven-
tional counterparts21,22, due to the higher water-holding capacity of
organically farmed soils23. In addition, improvements in manage-
ment techniques and crop varieties for organic systems may also
close this yield gap. For example, direct selection of wheat cultivars
in organic systems has resulted in improved yields in organic sys-
tems when compared with indirect selection of wheat cultivars in
conventional systems24.
Whereas organic systems yield less food, organic foods have
signicantly less to no synthetic pesticide residues compared with
conventionally produced foods25–28. Studies have also found that
children who eat conventionally produced foods have signicantly
higher levels of organophosphate pesticide metabolites in their
urine than children who eat organically produced foods29,30. In 2012,
the American Academy of Pediatrics reported that an organic diet
reduces children’s exposure to pesticides, and provided resources
for parents seeking guidance on which foods tend to have the high-
est pesticide residues31. Although these data show that organic foods
Sales of organic food (US$billion)
Organic land area (ha × 10
6
)
Sales, Europe
Sales, other
Sales, North America
Global sales, no breakdown
Organic land area
80
70
60
50
40
30
20
10
0
45
40
35
30
25
20
15
10
5
0
1997
1998
2000
1999
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
Year
Figure 1 | Annual global market for organic foods and land area of organic
production. Increasing sales of organic food in nominal billions of US
dollars (bars), broken down by contributions from North America (red),
Europe (green) and the rest of the world (orange), and increasing total
global land area under organic production in millions of hectares (blue
line)7,96–98. European and North American contributions were not available
for the years 1998 through 2000, shown in grey.
Biologically
active soil
Diverse
crop and
livestock
rotation
Balanced
nutrient
supply
Disease
management
Physical methods
Species, variety
and breed
selection
Supplementary
lime, organic
fertilizers and
compost
Hedges,
margins
and other
habitat areas
Biological
controls
Food, fibre and fuel for
human and livestock use
and consumption
Crop and
animal
health Weed
management
Biological
controls
Pest
management
Temporal and
spatial patterns
Diverse
species
balance
Figure 2 | Organic management practices. The complex interactions
among structural factors and tactical management strategies on a
diversified organic farm producing food, fibre and fuel for human and
livestock use and consumption. Structural factors, represented by
circles, are the foundation of organic management, with diverse crop and
livestock rotations at the centre. Tactical management decisions are used
to supplement the structural factors and include the use of: biological
controls; supplementary lime, organic fertilizers and compost; hedges,
margins and other habitat areas; species, variety and breed selection;
temporal and spatial patterns; and physical weed management. Figure
adapted from ref.99, © 2001 Elsevier.
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NATURE PLANTS | VOL 2 | FEBRUARY 2016 | www.nature.com/natureplants 3
may present some clear advantages when it comes to synthetic pes-
ticide residues, the human health impacts of pesticide exposure
from food are not clear26, and organically certied pesticides need
to be better identied and taken into account28.
At least 15 reviews or meta-analyses26,27,32–44 of the scientic
literature comparing the nutrition of organic and conventional
foods have been published in the past 15years. Twelve of these
studies27,32–34,36–39,41–44 found some evidence of organic food being
more nutritious (for instance, having higher concentrations of
vitaminC, total antioxidants and total omega-3 fatty acids, and
higher omega-3to -6 ratios). Whether or not these are nutritionally
meaningful dierences continues to be debated26,43. e other three
studies26,35,40 concluded that there were no consistent nutritional dif-
ferences between organic and conventional foods. However, one of
the three studies found that conventional chicken and pork had a
33% higher risk for contamination with antibiotic-resistant bacteria
compared with organic alternatives26.
Environment. Reviews and meta-analyses generally support the
perception that organic farming systems are more environmentally
friendly than conventional farming systems45–58. For example, such
aggregate studies have found that organic farming systems con-
sistently have greater soil carbon levels, better soil quality and less
soil erosion compared with conventional systems45–51. In addition,
organic farms generally have more plant diversity, greater faunal
diversity (insects, soil fauna and microbes, birds) and oen more
habitat and landscape diversity46–55. Most functional groups, such as
herbivores, pollinators, predators and producers (plants), are more
diverse in organic farming systems51–53. Moreover, in a study cov-
ering eight western and eastern European countries, insecticides
and fungicides had consistently negative eects on biodiversity,
with insecticides also reducing the biological control potential in
farming systems56.
As organic agriculture uses virtually no synthetic pesticides,
there is little to no risk of synthetic pesticide pollution of ground
and surface waters46. With respect to nitrate and phosphorous leach-
ing and greenhouse gas emissions, organic farming systems score
better than conventional farming when expressed per unit produc-
tion area46,49,51,57,58; however, given the lower land-use eciency of
organic farming in developed countries, this positive eect is less
pronounced and in some cases reversed when expressed per unit
product49,57,58. In a meta-analysis of environmental quality param-
eters, organic farms were found to have lower nitrate leaching,
nitrous oxide emissions and ammonia emissions per unit of eld
area, but higher leaching and emissions per unit product48. Severe
degradation of freshwater and marine ecosystems around the world
is linked to excessive use of nitrogen and phosphorous fertiliz-
ers12,59, leading to eutrophication of freshwater and the production
of hypoxic zones in coastal waters. Lower nutrient pollution from
organic compared with conventional systems can be illustrated by
dierences in their nitrogen cycling and losses (Fig.3).
