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Food Security: The Challenge of Feeding 9 Billion People


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Continuing population and consumption growth will mean that the global demand for food will increase for at least another 40 years. Growing competition for land, water, and energy, in addition to the overexploitation of fisheries, will affect our ability to produce food, as will the urgent requirement to reduce the impact of the food system on the environment. The effects of climate change are a further threat. But the world can produce more food and can ensure that it is used more efficiently and equitably. A multifaceted and linked global strategy is needed to ensure sustainable and equitable food security, different components of which are explored here.
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DOI: 10.1126/science.1185383
, 812 (2010); 327Science et al.H. Charles J. Godfray,
Food Security: The Challenge of Feeding 9 Billion
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Food Security: The Challenge of
Feeding 9 Billion People
H. Charles J. Godfray,
*John R. Beddington,
Ian R. Crute,
Lawrence Haddad,
David Lawrence,
James F. Muir,
Jules Pretty,
Sherman Robinson,
Sandy M. Thomas,
Camilla Toulmin
Continuing population and consumption growth will mean that the global demand for food will
increase for at least another 40 years. Growing competition for land, water, and energy, in addition to
the overexploitation of fisheries, will affect our ability to produce food, as will the urgent requirement
to reduce the impact of the food system on the environment. The effects of climate change are a
further threat. But the world can produce more food and can ensure that it is used more efficiently and
equitably. A multifaceted and linked global strategy is needed to ensure sustainable and equitable food
security, different components of which are explored here.
The past half-century has seen marked
growth in food production, allowing for a
dramatic decrease in the proportion of the
worlds people that are hungry, despite a doubling
of the total population (Fig. 1) (1,2). Neverthe-
less, more than one in seven people today still do
not have access to sufficient protein and energy
from their diet, and even more suffer from some
form of micronutrient malnourishment (3). The
world is now facing a new set of intersecting chal-
lenges (4). The global population will continue to
grow, yet it is likely to plateau at some 9 billion
people by roughly the middle of this century. A
major correlate of this deceleration in population
growth is increased wealth, and with higher pur-
chasing power comes higher consumption and a
greater demand for processed food, meat, dairy,
and fish, all of which add pressure to the food
supply system. At the same time, food producers
are experiencing greater competition for land,
water, and energy, and the need to curb the many
negative effects of food production on the envi-
ronment is becoming increasingly clear (5,6).
Overarching all of these issues is the threat of the
effects of substantial climate change and concerns
about how mitigation and adaptation measures
may affect the food system (7,8).
A threefold challenge now faces the world (9):
Match the rapidly changing demand for food
from a larger and more affluent population to its
supply; do so in ways that are environmentally
and socially sustainable; and ensure that the
worlds poorest people are no longer hungry.
This challenge requires changes in the way food
is produced, stored, processed, distributed, and
accessed that are as radical as those that occurred
during the 18th- and 19th-century Industrial and
Agricultural Revolutions and the 20th-century
Green Revolution. Increases in production will
have an important part to play, but they will be
constrained as never before by the finite resources
provided by Earths lands, oceans, and atmo-
sphere (10).
Patterns in global food prices are indicators of
trends in the availability of food, at least for those
who can afford it and have access to world mar-
kets. Over the past century, gross food prices have
generally fallen, leveling off in the past three dec-
ades but punctuated by price spikes such as that
caused by the 1970s oil crisis. In mid-2008, there
was an unexpected rapid rise in food prices, the
cause of which is still being debated, that subsided
when the world economy went into recession (11).
However, many (but not all) commentators have
predicted that this spike heralds a period of rising
and more volatile food prices driven primarily by
increased demand from rapidly developing coun-
tries, as well as by competition for resources from
first-generation biofuels production (12). Increased
food prices will stimulate greater investment in
food production, but the critical importance of food
to human well-being and also to social and po-
litical stability makes it likely that
governments and other organizations
will want to encourage food pro-
duction beyond that driven by sim-
ple market mechanisms (13). The
long-term nature of returns on in-
vestment for many aspects of food
production and the importance of
policies that promote sustainability
and equity also argue against purely
relying on market solutions.
So how can more food be pro-
duced sustainably? In the past, the
primary solution to food shortages
has been to bring more land into
agriculture and to exploit new fish
stocks. Yet over the past 5 decades,
while grain production has more
than doubled, the amount of land
devoted to arable agriculture global-
ly has increased by only ~9% (14).
Some new land could be brought
into cultivation, but the competi-
tion for land from other human ac-
tivities makes this an increasingly
unlikely and costly solution, par-
ticularly if protecting biodiversity
and the public goods provided by
natural ecosystems (for example,
carbon storage in rainforest) are
given higher priority (15). In recent
decades, agricultural land that was
formerly productive has been lost
to urbanization and other human
uses, as well as to desertification,
salinization, soil erosion, and other
consequences of unsustainable land
Department of Zoology and Institute of Biodiversity at the
James Martin 21st Century School, University of Oxford, South
Parks Road, Oxford OX1 3PS, UK.
U.K. Government Office for
Science, 1 Victoria Street, London SW1H OET, UK.
ture and Horticulture Development Board, Stoneleigh Park,
Kenilworth, Warwickshire CV8 2TL, UK.
Institute of Develop-
ment Studies, Falmer, Brighton BN1 9RE, UK.
Syngenta AG,
Post Office Box, CH-4002 Basel, Switzerland.
Institute of Aqua-
culture, University of Stirling, Stirling FK9 4LA, UK.
of Biological Sciences, University of Essex, Wivenhoe Park,
Colchester, Essex CO4 3SQ, UK.
Institute of Development
Studies, Falmer, Brighton BN1 9RE, UK.
Foresight, U.K. Gov-
ernment Office for Science, 1 Victoria Street, London SW1H
International Institute for Environment and Develop-
ment, 3 Endsleigh Street, London WC1H 0DD, UK.
*To whom correspondence should be addressed. E-mail:
Relative productionRelative numbers
1970 1980 1990 2000 2010
Main grains (wheat, barley,
maize, rice, oats)
Coarse grains
(millet, sorghum)
Cattle and buffalo
Sheep and goats
Root crops
(cassava, potato)
1960 1970 1980 1990 2000 2010
Fig. 1. Changes in the relative global production of crops and
animals since 1961 (when relative production scaled to 1 in
1961). (A) Major crop plants and (B)majortypesoflivestock.
[Source: (2)]
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management (16). Further losses, which may
be exacerbated by climate change, are likely
(7). Recent policy decisions to produce first-
generation biofuels on good quality agricultural
land have added to the competitive pressures
(17). Thus, the most likely scenario is that more
food will need to be produced from the same
amount of (or even less) land. Moreover, there
are no major new fishing grounds: Virtually all
capture fisheries are fully exploited, and most
are overexploited.
Recent studies suggest that the world will
need 70 to 100% more food by 2050 (1,18). In
this article, major strategies
for contributing to the chal-
lenge of feeding 9 billion
people, including the most
disadvantaged, are explored.