Organic systems are usually more energy ecient than their
conventional counterparts46–48,51,54,58. For example, in Germany, Italy,
Sweden and Switzerland, organic farms were found to use signi-
cantly less energy on a per-hectare basis than their conventional
counterparts, and 70% of organic farms and 30% of conventional
farms had signicantly lower energy consumption per unit of out-
put45. e generally lower energy use46–48,54 and higher soil organic
matter45–49 of organic systems make them ideal blueprints for devel-
oping methods to limit fossil fuel emissions and build soil carbon
stores, important tools in addressing climate change.
Economics. Whether organic agriculture can continue to expand
globally will primarily be determined by its nancial performance
compared with conventional agriculture17,60. e main factors that
determine the protability of organic agriculture include crop yields,
labour and total costs, price premiums for organic products, the
potential for reduced income during the organic transition period
(usually three years), and potential cost savings from the reduced
reliance on non-renewable resources and purchased inputs61.
To the best of our knowledge, only one meta-analysis has ana-
lysed the nancial performance of organic and conventional agri-
culture20. e analysis combines ndings from 40years of studies
covering 55 crops grown on ve continents. When actual price
premiums (higher prices awarded to organic foods) were included,
organic agriculture proved signicantly more protable (22to 35%
greater net present values) and had higher benet/cost ratios (20to
24%) than conventional agriculture. When organic premiums
were taken away, net present values (−27to −23%) — net returns
accounting for the time value of money — and benet/cost ratios
(−8to −7%) of organic agriculture were signicantly lower than
conventional agriculture20.
Mineralization
N export
in harvest
N export
in harvest
Crop N
uptake
Erosion N loss
Immobilization
Atmospheric
N deposition
Atmospheric
N deposition
Volatile N loss
during senescence
Volatile N loss
during senescence
N leaching
Crop residue N return
N loss through
denitrification
N loss through
denitrification
Fertilizer N
addition
Fertilizer N
addition
Biological
N fixation
Biological
N fixation
a
Mineralization
Crop N
uptake
Erosion N loss
Immobilization
N leaching
Crop residue N return
N runoN runo
b
N added in
manure and
amendments
N added in
manure and
amendments
Gaseous
N loss
Gaseous
N loss
N fixed
by lightning
N fixed
by lightning
Soil
organic N Crop N
Soil
mineral N Crop N
Soil
organic N
Soil
mineral N
Figure 3 | Hypothetical nitrogen stocks and flows of two contrasting cropping systems. a,b, Cropping systems relying mainly on mineral nitrogen inputs
(a) have relatively higher nitrogen losses to air and water than cropping systems with emphasis on biological N fixation, manure and other organic matter
amendments, cover crops and perennial crops, and low reliance on mineral N fertilizer, such as organic and integrated systems (b). The width of the
arrows is relative to the size of the nitrogen flux; boxes representing nitrogen stocks are not scaled to the pool size. Figure adapted from ref.100, © 2015
The National Academies100. Arrows represent nitrogen inputs (green), losses (orange) and transformations (blue).
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Although price premiums were 29to 32%, breakeven premi-
ums necessary for organic prots to match conventional prots
were only 5to 7%, even with organic yields being 10to 18% lower.
e size of organic premiums awarded, and the dierence between
organic premiums and breakeven premiums, were consistent dur-
ing the 40-year study period. e fact that organic premiums were
signicantly higher than breakeven premiums suggests that organic
agriculture can continue to expand even if premiums decline. e
study also found that total costs were not signicantly dierent, but
labour costs were signicantly (7to 13%) higher with organic farm-
ing practices20. Although one of the successes of conventional agri-
culture has been its ability to produce more with less labour, some
have found the extra labour of organic agriculture to be benecial
in providing rural employment and development opportunities62,63.
Few economic studies have accounted for negative externalities
(such as environmental costs) or positive externalities (such as eco-
system services), with associated monetary values, in organic and
conventional comparison studies. Putting a price on the negative
externalities caused by farming, such as soil erosion or nitrate leach-
ing into groundwater, would make organic agriculture even more
protable, given that its environmental impact is less than that of
conventional agriculture45–58. Indeed, it has been estimated that a
switch to organic production would lower the external costs of agri-
cultural production in the United Kingdom by 75%, from £1,514
million yr–1 to £385 million yr–1 (ref.64).
A number of studies (for example, refs65,66) have compared
ecosystem services in organic and conventional farming systems.
A few of these studies have accounted for the monetary value of
ecosystem services; these studies generally show that conventional
practices decrease the ability of farms to provide some economically
signicant ecosystem services relative to organic practices67–69. For
example, in a study comparing 14 organic arable elds with 15 con-
ventional ones in New Zealand70, the total economic value of three
ecosystem services (biological pest control, soil formation and the
mineralization of plant nutrients) in the organic elds was signi-
cantly greater at US$232ha−1yr−1 compared with the conventional
elds at US$146ha−1yr−1. Factoring in such dierences in economic
comparison studies would probably make up for price premiums
awarded to organic products. Price premiums and European sub-
sidies for organic farms are oen justied on the grounds that they
compensate farmers for providing ecosystem services or avoiding
damage to the environment.
Wellbeing. How well organic, conventional and other farming
systems are performing in areas such as social equity (for instance,
issues of gender, race, ethnicity and class) and quality of life for farm
families and communities remains unclear due to limited research.
Available data indicate that both organic and conventional farming
systems need to make signicant progress to meet social sustain-
ability goals10. However, organic farming has been shown to have
some sociocultural strengths, such as positive shis in community
economic development, increased social interactions between farm-
ers and consumers71,72, and greater employment of farm workers and
cooperation among farmers62,63.
Although organic farming oen requires additional manual
work on the farm, it reduces the exposure of farm workers to pesti-
cides and other chemicals. Such exposure can be particularly prob-
lematic in less-developed countries, where illnesses and death have
resulted from occupational and accidental exposure (due in part
to the fact that it is impractical and expensive for workers to use
safety equipment)73,74.
Organic certication programmes have adopted social wellbe-
ing goals. Guidelines of the International Federation of Organic
Agriculture Movements (IFOAM) stipulate that organic farmers
should be able to support themselves and other workers with fair
incomes, while maintaining safe and dignied working conditions75.
Furthermore, organically certied animals must be raised humanely
under conditions that allow for the expression of their natural behav-
iours and needs75. For example, European Union, US and Japanese
rules on organic production require livestock to have access to open
air or grazing whenever possible, and that sick animals be treated as
needed, even with the use of antibiotics if required76–78.
Organic farming can improve food security by diversifying
on-farm crop and livestock operations, which diversies income
sources and improves variety in diets79. Organic farming necessi-
tates diverse crop and livestock rotations, encourages the integration
Conventional
Biodiversity
Profitability
Total costs
Ecosystem
services
Employment
of workers
Minimize
pesticide
residues
Nutritional
quality
Yield
Minimize
energy
use
Minimize
water
pollution
Organic
Reduce
worker
exposure to
pesticides
Soil quality
Biodiversity
Profitability
Total costs
Ecosystem
services
Employment
of workers
Minimize
pesticide
residues
Nutritional
quality
Yield
Minimize
energy
use
Minimize
water
pollution
Reduce
worker
exposure to
pesticides
Soil quality
Figure 4 | Assessment of organic farming relative to conventional farming in the four major areas of sustainability. Lengths of the 12 flower petals
are qualitatively based on the studies discussed in this Review15–23,25–29,32–56,58,62–74 and indicate the level of performance of specific sustainability metrics
relative to the four circles representing 25, 50, 75 and 100%. Orange petals represent areas of production; blue petals represent areas of environmental
sustainability; red petals represent areas of economic sustainability; green petals represent areas of wellbeing. The lengths of the petals illustrate that
organic farming systems better balance the four areas of sustainability.
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NATURE PLANTS | VOL 2 | FEBRUARY 2016 | www.nature.com/natureplants 5
of multiple farm enterprises and encourages the use of leguminous
crops for biological nitrogen xation. By growing a higher diversity
of more nutrient-rich (such as vegetables) and more protein-rich
(such as legumes and meats) foods, whether for export or subsist-
ence, a farmer has access to at least a portion of these foods. For
example, following 840 small organic and non-organic farms in the
Philippines, researchers found the increase in vegetable and protein
consumption from 2000to 2007to be two to three times greater for
the more diversied organic farmers than conventional farmers80.
Balancing sustainability metrics. Some argue that signicantly
scaling-up organic land area may increase nitrogen and other nutri-
ent limitations on yields17, and question whether the greater land
area required by organic agriculture to maintain yields counteracts
its environmental gains2,3. Probably the biggest criticism of organic
agriculture is its lower yields compared with conventional agricul-
ture4,5, a particularly salient challenge given the task of feeding a
growing world population without further agricultural expansion13.
Conversely, some contend that the environmental advantages of
organic agriculture far outweigh the lower yields, and that increasing
research and breeding resources for organic systems would reduce
the yield gap16,17,24,81. Others suggest that multifunctional farming
systems, such as organic, coupled with more plant-based diets and
reduced food waste, are necessary elements of a more sustainable
food system16,54,65. Sometimes excluded from these arguments is the
fact that we already produce adequate kilocalories of food to more
than feed the world but do not provide adequate access to all indi-
viduals82. Globally, 1.9 billion adults are overweight and of these 600
million are obese83, while 793 million people are undernourished
and more than 28% of children under the age of veare stunted due
to malnourishment82,84.
Debates aside, although yield is an important sustainability
metric, the issue is more complicated than kilograms of food per
hectare. Mainstream conventional farming systems have provided
growing supplies of food and other products but oen at the expense
of the other three sustainability goals. Environmental degradation,
public health problems, loss of crop variety and genetic biodiversity,
and severe impacts on ecosystem services have not only accompa-
nied conventional farming systems but have oen extended well
beyond their eld boundaries. Such negative externalities are not
accounted for.
e performance of organic farming systems in the context of
sustainability metrics indicates that they better balance multiple
sustainability goals than their conventional counterparts (Fig.4).
Based on present evidence, we argue that although organic farm-
ing systems produce lower yields compared with conventional agri-
culture, they are more protable and environmentally friendly, and
deliver equal or more nutritious foods with less to no pesticide resi-
dues. In addition, initial evidence indicates that organic agriculture
is better at enhancing the delivery of ecosystem services, other than
yield, as well as some social sustainability benets. Importantly, the
body of research studies has been heavily biased towards developed
countries, whereas studies in the less-developed world, especially in
tropical and subtropical climates, need to be greatly increased.