Particular emphasis is given
to sustainability, as well as
to the combined role of the
natural and social sciences
in analyzing and addressing
the challenge.
Closing the Yield Gap
There is wide geographic var-
iation in crop and livestock
productivity, even across re-
gions that experience similar
climates. The difference be-
tween realized productivity
and the best that can be
achieved using current ge-
netic material and available
technologies and manage-
ment is termed the yield
gap.The best yields that
can be obtained locally depend on the capacity
of farmers to access and use, among other things,
seeds, water, nutrients, pest management, soils,
biodiversity, and knowledge. It has been esti-
mated that in those parts of Southeast Asia
where irrigation is available, average maximum
climate-adjusted rice yields are 8.5 metric tons
per hectare, yet the average actually achieved
yields are 60% of this figure (19). Similar yield
gaps are found in rain-fed wheat in central Asia
and rain-fed cereals in Argentina and Brazil.
Another way to illustrate the yield gap is to
compare changes in per capita food production
over the past 50 years. In Asia, this amount has
increased approximately twofold (in China, by a
factor of nearly 3.5), and in Latin America, it has
increased 1.6-fold; in Africa, per capita produc-
tion fell back from the mid-1970s and has only
just reached the same level as in 1961 (2,20).
Substantially more food, as well as the income to
purchase food, could be produced with current
crops and livestock if methods were found to
close the yield gaps.
Low yields occur because of technical con-
straints that prevent local food producers from
increasing productivity or for economic reasons
arising from market conditions. For example,
farmers may not have access to the technical
knowledge and skills required to increase pro-
duction, the finances required to invest in higher
production (e.g., irrigation, fertilizer, machinery,
crop-protection products, and soil-conservation
measures), or the crop and livestock varieties
that maximize yields. After harvest or slaughter,
they may not be able to store the produce or
have access to the infrastructure to transport the
produce to consumer markets. Farmers may also
choose not to invest in improving agricultural
productivity because the returns do not compare
well with other uses of capital and labor.
Exactly how best to facilitate increased food
production is highly site-specific. In the most
extreme cases of failed states and nonfunction-
ing markets, the solution lies completely out-
side the food system. Where a functioning state
exists, there is a balance to be struck between
investing in overall economic growth as a spur
to agriculture and focusing on investing in ag-
riculture as a spur to economic growth, though
the two are obviously linked in regions, such as
sub-Saharan Africa, where agriculture typically
makes up 20 to 40% gross domestic product.
In some situations, such as low-income food-
importing countries, investing purely in generat-
ing widespread income growth to allow food
purchases from regions and countries with bet-
ter production capabilities may be the best
choice. When investment is targeted at food
production, a further issue is the balance be-
tween putting resources into regional and na-
tional infrastructure, such as roads and ports,
and investing in local social and economic
capital (21,22).
A yield gap may also exist because the high
costs of inputs or the low returns from increased
production make it economically suboptimal to
raise production to the maximum technically at-
tainable. Poor transport and market infrastruc-
ture raise the prices of inputs, such as fertilizers
and water, and increase the costs of moving the
food produced into national or world markets.
Where the risks of investment are high and the
means to offset them are absent, not investing
can be the most rational decision, part of the
poverty trap.Food production in developing
countries can be severely affected by market
interventions in the developed
world, such as subsidies or price
supports. These need to be care-
fully designed and implemented
so that their effects on global
commodity prices do not act as
disincentives to production in
other countries (23).
The globalization of the
food system offers some local
food producers access to larger
markets, as well as to capital
for investment. At the aggre-
gate level, it also appears to
increase the global efficiency
of food production by allowing
regional specialization in the
production of the locally most
appropriate foods. Because the
expansion of food production
and the growth of population
both occur at different rates in
different geographic regions,
global trade is necessary to ba-
lance supply and demand across
regions. However, the environmental costs of
food production might increase with globaliza-
tion, for example, because of increased greenhouse
gas emissions associated with increased produc-
tion and food transport (24). An unfettered mar-
ket can also penalize particular communities and
sectors, especially the poorest who have the least
influence on how global markets are structured
and regulated. Expanded trade can provide insur-
ance against regional shocks on production such
as conflict, epidemics, droughts, or floodsshocks
that are likely to increase in frequency as climate
change occurs. Conversely, a highly connected
food system may lead to the more widespread
propagation of economic perturbations, as in the
recent banking crisis, thus affecting more peo-
ple. There is an urgent need for a better under-
standing of the effects of globalization on the
full food system and its externalities.
The yield gap is not static. Maintaining, let
alone increasing, productivity depends on con-
tinued innovation to control weeds, diseases, in-
sects, and other pests as they evolve resistance
to different control measures, or as new spe-
cies emerge or are dispersed to new regions.
Box 1. Sustainable intensification.
Producing more food from the same area of land while reducing the environmental
impacts requires what has been called sustainable intensification(18). In exactly the
same way that yields can be increased with the use of existing technologies, many
options currently exist to reduce negative externalities (47). Net reductions in some
greenhouse gas emissions can potentially be achieved by changing agronomic
practices, the adoption of integrated pest management methods, the integrated
management of waste in livestock production, and the use of agroforestry. However,
the effects of different agronomic practices on the full range of greenhouse gases can
be very complex and may depend on the temporal and spatial scale of measurement.
More research is required to allow a better assessment of competing policy options.
Strategies such as zero or reduced tillage (the reduction in inversion ploughing),
contour farming, mulches, and cover crops improve water and soil conservation, but
they may not increase stocks of soil carbon or reduce emissions of nitrous oxide.
Precision agriculture refers to a series of technologies that allow the application of
water, nutrients, and pesticides only to the places and at the times they are required,
thereby optimizing the use of inputs (48). Finally, agricultural land and water bodies
used for aquaculture and fisheries can be managed in ways specifically designed to
reduce negative impacts on biodiversity. SCIENCE VOL 327 12 FEBRUARY 2010 813
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Innovation involves both traditional and ad-
vanced crop and livestock breeding, as well as
the continuing development of better chemical,
agronomic, and agro-ecological control mea-
sures. The maximum attainable yield in different
regions will also shift as the effects of climate
change are felt. Increasing atmospheric CO
els can directly stimulate crop growth, though
within the context of real agricultural production
systems, the magnitude of this effect is not clear
(7). More important will be the ability to grow
crops in places that are currently unsuitable, par-
ticularly the northern temperate regions (though
expansion of agriculture at the expense of boreal
forest would lead to major greenhouse gas emis-
sions), and the loss of currently productive re-
gions because of excessively high temperatures
and drought. Models that couple the physics of
climate change with the biology of crop growth
will be important to help policy-makers antici-
pate these changes, as well as to evaluate the role
of agricultural biodiversityin helping mitigate
their effects (25).