With only 1% of global agricultural land in organic production7,
and with its multiple sustainability benets, organic agriculture can
contribute a larger share in feeding the world. Yet, signicant barri-
ers to farmers adopting organic practices remain in both developed
and less-developed countries.
Barriers and policies
Obstacles to farmers adopting organic agriculture include power-
ful vested interests and existing policies, a lack of information and
knowledge, weak infrastructure and other economic challenges,
and misperceptions and cultural biases (Fig.5). Global and national
agribusiness corporations, agrochemical industries, commodity
groups and food companies have a strong vested interest in the
conventional agroindustrial model, command ever-greater market
power in the food system and have heavily inuenced public policy
to favour this model10,85. e consolidation of industries, the con-
centration of market power, and many past and current agricultural
policies have led to decreased agricultural diversity10 and have dis-
incentivized agricultural innovation81.
Considerably less public and private funding has been put
towards research and development for organic systems than towards
conventional systems worldwide; this has resulted in a lack of crop
and livestock breeding for organic farming conditions and a dearth
of knowledge and information resources supporting organic farm-
ers17,19. Historically, public funding for research on organic systems
has been higher in Europe than in the United States7. Moreover,
research on organic agriculture in less-developed countries rep-
resents only a small fraction of the overall scientic literature on
the topic17,19,52.
Some farmers face infrastructure and economic barriers, which
include certication costs and access to markets, loans and insur-
ance. Many areas, especially rural regions and less-developed coun-
tries, lack access to additional labour, markets for organic foods,
infrastructure for storage and distribution, or appropriate certi-
cation requirements86,87. Finally, strong cultural biases against the
connotations of organic agriculture, and conventional mindsets
held by some individuals and organizations, limit the spread of
organic practices86,87.
With these obstacles in mind, governments should focus on
creating an enabling environment for the development and adop-
tion of not just organic but also other innovative and more sustain-
able farming systems88. ese eorts must be targeted at improving
agricultural performance in all four areas of sustainability and
will require a diversity of knowledge-based, legal and nancial
policy instruments89.
Knowledge-based policy instruments are needed to create an
enabling environment for agricultural innovation, education and
outreach. Specically, policy instruments must: ensure farmer
and scientist engagement in research and development decision-
making; improve farmer knowledge and capacity through eective
extension and outreach infrastructure, such as the use of farmer
eld schools and communication technologies; and enhance wom-
en’s educational and leadership opportunities90.
Legal instruments must play a stronger role in ensuring open and
competitive markets, limiting commercial inuence in government
and increasing transparency in the food production system. In addi-
tion, they are needed to reduce food waste, to improve the security
of land tenure for farmers, and to develop national targets for trade
policies that promote food and ecosystem security.
Financial instruments are needed to give monetary value to the
externalities that arise from agricultural practices and to empower
farmers through access to capital, infrastructure and competitive
markets88. In developed countries, direct and indirect crop subsidies
and biofuel incentives should be replaced by targeted agro-environ-
mental incentives, such as payments for biodiversity protection
and soil conservation. Some policy organizations have found that
raising the costs of fossil fuels, irrigation water and other limited
resources strongly encourages more ecient farming systems91. In
less-developed countries, targeted input subsidies and investment in
rural infrastructure are key nancial instruments. For example, sub-
sidizing organic nutrient inputs alongside mineral fertilizer inputs
for the poorest farmers can be an eective strategy for increasing
yields and building soils92.
Beyond organic
More than 40years aer Earl Butz’s comment, we are in a new era
of agriculture, as reected in the words of current US Secretary
of Agriculture Tom Vilsack: “Organic agriculture is one of the
REVIEW ARTICLE
NATURE PLANTS DOI: 10.1038/NPLANTS.2015.221
© 2016 Macmillan Publishers Limited. All rights reserved

6 NATURE PLANTS | VOL 2 | FEBRUARY 2016 | www.nature.com/natureplants
fastest growing segments of American agriculture and helps farmers
receive a higher price for their product as they strive to meet grow-
ing consumer demand”93. Moreover, organic agriculture has been
able to provide jobs, be protable, benet the soil and environment,
and support social interactions between farmers and consumers.
Although organic agriculture has an untapped potential role in
global food and ecosystem security, no one farming system alone
will safely feed the planet. Rather, a blend of organic and other inno-
vative farming systems, including agroforestry, integrated farming,
conservation agriculture, mixed crop and livestock, and still undis-
covered systems, will be needed for future global food and ecosys-
tem security. For example, integrated farming systems that blend
mostly organic with some conventional practices have been shown
to be more sustainable than conventional farming systems94,95 and
are likely to play a central role. Achieving global food and ecosys-
tem security requires more than just achieving sustainable farming
systems worldwide. We need to reduce food waste, improve food
distribution and access, stabilize the human population, eliminate
the conversion of food into fuel, and change consumption patterns
towards a more plant-based diet.