Closing the yield gap would dramatically
increase the supply of food, but with uncertain
impacts on the environment and potential feed-
backs that could undermine future food produc-
tion. Food production has important negative
externalities,namely effects on the environment
or economy that are not reflected in the cost of
food. These include the release of greenhouse
gases [especially methane and nitrous oxide,
which are more damaging than CO
and for
which agriculture is a major source (26)], envi-
ronmental pollution due to nutrient run-off, water
shortages due to overextraction, soil degrada-
tion and the loss of biodiversity through land
conversion or inappropriate management, and
ecosystem disruption due to the intensive har-
vesting of fish and other aquatic foods (6).
To address these negative effects, it is now
widely recognized that food production systems
and the food chain in general must become fully
sustainable (18). The principle of sustainability
implies the use of resources at rates that do not
exceed the capacity of Earth to replace them.
By definition, dependency on nonrenewable
inputs is unsustainable, even if in the short
term it is necessary as part of a trajectory toward
There are many difficulties in making sustain-
ability operational. Over what spatial scale should
food production be sustainable? Clearly an over-
arching goal is global sustainability, but should
this goal also apply at lower levels, such as re-
gions (or oceans), nations, or farms? Could high
levels of consumption or negative externalities
in some regions be mitigated by improvements
in other areas, or could some unsustainable
activities in the food system be offset by actions
in the nonfood sector (through carbon-trading,
for example)? Though simple definitions of
sustainability are independent of time scale, in
practice, how fast should we seek to move from
the status quo to a sustainable food system? The
challenges of climate change and competition
for water, fossil fuels, and other resources suggest
that a rapid transition is essential. Nevertheless,
it is also legitimate to explore the possibility that
superior technologies may become available and
that future generations may be wealthier and,
hence, better able to absorb the costs of the tran-
sition. Finally, we do not yet have good enough
metrics of sustainability, a major problem when
evaluating alternative strategies and negotiat-
ing trade-offs. This is the case for relatively cir-
cumscribed activities, such as crop production
on individual farms, and even harder when the
complete food chain is included or for complex
products that may contain ingredients sourced
from all around the globe. There is also a danger
that an overemphasis on what can be measured
relatively simply (carbon, for example) may lead
to dimensions of sustainability that are harder
to quantify (such as biodiversity) being ignored.
These are areas at the interface of science, en-
gineering, and economics that urgently need more
attention (see Box 1). The introduction of mea-
sures to promote sustainability does not neces-
sarily reduce yields or profits. One study of 286
agricultural sustainability projects in developing
countries, involving 12.6 million chiefly small-
holder farmers on 37 million hectares, found an
average yield increase of 79% across a very wide
varietyofsystemsandcroptypes(27). One-quarter
of the projects reported a doubling of yield. Re-
search on the ability of these and related pro-
grams to be scaled up to country and regional
levels should be a priority (Fig. 2).
Strategies designed to close the yield gap in
the poorest countries face some particular chal-
lenges (28). Much production is dominated by
small-holder agriculture with women often taking
a dominant role in the workforce. Where viable,
investment in the social and economic mecha-
nisms to enable improved small-holder yields,
especially where targeted at women, can be im-
portant means of increasing the income of both
farm and rural nonfarm households. The lack of
secure land rights can be a particular problem for
many poor communities, may act as a disincen-
tive for small holders to invest in managing the
land more productively, and may make it harder
to raise investment capital (29). In a time of ris-
ing prices for food and land, it can also render
these communities vulnerable to displacement by
more powerful interest groups. Where the polit-
ical will and organizational infrastructure exist,
title definition and protection could be greatly
assisted by the application of modern informa-
tion and communication technologies. Even so,
there will be many people who cannot afford to
purchase sufficient calories and nutrients for a
healthy life and who will require social protection
programs to increase their ability to obtain food.
However, if properly designed, these programs
can help stimulate local agriculture by providing
small holders with increased certainty about the
demand for their products.
Fig. 2. An example of a major successful sustainable agriculture project. Niger was strongly affected by
a series of drought years in the 1970s and 1980s and by environmental degradation. From the early
1980s, donors invested substantially in soil and water conservation. The total area treated is on the
order of 300,000 ha, most of which went into the rehabilitation of degraded land. The project in the
Illela district of Niger promoted simple water-harvesting techniques. Contour stone bunds, half moons,
stone bunding, and improved traditional planting pits (zaı¨) were used to rehabilitate barren, crusted
land. More than 300,000 ha have been rehabilitated, and crop yields have increased and become more
stable from year to year. Tree cover has increased, as shown in the photographs. Development of the
land market and continued incremental expansion of the treated area without further project assistance
indicate that the outcomes are sustainable (51,52).
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There is also a role for large-scale farming
operations in poor-country agriculture, though the
value and contexts in which this is feasible are
much debated (30). This debate has been fanned
by a substantial increase in the number of sov-
ereign wealth funds, companies, and individuals
leasing, purchasing, or attempting to purchase
large tracts of agricultural land in developing
countries. This external investment in developing-
country agriculture may bring major benefits,
especially where investors bring considerable
improvements to crop production and process-
ing, but only if the rights and welfare of the
tenants and existing resource users are properly
addressed (31).
Many of the very poorest people live in areas
so remote that they are effectively disconnected
from national and world food markets. But for
others, especially the urban poor, higher food
prices have a direct negative effect on their ability
to purchase a healthy diet. Many rural farmers
and other food producers live near the margin of
being net food consumers and producers and will
be affected in complex ways by rising food prices,
with some benefitting and some being harmed
(21). Thus, whereas reducing distorting agricul-
tural support mechanisms in developed countries
and liberalizing world trade should stimulate
not everyone will gain (23,32). Better models
that can more accurately predict these complex
interactions are urgently needed.
Increasing Production Limits
The most productive crops, such as sugar cane,
growing in optimum conditions, can convert solar
energy into biomass with an efficiency of ~2%,
metric tons per hectare) (33). There is much de-
bate over exactly what the theoretical limits are
for the major crops under different conditions, and
similarly, for the maximum yield that can be ob-
tained for livestock rearing (18). However, there is
clearly considerable scope for increasing produc-
tion limits.
The Green Revolution succeeded by using
conventional breeding to develop F
hybrid vari-
eties of maize and semi-dwarf, disease-resistant
varieties of wheat and rice. These varieties could
be provided with more irrigation and fertilizer
(20) without the risk of major crop losses due to
lodging (falling over) or severe rust epidemics.
Increased yield is still a major goal, but the im-
portance of greater water- and nutrient-use effi-
ciency, as well as tolerance of abiotic stress, is
also likely to increase. Modern genetic techniques
and a better understanding of crop physiology al-
low for a more directed approach to selection
across multiple traits. The speed and costs at which
genomes today can be sequenced or resequenced
now means that these techniques can be more
easily applied to develop varieties of crop species
that will yield well in challenging environments.
These include crops such as sorghum, millet, cas-
sava, and banana, species that are staple foods for
many of the worlds poorest communities (34).
Currently, the major commercialized geneti-
cally modified (GM) crops involve relatively sim-
ple manipulations, such as the insertion of a gene
for herbicide resistance or another for a pest-insect
toxin. The next decade will see the development
of combinations of desirable traits and the intro-
duction of new traits such as drought tolerance.
By mid-century, much more radical options in-
volving highly polygenic traits may be feasible
(Table 1). Production of cloned animals with en-
gineered innate immunity to diseases that reduce
production efficiency has the potential to reduce
substantial losses arising from mortality and
subclinical infections. Biotechnology could also
produce plants for animal feed with modified
composition that increase the efficiency of meat
production and lower methane emissions.
Domestication inevitably means that only a
subset of the genes available in the wild-species
progenitor gene pool is represented among crop
varieties and livestock breeds. Unexploited ge-
netic material from land races, rare breeds, and
wild relatives will be important in allowing
breeders to respond to new challenges. Interna-
tional collections and gene banks provide val-
uable repositories for such genetic variation, but
it is nevertheless necessary to ensure that locally
adapted crop and livestock germplasm is not lost
in the process of their displacement by modern,
improved varieties and breeds. The trend over
recent decades is of a general decline in invest-
ment in technological innovation in food produc-
tion (with some notable exceptions, such as in
China and Brazil) and a switch from public to
private sources (1). Fair returns on investment are
essential for the proper functioning of the pri-
vate sector, but the extension of the protection
of intellectual property rights to biotechnology
has led to a growing public perception in some
countries that biotech research purely benefits
commercial interests and offers no long-term
public good. Just as seriously, it also led to a
virtual monopoly of GM traits in some parts of
the world, by a restricted number of companies,
which limits innovation and investment in the
technology. Finding ways to incentivize wide ac-
cess and sustainability, while encouraging a com-
petitive and innovative private sector to make
best use of developing technology, is a major
governance challenge.
The issue of trust and public acceptance of
biotechnology has been highlighted by the debate
over the acceptance of GM technologies. Because
genetic modification involves germline modifi-
cation of an organism and its introduction to the
environment and food chain, a number of par-
ticular environmental and food safety issues need
to be assessed. Despite the introduction of rig-
orous science-based risk assessment, this discus-
sion has become highly politicized and polarized
in some countries, particularly those in Europe.
Our view is that genetic modification is a poten-
tially valuable technology whose advantages and
disadvantages need to be considered rigorously
on an evidential, inclusive, case-by-case basis:
Genetic modification should neither be privileged
nor automatically dismissed. We also accept the
Table 1. Examples of current and potential future applications of GM technology for crop genetic
improvement. [Source: (18,49)]
Time scale Target crop trait Target crops
Current Tolerance to broad-spectrum
Maize, soybean, oilseed
Resistance to chewing insect
Maize, cotton, oilseed
(510 years)
Nutritional bio-fortification Staple cereal crops, sweet
Resistance to fungus and virus
Potato, wheat, rice, banana,
fruits, vegetables
Resistance to sucking insect pests Rice, fruits, vegetables
Improved processing and storage Wheat, potato, fruits,
Drought tolerance Staple cereal and tuber crops
(1020 years)
Salinity tolerance Staple cereal and tuber crops
Increased nitrogen-use
High-temperature tolerance
(>20 years)
apomixis Staple cereal and tuber crops
Nitrogen fixation
Denitrification inhibitor
Conversion to perennial habit
Increased photosynthetic efficiency SCIENCE VOL 327 12 FEBRUARY 2010 815
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need for this technology to gain greater public
acceptance and trust before it can be considered
as one among a set of technologies that may
contribute to improved global food security.
There are particular issues involving new
technologies, both GM and non-GM, that are
targeted at helping the least-developed countries
(35,36). The technologies must be directed at
the needs of those communities, which are often
different from those of more developed country
farmers. To increase the likelihood that new tech-
nology works for, and is adopted by, the poorest
nations, they need to be involved
in the framing, prioritization, risk
assessment, and regulation of inno-
vations. This will often require the
creation of innovative institutional
and governance mechanisms that ac-
count for socio-cultural context (for
example, the importance of women
in developing-country food produc-
tion). New technologies offer major
promise, but there are risks of lost
trust if their potential benefits are
exaggerated in public debate. Efforts
to increase sustainable production
limits that benefit the poorest nations
will need to be based around new
alliances of businesses, civil society
organizations, and governments.
Reducing Waste
Roughly 30 to 40% of food in both
the developed and developing worlds
is lost to waste, though the causes
behind this are very different (Fig. 3)
(16,3739). In the developing world,
losses are mainly attributable to the absence of
food-chain infrastructure and the lack of knowl-
edge or investment in storage technologies on
the farm, although data are scarce. For example,
in India, it is estimated that 35 to 40% of fresh
produce is lost because neither wholesale nor
retail outlets have cold storage (16). Even with
rice grain, which can be stored more readily, as
much as one-third of the harvest in Southeast
Asia can be lost after harvest to pests and spoil-
age (40). But the picture is more complex than
a simple lack of storage facilities: Although
storage after harvest when there is a glut of
food would seem to make economic sense, the
farmer often has to sell immediately to raise
In contrast, in the developed world, pre-retail
losses are much lower, but those arising at the
retail, food service, and home stages of the food
chain have grown dramatically in recent years,
for a variety of reasons (41). At present, food is
relatively cheap, at least for these consumers,
which reduces the incentives to avoid waste. Con-
sumers have become accustomed to purchasing
foods of the highest cosmetic standards; hence,
retailers discard many edible, yet only slightly
blemished products. Commercial pressures can
encourage waste: The food service industry fre-
quently uses super-sizedportions as a compet-
itive lever, whereas buy one get one freeoffers
have the same function for retailers. Litigation
and lack of education on food safety have lead
to a reliance on use bydates, whose safety
margins often mean that food fit for consump-
tion is thrown away. In some developed
countries, unwanted food goes to a landfill
instead of being used as animal feed or compost
because of legislation to control prion diseases.
Different strategies are required to tackle the
two types of waste. In developing countries, pub-
lic investment in transport infrastructure would
reduce the opportunities for spoilage, whereas
better-functioning markets and the availability
of capital would increase the efficiency of the
food chain, for example, by allowing the intro-
duction of cold storage (though this has implica-
tions for greenhouse gas emissions) (38). Existing
technologies and best practices need to be spread
by education and extension services, and market
and finance mechanisms are required to protect
farmers from having to sell at peak supply, lead-
ing to gluts and wastage. There is also a need for
continuing research in postharvest storage tech-
nologies. Improved technology for small-scale
food storage in poorer contexts is a prime can-
didate for the introduction of state incentives for
private innovation, with the involvement of small-
scale traders, millers, and producers.
If food prices were to rise again, it is likely
waste produced by consumers in developed coun-
tries. Waste may also be reduced by alerting con-
sumers to the scale of the issue, as well as to
domestic strategies for reducing food loss. Ad-
vocacy, education, and possibly legislation may
also reduce waste in the food service and retail
sectors. Legislation such as that on sell-by dates
and swill that has inadvertently increased food
waste should be reexamined within a more in-
clusive competing-risks framework. Reducing
developed-country food waste is particularly chal-
lenging, as it is so closely linked to individual
behavior and cultural attitudes toward food.