Equal adherence to all four sustainability goals of production,
environment, economics and social wellbeing does not limit but
encourages farmers and researchers to innovate. e challenge fac-
ing policymakers is to create an enabling environment for scaling-up
organic and other innovative farming systems to move towards truly
sustainable production systems. is is no small task, but the con-
sequences for food and ecosystem security could not be bigger. To
make this happen will require mobilizing the full arsenal of eective
policies, scientic and socioeconomic advances, farmer ingenuity
and public engagement.
Received 7 September 2015; accepted 17 December 2015;
published online 3 February 2016
References
1. Lockeretz, W. in Organic Farming: An International History (ed. Lockeretz, W.)
1–8 (CABI, 2007).
2. Trewavas, A. Urban myths of organic farming. Nature 410, 409–410 (2001).
3. Emsley, J. Going one better than nature? Nature 410, 633–634 (2001).
4. Kirchmann, H. & orvaldsson, G. Challenging targets for future agriculture.
Eur. J.Agron. 12, 145–161 (2000).
5. Connor, D.J. & Mínguez, M.I. Evolution not revolution of farming systems
will best feed and green the world. Glob. Food Secur. 1, 106–113 (2012).
6. Pickett, J.A. Food security: intensication of agriculture is essential, for which
current tools must be defended and new sustainable technologies invented.
Food Energ. Secur. 2, 167–173 (2013).
7. Willer, H. & Lernoud, J. (eds) e World of Organic Agriculture: Statistics and
Emerging Trends 2015 (FiBL-IFOAM, 2015).
8. International Assessment of Agricultural Science and Technology for
Development Agriculture at a Crossroads: Global Report (Island, 2009).
•
Increased farmer access to capital
•
Elimination of crop subsidies and
biofuel incentives
•
Use of agro-environmental incentives
•
Increased costs of scarce resources
•
Targeted input subsidies for
resource-poor farmers
•
Investment in rural infrastructure
• Public investment in agroecological research
• Farmer engagement in research and development
• Outreach to improve farmer knowledge and capacity
• Enhancement of women's educational and leadership opportunities
• Increased transparency throughout the food chain
Financial instruments
Knowledge-based instruments
Legal instruments
• Measures to ensure open and
competitive markets
• Reduction of commercial influence
in government
•
Development of national targets and trade
policies for food and ecosystem security
• Enhanced security of land tenure
B
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Economics
Wellbeing
Sustainable
agriculture
EnvironmentProduction
Figure 5 | Policy instruments for overcoming barriers to farmers adopting more sustainable farming systems. For any farm to be sustainable, it must
meet four goals, shown in the centre: (1) produce adequate amounts of high-quality food (production); (2) enhance the natural-resource base and
environment (environment); (3) be financially viable (economics); and (4) contribute to the wellbeing of farmers and their communities (wellbeing)10.
Despite the appeal of a sustainable agriculture philosophy, the task for farmers to achieve agricultural sustainability is challenging. Just because a farm
is organic does not mean that it is sustainable. However, research shows that organic farming systems better balance the four sustainability goals than
their conventional counterparts and are more likely to achieve agricultural sustainability (overlapping area). Yet, significant barriers to adopting organic
agriculture exist, including powerful vested interests and existing policies, lack of information and knowledge, weak infrastructure and other economic
challenges, and misperceptions and cultural biases. In fact, many of these same barriers exist for other innovative systems, such as agroforestry,
conservation agriculture, integrated farming and mixed crop–livestock systems. A diversity of policy instruments is needed to overcome these barriers, and
can be categorized as financial, legal and knowledge-based instruments. Examples of these instruments are shown in the figure.
REVIEW ARTICLE NATURE PLANTS DOI: 10.1038/NPLANTS.2015.221
© 2016 Macmillan Publishers Limited. All rights reserved

NATURE PLANTS | VOL 2 | FEBRUARY 2016 | www.nature.com/natureplants 7
9. De Schutter, O. Report Submitted by the Special Rapporteur on the Right to
Food (United Nations, 2010).
10. National Research Council Toward Sustainable Agricultural Systems in the 21st
Century (e National Academies, 2010).
11. Food and Agriculture Organization of the United Nations FAOSTAT Online
Database (accessed August 2015); http://faostat.fao.org/site/377/default.
aspx#ancor
12. Rockström, J. etal. A safe operating space for humanity. Nature
461, 472–475 (2009).
13. Godfray, H.C. J. etal. Food security: the challenge of feeding 9 billion people.
Science 327, 812–818 (2010).
14. Amundson, R. etal. Soil and human security in the 21st century. Science
348, 1261071 (2015).
15. Stanhill, G. e comparative productivity of organic agriculture. Agr. Ecosyst.
Environ. 30, 1–26 (1990).
16. Badgley, C. etal. Organic agriculture and the global food supply. Renew. Agr.
Food Syst. 22, 86–108 (2007).
17. de Ponti, T., Rijk, B. & van Ittersum, M.K. e crop yield gap between organic
and conventional agriculture. Agr. Syst. 108, 1–9 (2012).
18. Seufert, V., Ramankutty, N. & Foley, J.A. Comparing the yields of organic and
conventional agriculture. Nature 485, 229–232 (2012).
19. Ponisio, L.C. etal. Diversication practices reduce organic to conventional
yield gap. Proc. R.Soc. B 282, 20141396 (2015).