Changing Diets
The conversion efficiency of plant into animal
matter is ~10%; thus, there is a prima facie case
that more people could be supported from the
same amount of land if they were vegetarians.
About one-third of global cereal production is fed
to animals (42). But currently, one of the major
challenges to the food system is the rapidly in-
creasing demand for meat and dairy products that
has led, over the past 50 years, to a ~1.5-fold
increase in the global numbers of cattle, sheep,
and goats, with equivalent increases of ~2.5- and
~4.5-fold for pigs and chickens, respectively (2)
(Fig. 1). This is largely attributable to the increased
wealth of consumers everywhere and most re-
cently in countries such as China and India.
However, the argument that all meat con-
sumption is bad is overly simplistic. First, there
is substantial variation in the production effi-
ciency and environmental impact of the major
classes of meat consumed by people (Table 2).
Second, although a substantial fraction of live-
stock is fed on grain and other plant protein that
could feed humans, there remains a very sub-
stantial proportion that is grass-fed. Much of the
grassland that is used to feed these animals
could not be converted to arable land or could
only be converted with majorly adverse environ-
mental outcomes. In addition, pigs and poultry
are often fed on human food waste.Third,
through better rearing or improved breeds, it
may be possible to increase the efficiency with
which meat is produced. Finally, in developing
countries, meat represents the most concentrated
source of some vitamins and minerals, which is
important for individuals such as young children.
Livestock also are used for ploughing and trans-
port, provide a local supply of manure, can be a
vital source of income, and are of huge cultural
importance for many poorer communities.
Reducing the consumption of meat and in-
creasing the proportion that is derived from the
most efficient sources offer an opportunity to feed
more people and also present other advantages
(37). Well-balanced diets rich in grains and other
vegetable products are considered to be more
healthful than those containing a high proportion
of meat (especially red meat) and dairy products.
As developing countries consume more meat in
combination with high-sugar and -fat foods, they
may find themselves having to deal with obesity
before they have overcome undernutrition, lead-
50% 100%0%
On-farm Transport and processing
Food Service Home and municipal
Fig. 3. Makeup of total food waste in developed and develop-
ing countries. Retail, food service, and home and municipal
categories are lumped together for developing countries.
[Source: (16,3739)]
on February 18, 2010 www.sciencemag.orgDownloaded from
otherwise be used to alleviate poverty. Livestock
production is also a major source of methane, a
very powerful greenhouse gas, though this can
be partially offset by the use of animal manure
to replace synthetic nitrogen fertilizer (43). Of
the five strategies we discuss here, assessing the
value of decreasing the fraction of meat in our
diets is the most difficult and needs to be better
Expanding Aquaculture
Aquatic products (mainly fish, aquatic molluscs,
and crustaceans) have a critical role in the food
system, providing nearly 3 billion people with at
least 15% of their animal protein intake (44).
In many regions, aquaculture has been suffi-
ciently profitable to permit strong growth; repli-
cating this growth in areas such as Africa where
it has not occurred could bring major benefits.
Technical advances in hatchery systems, feeds
and feed-delivery systems, and disease manage-
ment could all increase output. Future gains may
also come from better stock selection, larger-
scale production technologies, aquaculture in
open seas and larger inland water bodies, and
the culture of a wider range of species. The long
production cycle of many species (typically 6 to
24 months) requires a financing system that is
capable of providing working capital as well as
offsetting risk. Wider production options (such as
temperature and salinity tolerance and disease
resistance) and cheaper feed substrates (for in-
stance, plant material with enhanced nutritional
features) might also be accessed with the use of
GM technologies.
Aquaculture may cause harm to the environ-
ment because of the release into water bodies
of organic effluents or disease treatment chem-
icals, indirectly through its dependence on in-
dustrial fisheries to supply feeds, and by acting
as a source of diseases or genetic contamination
for wild species. Efforts to reduce these negative
externalities and increase the efficiency of re-
source use [such as the fish intofish out ratio
(45)] have been spurred by the rise of sustain-
ability certification programs, though these mainly
affect only higher-value sectors. Gains in sustain-
ability could come from concentrating on lower
trophic level species and in integrating aquatic
and terrestrial food production, for example, by
using waste from the land as food and nutri-
ents. It will also be important to take a more
strategic approach to site location and capacity
within catchment or coastal zone management
units (46).
There is no simple solution to sustainably feed-
ing 9 billion people, especially as many become
increasingly better off and converge on rich-
country consumption patterns. A broad range of
options, including those we have discussed here,
needs to be pursued simultaneously. We are
hopeful about scientific and technological inno-
vation in the food system, but not as an excuse
to delay difficult decisions today.
Any optimism must be tempered by the
enormous challenges of making food produc-
tion sustainable while controlling greenhouse
gas emission and conserving dwindling water
supplies, as well as meeting the Millennium De-
velopment Goal of ending hunger. Moreover, we
must avoid the temptation to further sacrifice
Earths already hugely depleted biodiversity for
easy gains in food production, not only because
biodiversity provides many of the public goods
on which mankind relies but also because we do
not have the right to deprive future generations of
its economic and cultural benefits. Together, these
challenges amount to a perfect storm.
Navigating the storm will require a revolution
in the social and natural sciences concerned with
food production, as well as a breaking down of
barriers between fields. The goal is no longer
simply to maximize productivity, but to optimize
across a far more complex landscape of produc-
tion, environmental, and social justice outcomes.
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systems on water use, grain requirement, and methane production. Service water is that required for
cleaning and washing livestock housing and other facilities. Dashes indicate combinations for which no
data are available (either because it cannot be measured or because the combination does not exist).
This table does not include other impacts of differing livestock management systems such as (i) nutrient
run-off and pollution to surface and groundwater, (ii) protozoan and bacterial contamination of water
and food, (iii) antibiotic residues in water and food, (iv) heavy metal from feed in soils and water, (v)
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Water Measure of water use Grazing Intensive
Liters day
per animal at 15°C
Cattle Drinking water: all 22 103
Service water: beef 5 11
Service water: dairy 5 22
Pigs (lactating adult) Drinking water 17 17
Service water 25 125
Sheep (lactating adult) Drinking water 9 9
Service water 5 5
Chicken (broiler and layer) Drinking water 1.31.8 1.31.8
Service water 0.090.15 0.090.15
Feed required to produce 1 kg of meat kg of cereal per animal
Cattle 8
Pigs 4
Chicken (broiler) 1
Methane emissions from cattle kg of CH
per animal year
Cattle: dairy (U.S., Europe) 117128
Cattle: beef, dairy (U.S., Europe) 5360
Cattle: dairy (Africa, India) 4558
Cattle: grazing (Africa, India) 2731 SCIENCE VOL 327 12 FEBRUARY 2010 817
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53. The authors are members of the U.K. Government
Office for Sciences Foresight Project on Global Food and
Farming Futures. J.R.B. is also affiliated with Imperial
College London. D.L. is a Board Member of Plastid AS
(Norway) and owns shares in AstraZeneca Public Limited
Company and Syngenta AG. We are grateful to J. Krebs
and J. Ingrahm (Oxford), N. Nisbett and D. Flynn
(Foresight), and colleagues in Defra and DflD for their
helpful comments on earlier drafts of this manuscript.
If not for his sad death in July 2009, professor Mike Gale
(John Innes Institute, Norwich, UK) would also have been
an author of this paper.
Breeding Technologies to Increase
Crop Production in a Changing World
Mark Tester*and Peter Langridge
To feed the several billion people living on this planet, the production of high-quality food must
increase with reduced inputs, but this accomplishment will be particularly challenging in the face of
global environmental change. Plant breeders need to focus on traits with the greatest potential to
increase yield. Hence, new technologies must be developed to accelerate breeding through improving
genotyping and phenotyping methods and by increasing the available genetic diversity in breeding
germplasm. The most gain will come from delivering these technologies in developing countries, but
the technologies will have to be economically accessible and readily disseminated. Crop improvement
through breeding brings immense value relative to investment and offers an effective approach to
improving food security.
Although more food is needed for the rapidly
growing human population, food quality
also needs to be improved, particularly for
increased nutrient content. In addition, agricul-
tural inputs must be reduced, especially those of
nitrogenous fertilizers, if we are to reduce en-
vironmental degradation caused by emissions
of CO
and nitrogenous compounds from agri-
cultural processes. Furthermore, there are now
concerns about our ability to increase or even
sustain crop yield and quality in the face of dy-
namic environmental and biotic threats that will
be particularly challenging in the face of rapid
global environmental change. The current di-
version of substantial quantities of food into the
production of biofuels puts further pressure on
world food supplies (1).
Breeding and agronomic improvements have,
on average, achieved a linear increase in food
production globally, at an average rate of 32 million
metric tons per year (2) (Fig. 1). However, to meet
the recent Declaration of the World Summit on
Food Security (3) target of 70% more food by
2050, an average annual increase in production of
44 million metric tons per year is required (Fig. 1),
representing a 38% increase over historical
increases in production, to be sustained for 40
years. This scale of sustained increase in global
food production is unprecedented and requires
substantial changes in methods for agronomic
processes and crop improvement. Achieving this
increase in food production in a stable environment
would be challenging, but is undoubtedly much
more so given the additional pressures created
by global environmental changes.
Global Environmental Change Alters
Breeding Targets
Certain aspects of global environmental change
are beneficial to agriculture. Rising CO
acts as a
fertilizer for C3 crops and is estimated to account
for approximately 0.3% of the observed 1% rise in
global wheat production (4), although this benefit
is likely to diminish, because rising temperatures
will increase photorespiration and nighttime res-
piration. A benefit of rising temperatures is the
alleviation of low-temperature inhibition of growth,
which is a widespread limitation at higher latitudes
and altitudes. Offsetting these benefits, however,
are obvious deleterious changes, such as an in-
creased frequency of damaging high-temperature
events, new pest and disease pressures, and al-
tered patterns of drought. Negative effects of other
pollutants, notably ozone, will also reduce benefits
to plant growth from rising CO
and temperature.
Particularly challenging for society will be
changes in weather patterns that will require
alterations in farming practices and infrastructure;
for example, water storage and transport networks.
Because one-third of the worldsfoodisproduced
on irrigated land (5,6), the likely impacts on
global food production are many. Along with
agronomic- and management-based approaches to
improving food production, improvements in a
crops ability to maintain yields with lower water
supply and quality will be critical. Put simply, we
need to increase the tolerance of crops to drought
and salinity.
In the context of global environmental change,
the efficiency of nitrogen use has also emerged as
a key target. Human activity has already more
than doubled the amount of atmospheric N
Australian Centre for Plant Functional Genomics, University of
Adelaide, South Australia SA 5064, Australia.
*To whom correspondence should be addressed. E-mail:
12 FEBRUARY 2010 VOL 327 SCIENCE www.sciencemag.org818
on February 18, 2010 www.sciencemag.orgDownloaded from
... As climate change advances, improving crop drought tolerance will be key for ensuring food 37 security (1,2). This has led to intense research at the molecular level to find novel loci and 38 alleles that drive plant drought responses. ...
Full-text available
Simple, soil-free assays that can mimic drought conditions are incredibly useful for investigating plant stress responses. Due to their ease of use, the research community often relies on polyethylene glycol (PEG), mannitol and salt treatments to simulate drought conditions in the laboratory. However, while these types of osmotic stress can create phenotypes that resemble those of drought, it remains unclear how they compare at the molecular level. Here, using transcriptomics, we demonstrate that these assays are unable to replicate drought signaling responses in the Arabidopsis root. Indeed, we found a significant number of genes that were induced by drought were in fact repressed by such treatments. Since our results question the utility of PEG, mannitol and salt, we designed a new method for simulating drought. By simply adding less water to agar, our 'low-water agar' assay elicits gene expression responses that compare more favorably to drought stress. Furthermore, we show our approach can be leveraged as a high-throughput assay to investigate natural variation in drought responses.
In recent years it has been stressed that the problems created by population growth and climate change are so big and of such complexity that we do not have the capacity to address them. We do not react to a cascade of situations that are driving us to absolute collapse for two reasons: (1) The mental short-termism that is inherent in any animal, including the human being, (2) the synergy of factors that act together, not being able to isolate each other to give partial solutions. In this puzzle, the oceans, after decades of being ignored, seem to take on rele�vance. The UN launched a plan to draw attention to the role of that 70% mass of water that covers the surface of our planet, finally coming to the conclusion that part of the solution lies in understanding, managing and restoring the oceans. Biodi�versity, complexity, and functionality take on relevance in one of the Sustainable Development Goals that aims to improve our oceans. Life Below Water (SDG 14) is one of the goals to be achieved in this desperate decade, in which we are going to have to race to try to save civilization in its many facets. A Decade of the Oceans has been instituted that aims to channel the greatest possible number of initiatives to substantially improve the health of marine habitats, as well as try to mitigate the impact on human communities. Fisheries, pollution, and urban expansion are some direct issues that are stressing the oceans, but we may have direct (local and regional) solutions to solve them in many cases. However, among all the challenges we face, the most global and complex one to mitigate is climate change. In the oceans, climate change is especially evident, since 93% of the heat absorbed by the earth is concentrated in the water masses that are warming rapidly. Acidification, which is the sister of warming in water masses due to the increase in CO2 that penetrates and reacts to create slightly less alkaline water, is the other large-scale problem that has a global impact and cannot be controlled locally. Marine organisms suffer these consequences, having to adapt, migrate or disappear. We have created a transition phase to a new unknown state in which some species, habitats and even biomes will prevail while others languish or simply disappear. Understanding, managing and repairing our actions in the oceans has become a very urgent task to solve the problem and understand how long this transition between systems will last. This book focuses, in seven chapters, on the perspectives and solutions that different research groups offer to try to address problems related to SDG 14: Life Below Water. The different objectives developed in SDG 14 are treated indepen�dently, with an attempt to give a global vision of the issues. The mechanism used to select the book’s content was through an Artificial Intelligence program, choosing articles related to the topics by means of keywords. The program selected those arti�cles, and those that were not related to the topic or did not focus on SDG 14 were discarded. Obviously, the selection was partial and the entire subject is not covered, but the final product gives a very solid idea of how to orient ourselves to delve deeper into the topic of SDG 14 using published chapters and articles. The AI program itself selected the text of these contributions to show the progress in different topics related to SDG 14. This mode of operation will allow specialists (and non-specialists) to collect useful information for their specific research purposes in a short period of time. At a time when information is essential in order to move quickly by providing concrete answers to complex problems, this type of approach will become essential for researchers, especially for a subject as vast as SDG 14.