20. Crowder, D.W. & Reganold, J.P. Financial competitiveness of
organic agriculture on a global scale. Proc. Natl Acad. Sci. USA
112, 7611–7616 (2015).
21. Lockeretz, W., Shearer, G. & Kohl, D.H. Organic farming in the Corn Belt.
Science 211, 540–547 (1981).
22. Lotter, D., Seidel, R. & Liebhardt, W. e performance of organic and
conventional cropping systems in an extreme climate year. Am. J.Alternative
Agr. 18, 146–154 (2003).
23. Siegrist, S., Scaub, D., Pner, L. & Mäder, L. Does organic agriculture reduce
soil erodability? e results of a long-term eld study on loess in Switzerland.
Agr. Ecosyst. Environ. 69, 253–264 (1998).
24. Murphy, K.M., Campbell, K.G., Lyon, S.R. & Jones, S.S. Evidence
of varietal adaptation to organic farming systems. Field Crop. Res.
102, 172–177 (2007).
25. Baker, B.P., B e n b r o o k , C . M., Groth, E. III & Benbrook, K.L. Pesticide residues
in conventional, integrated pest management (IPM)-grown and organic foods:
insights from three US data sets. Food Ad dit. Co ntam. 19, 427–446 (2002).
26. Smith-Spangler, C. etal. Are organic foods safer or healthier than
conventional alternatives? Ann. Intern. Med. 157, 348–366 (2012).
27. Barański, M. etal. Higher antioxidant and lower cadmium concentrations and
lower incidence of pesticide residues in organically grown crops: a systematic
literature review and meta-analyses. Brit. J.Nutr. 112, 794–811 (2014).
28. Pussemier, L., Larondelle, Y., Van Peteghem, C. & Huyghebaert, A. Chemical
safety of conventionally and organically produced foodstus: a tentative
comparison under Belgian conditions. Food Control 17, 14–21 (2006).
29. Curl, C.L., Fenske, R.A. & Elgethun, K. Organophosphorus pesticide
exposure of urban and suburban preschool children with organic and
conventional diets. Environ. Health Persp. 111, 377–382 (2003).
30. Lu, C. etal. Organic diets signicantly lower children’s dietary exposure to
organophosphorus pesticides. Environ. Health Persp. 114, 260–263 (2006).
31. Forman, J. etal. Organic foods: health and environmental advantages and
disadvantages. Pediatrics 130, e1406–e1415 (2012).
32. Soil Association Organic Farming, Food Quality and Human Health: A Review
of the Evidence (Soil Association, 2000); http://soilassociation.org/LinkClick.as
px?leticket=cY8kfP3Q%2BgA%3D
33. Brandt, K. & Mølgaard, J.P. Organic agriculture: does it enhance or reduce the
nutritional value of plant foods? J.Sci. Food Agr. 81, 924–931 (2001).
34. Worthington, V. Nutritional quality of organic versus conventional fruits,
vegetables, and grains. J.Alter. Complem. Med. 7, 161–173 (2001).
35. Bourn, D. & Prescott, J. A comparison of the nutritional value, sensory
qualities, and food safety of organically and conventionally produced foods.
Critical Rev. Food Sci. 42, 1–34 (2002).
36. Williams, C.M. Nutritional quality of organic food: shades of grey or shades
of green? Proc.Nutr. Soc. 61, 19–24 (2002).
37. Magkos, F., Arvaniti, F. & Zampelas, A. Organic food: nutritious food
or food for thought? A review of the evidence. Int. J.Food Sci. Nutr.
54, 357–371 (2003).
38. Rembialkowska, E. Quality of plant products from organic agriculture. J.Sci.
Food Agr. 87, 2757–2762 (2007).
39. Benbrook, C., Zhao, X., Yáñez, J., Davies, N. & Andrews, P. New Evidence
Conrms the Nutritional Superiority of Plant-based Organic Foods (e
Organic Center, 2008); http://organic-center.org
40. Dangour, A.D. etal. Nutritional quality of organic foods: a systematic review.
Am. J.Clin. Nutr. 90, 680–685 (2009).
41. Hunter, D. etal. Evaluation of the micronutrient composition of plant foods
produced by organic and conventional agricultural methods. Crit. Rev. Food
Sci. 51, 571–582 (2011).
42. Lairon, D. Nutritional quality and safety of organic food: a review. Agron.
Sustain. Dev. 30, 33–41 (2010).
43. Brandt, K., Leifert, C., Sanderson, R. & Seal, C.J. Agroecosystem management
and nutritional quality of plant foods: the case of organic fruits and vegetables.
Crit. Rev. Plant Sci. 30, 177–197 (2011).
44. Palupi, E., Jayanegara, A., Ploeger, A. & Kahl, J. Comparison of nutritional
quality between conventional and organic dairy products: a meta-analysis.
J.Sci. Food. Agr. 92, 2774–2781 (2012).
45. Gattinger, A. etal. Enhanced top soil carbon stocks under organic farming.
Proc. Natl Acad. Sci. USA 109, 18226–18231 (2012).
46. Alföldi, T. etal. in Organic Agriculture, Environment, and Food
Security (eds Scialabba, N.E.-H. & Hattam, C.) Ch. 2 (FAO, 2002);
www.fao.org/docrep/005/y4137e/y4137e00.htm
47. Kaspercyk, N. & Knickel, K. in Organic Agriculture: A Global Perspective
(eds Kristiansen, P., Taji, A. & Reganold, J.) 259–294 (CSIRO, 2006).