Rapid urbanization and industrialization have resulted in an increased global temperature over the year. Consequently, the agro-ecological system disturbing worldwide. Therefore, new agricultural practices that are eco-friendly are needed. Mulching could potentially serve the purpose by conserving moisture, reducing weed growth, reducing soil evaporation, improving microbial activities and controlling soil temperature. Additionally, mulches could provide environmental and economical advantages to agriculture and landscape and enhance the nutrient status in soil. This review chapter focuses on multiple significant impacts of mulches on nutrient use efficiencies in the plant. Secondly, discuss problems regarding nutrients use efficiencies and loss of nutrient from soil system and also discussed strategies to improving nutrient use efficiencies. This discussion leads to improve the nutrients use efficiencies in the plant by mulching.
Full-text available
Possibilities to combine augmentative biological control using Trichogramma spp. egg parasitoids and conservation biological control through habitat manipulation, for the management of rice leaffolder and rice stemborer pests have received only cursory mention in the literature. We reviewed information on the use of Trichogramma releases and on habitat manipulation to manage leaffolders and stemborers in rice. Stemborers have become a priority for biological control since the 1990s with research focusing mainly on Chilo suppressalis in China and Iran, Scirpophaga incertulas in South and Southeast Asia, and Chilo agamemnon in Egypt. In most cases, 100 K wasps (T. japonicum or T. chilonis) released over 30–100 release points ha−1 at least once during early crop stages, resulted in good control (>50% reduction in damage). Despite positive results accumulated over decades, larger scale releases in rice have only been conducted very recently. Research on conservation biological control of stemborers has focused on manipulating rice field habitat, particularly along rice bunds (levees). Several studies reported higher Trichogramma densities or greater egg parasitism in rice fields with flowering plants on bunds compared to control fields (without bund vegetation and usually with insecticides). These trends have mainly been attributed to nectar as a supplementary food for the adult wasps, although evidence for this mechanism is weak. Trap plants, such as vetiver grass (Chrysopogon zizanioides) attract ovipositing stemborers, but suppress larval development. Repellent and banker plants have not yet been identified for rice stemborers or leaffolders. We outline the opportunities and challenges for combining augmentative and conservation biological control of leaffolders and stemborers in rice.
In the Yellow River Delta, soil salinization and river sediment are the two factors influence on economic growth. A large area of salinization reduces crop yields and dredged river sediment increases management costs. This study evaluated the effects of applying sediments under different levels of irrigation on salinity leaching for improving field productivity. A three-year field experiment (from June 2017 to June 2020) was conducted by considering three levels of sediment application:a control (no sediment added, S1), 30▒mm ha⁻¹ (S2) and 60▒mm ha⁻¹ (S3), and three levels of irrigation water: 290▒mm (90▒mm maize + 200▒mm wheat, W1), 385▒mm (120▒mm maize + 265▒mm wheat, W2) and 480▒mm (150▒mm maize + 330▒mm wheat, W3). The results exhibited that soil leaching rate was up to 66.3 % under 60▒mm ha⁻¹ sediment application and 385▒mm irrigation after three wheat-maize rotation cultivation. This irrigation and sediment applied strategy achieved the effect of leaching salt, saving water and increasing grain yields. The mean yield of wheat and maize in sediment application and irrigation treatment was 18.3▒t ha⁻¹ in three-year experiment which was significant bigger than the control. Thus, it is a technically feasible and friendly sustainable approach for salinization soil development in the Yellow River Delta.
Full-text available
Artificial upwelling brings nutrient-rich deep water to the sun-lit surface to boost fisheries or carbon sequestration. Deep water sources under consideration range widely in inorganic silicon (Si) relative to nitrogen (N). Yet, little is known about how such differences in nutrient composition may influence the effectiveness of the fertilization. Si is essential primarily for diatoms that may increase food web and export efficiency via their large size and ballasting mineral shells, respectively. With a month-long mesocosm study in the subtropical North Atlantic, we tested the biological response to artificial upwelling with varying Si:N ratios (0.07-1.33). Community biomass increased 10-fold across all mesocosms, indicating that basic bloom dynamics were upheld despite the wide range in nutrient composition. Key properties of these blooms, however, were influenced by Si. Photosynthetic capacity and nutrient-use efficiency doubled from Si-poor to Si-rich upwelling, leading to C:N ratios as high as 17, well beyond Redfield. Si-rich upwelling also resulted in 6-fold higher diatom abundance and mineralized Si and a corresponding shift from smaller towards larger phytoplankton. The pronounced change in both plankton quantity (biomass) and quality (C:N ratio, size and mineral ballast) for trophic transfer and export underlines the pivotal role of Si in shaping the response of oligotrophic regions to upwelled nutrients. Our findings indicate a benefit of active Si management during artificial upwelling with the potential to optimize fisheries production and CO 2 removal.
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Multilateral crop trade is likely to drive enhancement or mitigation of nutrient surpluses of the trading countries; however, the driving mechanisms are unclear. Here we explore the effects of multilateral crop trade on nitrogen and phosphorus surpluses based on two optimal multilateral crop trade models, a regional nutrient surplus model and crop trade data. Focusing on China and Central Asia, we find that optimal multilateral crop trades are effective to mitigate both nutrient surplus and footprint. Compared to the base year (2018), a single-objective-based crop trade would drive an obvious transition from nitrogen surplus enhancement (1170.5 kt) to mitigation (−705.8 kt over 2030–2034); the phosphorus surplus enhancement would be transferred from 1741.5 to mitigation of −2934 kt. Driven by the bilevel-objective-based crop trade, great mitigations in both nitrogen and phosphorus surpluses are detected, with the projected levels reaching −571 and −2809 kt, respectively. This implies that strengthening optimal multilateral crop trades across the world would facilitate global nutrient management. Multilateral crop trading that maximizes the system benefit and minimizes the inequality level of water-land benefits could effectively mitigate both nutrient surplus and footprint, according to an integrated evaluation model for China and central Asia.