48. Tuomisto, H.L., Hodge, I.D., Riordan, P. & Macdonald, D.W. Does organic
farming reduce environmental impacts? A meta-analysis of European
research. J.Environ. Manage. 112, 309–320 (2012).
49. Mondelaers, K., Aertsens, J. & Van Huylenbroeck, G. A meta-analysis of the
dierences in environmental impacts between organic and conventional
farming. Brit. Food. J. 111, 1098–1119 (2009).
50. Gomiero, T., Pimentel, D. & Paoletti, M.G. Environmental impact of dierent
agricultural management practices: conventional vs. organic agriculture.
Crit. Rev. Plant Sci. 30, 95–124 (2011).
51. Lynch, D.H., Halberg, N. & Bhatta, G.D. Environmental impacts of organic
agriculture in temperate regions. CAB Rev. 7, 1–17 (2012).
52. Tuck, S. etal. Land-use intensity and the eects of organic farming on
biodiversity: a hierarchical meta-analysis. J.Appl. Ecol. 51, 746–755 (2014).
53. Kennedy C. M. et al. A global quantitative synthesis of local and
landscape eects on wild bee pollinators in agroecosystems. Ecol. Lett.
16, 584–599 (2013).
54. Lotter, D.W. Organic agriculture. J.Sustain. Agr. 21, 59–128 (2003).
55. Crowder, D.W., Northeld, T.D., Strand, M.R. & Snyder, W.E.
Organic agriculture promotes evenness and natural pest control. Nature
466, 109–112 (2010).
56. Geiger, F. etal. Persistent negative eects of pesticides on biodiversity
and biological control potential on European farmland. Basic Appl. Ecol.
11, 97–105 (2010).
57. Skinner, S. etal. Greenhouse gas uxes from agricultural soils under organic
and non-organic management — a global meta-analysis. Sci. Total Environ.
468–469, 553–563 (2014).
58. Lee, K.S., Choe, Y.C. & Park, S.H. Measuring the environmental eects of
organic farming: a meta-analysis of structural variables in empirical research.
J.Environ. Manage. 162, 263–274 (2015).
59. Steen, W. etal. Planetary boundaries: guiding human development on a
changing planet. Science 347, 1259855 (2015).
60. Halberg, N., Sulser, T.B., Høgh-Jensen, H., Rosegrant, M.W. & Knudsen,
M.T. in Global Development of Organic Agriculture: Challenges and Prospects
(eds Halberg, N. et al.) 277–322 (CABI, 2006).
61. Zentner, R.P. etal. Eects of input management and crop diversity on
economic returns and riskiness of cropping systems in the semi-arid Canadian
Prairie. Renew. Agr. Food Syst. 26, 208–223 (2011).
62. Prihtanti, T.M., Hardyastuti, S., Hartono, S. & Irham Social-cultural functions
of rice farming systems. Asian J.Agr. Rural Dev. 4, 341–351 (2014).
63. Mendoza, T.C. Evaluating the benets of organic farming in rice
agroecosystems in the Philippines. J.Sustain. Agr. 24, 93–115 (2004).
64. Pretty, J.N., Ball, A.S., Lang, T. & Morison, J.I. L. Farm costs and food miles:
an assessment of the full cost of the UK weekly food basket. Food Policy
30, 1–19 (2005).
65. Kremen, C. & Miles, A. Ecosystem services in biologically diversied versus
conventional farming systems: benets, externalities, and trade-os. Ecol. Soc.
17, 40 (2012).
66. Andersson, G.K. S., Rundlöf, M. & Smith, H.G. Organic farming improves
pollination success in strawberries. PLoS One 7, e31599 (2012).
67. Porter, J., Costanza, R., Sandhu, H., Sigsgaard, L. & Wratten, S. e value of
producing food, energy, and ecosystem services within an agro-ecosystem.
Ambio 38, 186–193 (2009).
68. Sandhu, H. etal. Signicance and value of non-traded ecosystem services on
farmland. PeerJ 3, e762 (2015).
69. Östman, Ö., Ekbom, B. & Bengtsson, J. Yield increase attributable to aphid
predation by ground-living polyphagous natural enemies in spring barley in
Sweden. Ecol. Econ. 45, 149–158 (2003).
70. Sandhu, H.S., Wratten, S.D. & Cullen, R. e role of supporting ecosystem
services in conventional and organic arable farmland. Ecol. Complex.
7, 302–310 (2010).
REVIEW ARTICLE
NATURE PLANTS DOI: 10.1038/NPLANTS.2015.221
© 2016 Macmillan Publishers Limited. All rights reserved

8 NATURE PLANTS | VOL 2 | FEBRUARY 2016 | www.nature.com/natureplants
71. MacRae, R.J., Frick, B. & Martin, R.C. Economic and social impacts of
organic production systems. Can. J.Plant Sci. 87, 1037–1044 (2007).
72. Gruère, G., Nagarajan, L. & King, E.D. I.O. e role of collective action in the
marketing of underutilized plant species: lessons from a case study on minor
millets in South India. Food Policy 34, 39–45 (2009).
73. Eddleston, M. etal. Pesticide poisoning in the developing world — a
minimum pesticides list. Lancet 360, 1163–1167 (2002).
74. undiyil, J.G., Stober, J., Besbelli, N. & Pronczuk, J. Acute pesticide poisoning:
a proposed classication tool. Bull. World Health Organ. 86, 205–209 (2008).
75. International Federation of Organic Agriculture Movements e IFOAM
Norms for Organic Production and Processing, Version 2014 (IFOAM, 2014);
www.ifoam.bio/en/ifoam-norms
76. USDA Agricultural Marketing Service National Organic Program Handbook
(USDA, 2015); available at www.ams.usda.gov/rules-regulations/organic/
handbook
77. Council of the European Union Council Regulation (EC) No 834/2007of
28June 2007on Organic Production and Labeling of Organic Products
and Repealing Regulation (EEC) No2092/91 (Ocial Journal of the
European Union, 2008); http://eur-lex.europa.eu/legal-content/EN/
NOT/?uri=CELEX:32007R0834
78. Japan Ministry of Agriculture, Forestry and Fisheries Notication No. 1608
Japanese Agricultural Standard for Organic Livestock Products (MAFF, 2012);
www.ma.go.jp/e/jas/specic/pdf/836_2012–2pdf
79. Parrott, N., Olesen, J.E. & Høgh-Jensen, H. in Global Development of
Organic Agriculture: Challenges and Prospects (eds Halberg, N. et al.) 153–179
(CABI, 2006).
80. Bachman, L., Cruzada, E. & Wright, S. Food Security and Farmer
Empowerment: A Study of the Impacts of Farmer-Led Sustainable Agriculture in
the Philippines (MASIPAG, 2009).
81. Reganold, J.P. etal. Transforming US agriculture. Science 332, 670–671 (2011).
82. Food and Agriculture Organization FAO Statistical Pocketbook 2015: World
Food and Agriculture (FAO, 2015).
83. World Health OrganizationObesity and Overweight, Fact Sheet #311(WHO,
2015); www.who.int/mediacentre/factsheets/fs311/en/
84. Food and Agriculture Organization, International Fund for Agricultural
Development & World Food Programme e State of Food Insecurity in the
World 2015 (FAO, 2015).
85. Jackson, L.L. Who “designs” the agricultural landscape? Landscape J.
27, 23–40 (2008).
86. Shari, O. etal. Barriers to conversion to organic farming: a case study in
Babol County in Iran. Afr. J.Agr. Res. 5, 2260–2267 (2010).
87. Constance, D. & Choi, J.Y. Overcoming the barriers to organic adoption
in the United States: a look at pragmatic conventional producers in Texas.
Sustainability 2, 163–188 (2010).
88. UNCTAD Trade and Environment Review 2013
(United Nations Publication, 2013).
89. Stolze, M. & Lampkin, N. Policy for organic farming: rationale and concepts.
Food Policy 34, 237–244 (2009).
90. Pretty, J. & Bharucha Z.P. Sustainable intensication in agricultural systems.
Ann. Bot. 114, 1571–1596 (2014).
91. Organisation for Economic Co-operation and Development Policy Instruments
to Support Green Growth in Agriculture (OECD Publishing, 2013).
92. Sanchez, P.A. Tripling crop yields in tropical Africa. Nature Geosci.
3, 299–300 (2010).
93. Oce of Communications Agriculture Secretary Vilsack unveils vision for US
organic agriculture. USDA News Release No. 0096.13 (2013); www.usda.gov/
wps/portal/usda/usdamedia?contentid=2013/05/0096.xml&printable=true
94. Reganold, J.P., Glover, J.D., Andrews, P.K. & Hinman, H.R. Sustainability of
three apple production systems. Nature 410, 926–930 (2001).
95. Davis, A.S., Hill, J.D., Chase, C.A., Johanns, A.M. & Liebman, M.,
Increasing cropping system diversity balances productivity, protability and
environmental health. PLoS One 7, e47149 (2012).
96. Wachter, J.M. & Reganold, J.P. in Encyclopedia of Agriculture and Food
Systems (ed. Van Alfen, N.) 265–286 (Elsevier, 2014).
97. Willer, H., Lernoud, J. & Kilcher, L. (eds) e World of Organic Agriculture:
Statistics and Emerging Trends 2013 (FiBL-IFOAM, 2013).
98. Willer, H. & Lernoud, J. (eds) e World of Organic Agriculture: Statistics and
Emerging Trends 2014 (FiBL-IFOAM, 2014).
99. Stockdale, E.A. etal. Agronomic and environmental implications of organic
farming systems. Adv. Agron. 70, 261–327 (2001).
100. Institute of Medicine & National Research Council A Framework for Assessing
Eects of the Food System (e National Academies, 2015).
Acknowledgements
J.M.W. is supported by NSF-IGERT (0903714) and USDA-NIFA (230470).
Author contributions
J.P.R. and J.M.W. contributed equally to the concept, outline and writing of the
manuscript, including generating the gures.
Additional information
Reprints and permissions information is available at www.nature.com/reprints.
Correspondence and requests for materials should be addressed to J.P.R.
Competing interests
e authors declare no competing nancial interests.
REVIEW ARTICLE NATURE PLANTS DOI: 10.1038/NPLANTS.2015.221
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