Regional scale simulation of crop yield is challenging due to the spatial variability of soil properties, crop varieties, management practices and weather conditions. Point-based crop models are commonly used for spatial simulation with increased availability of high-resolution spatial datasets. However, it is still difficult to calibrate crop models well due to the spatial variability of model inputs. The focus of this work was to determine if a single set of cultivar and soil parameters could be calibrated to simulate county level peanut yield and to evaluate the effects of irrigation to mitigate potential climate change impacts on peanut yield. Model input data for fourteen seasons and five major peanut producing counties was assembled and used for model calibration. Three seasons of data were withheld and used for an independent evaluation. Overall, peanut growth duration and county level yields were simulated well with a set of optimum cultivar and soil parameters for each county. The model calibration showed that simulated maturity dates and yields were in good agreement with the observed county level values reported by NASS, giving an overall R² of 0.71 and 0.73 and RMSE values of 6 days and 333 kg/ha, respectively. The model also generated good simulations of maturity dates and yield for the three evaluation seasons, with an overall R² of 0.83 and 0.76 and RMSE values of 5 days and 429 kg/ha, respectively. The results from future climate simulations indicated that the rainfed yields will suffer from increasing daytime temperature and an irrigation strategy could potentially offset the heat and water stress to maintain higher peanut production in the Southeastern USA. This study can enhance the accuracy of simulating the impact of climate change on crop production by providing a calibration and evaluation strategy that aggregates spatial heterogeneity of model inputs at the regional scale. Further research should test this method for other crops and more model applications, such as nitrogen leaching, groundwater use and fertilizer management.
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Drought and salinity stress severely inhibits the growth and productivity of crop plants by limiting their physiological processes. Silicon (Si) supplementation is considerd as one of the promising approaches to alleviate abiotic stresses such as drought and salinity. In the present study, a field experiment was conducted over two successive growth seasons (2019-20) to investigate the effect of foliar application of Si at two concentrations (1 and 2 kg Si ha-1) on the growth, yield and physiological parameters of three maize cultivars (ES81, ES83, and ES90) under three levels of irrigation salinity) [1000 (WS1), 2000 (WS2) and 3000 (WS3) mg L-1NaCl]. In this study, A trickle irrigation system was used. Si application significantly mitigated the harsh effects of salinity on growth and yield components of maize, which increased at all concentrations of Si. In irrigation with S3 salinity treatment, grain yield was decreased by 32.53%, however, this reduction was alleviated (36.19%) with the exogenous foliar application of Si at 2 kg Si ha-1. At salinity levels, Si application significantly increased maize grain yield (t ha-1) to its maximum level under WS of 1000 mg L-1, and its minimum level (Add value) under WS of 3000 mg L-1. Accordingly, the highest grain yield increased under Si application of 2 kg Si ha-1, regardless of salinity level and the cultivar ES81 achieved the highest level of tolerance against water salinity treatments. In conclusion, Application of Si at 2 kg Si ha-1 as foliar treatment worked best as a supplement for alleviating the adverse impacts of irrigation water salinity on the growth, physiological and yield parameters of maize.
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Industrial sector emissions of greenhouse gases (GHGs) include carbon dioxide (CO2) from energy use, from non-energy uses of fossil fuels and from non-fossil fuel sources (e.g., cement manufacture); as well as non-CO2 gases. Energy-related CO2 emissions (including emissions from electricity use) from the industrial sector grew from 6.0 GtCO2 (1.6 GtC) in 1971 to 9.9 GtCO2 (2.7 GtC) in 2004. Direct CO2 emissions totalled 5.1 Gt (1.4 GtC), the balance being indirect emissions associated with the generation of electricity and other energy carriers. However, since energy use in other sectors grew faster, the industrial sector’s share of global primary energy use declined from 40% in 1971 to 37% in 2004. In 2004, developed nations accounted for 35%; transition economies 11%; and developing nations 53% of industrial sector energy-related CO2 emissions. CO2 emissions from non-energy uses of fossil fuels and from non-fossil fuel sources were estimated at 1.7 Gt (0.46 GtC) in 2000. Non-CO2 GHGs include: HFC-23 from HCFC-22 manufacture, PFCs from aluminium smelting and semiconductor processing, SF6 from use in electrical switchgear and magnesium processing and CH4 and N2O from the chemical and food industries. Total emissions from these sources (excluding the food industry, due to lack of data) decreased from 470 MtCO2-eq (130 MtC-eq) in 1990 to 430 MtCO2-eq (120 MtC-eq) in 2000. Direct GHG emissions from the industrial sector are currently about 7.2 GtCO2-eq (2.0 GtC-eq), and total emissions, including indirect emissions, are about 12 GtCO2-eq (3.3 GtC-eq) (high agreement, much evidence). Approximately 85% of the industrial sector’s energy use in 2004 was in the energy-intensive industries: iron and steel, non-ferrous metals, chemicals and fertilizers, petroleum refining, minerals (cement, lime, glass and ceramics) and pulp and paper. In 2003, developing countries accounted for 42% of iron and steel production, 57% of nitrogen fertilizer production, 78% of cement manufacture and about 50% of primary aluminium production. Many industrial facilities in developing nations are new and include the latest technology with the lowest specific energy use. However, many older, inefficient facilities remain in both industrialized and developing countries. In developing countries, there continues to be a huge demand for technology transfer to upgrade industrial facilities to improve energy efficiency and reduce emissions (high agreement, much evidence). Many options exist for mitigating GHG emissions from the industrial sector (high agreement, much evidence). These options can be divided into three categories: Sector-wide options, for example more efficient electric motors and motor-driven systems; high efficiency boilers and process heaters; fuel switching, including the use of waste materials; and recycling. Process-specific options, for example the use of the bio-energy contained in food and pulp and paper industry wastes, turbines to recover the energy contained in pressurized blast furnace gas, and control strategies to minimize PFC emissions from aluminium manufacture. Operating procedures, for example control of steam and compressed air leaks, reduction of air leaks into furnaces, optimum use of insulation, and optimization of equipment size to ensure high capacity utilization. Mitigation potential and cost in 2030 have been estimated through an industry-by-industry assessment for energy-intensive industries and an overall assessment for other industries. The approach yielded mitigation potentials at a cost of <100 US$/tCO2-eq (<370 US$/tC-eq) of 2.0 to 5.1 GtCO2-eq/yr (0.6 to 1.4 GtC-eq/yr) under the B2 scenario[1]. The largest mitigation potentials are located in the steel, cement, and pulp and paper industries and in the control of non-CO2 gases. Much of the potential is available at <50 US$/tCO2-eq (<180 US$/tC-eq). Application of carbon capture and storage (CCS) technology offers a large additional potential, albeit at higher cost (medium agreement, medium evidence). Key uncertainties in the projection of mitigation potential and cost in 2030 are the rate of technology development and diffusion, the cost of future technology, future energy and carbon prices, the level of industry activity in 2030, and climate and non-climate policy drivers. Key gaps in knowledge are the base case energy intensity for specific industries, especially in economies-in-transition, and consumer preferences. Full use of available mitigation options is not being made in either industrialized or developing nations. In many areas of the world, GHG mitigation is not demanded by either the market or government regulations. In these areas, companies will invest in GHG mitigation if other factors provide a return on their investment. This return can be economic, for example energy efficiency projects that provide an economic payout, or it can be in terms of achieving larger corporate goals, for example a commitment to sustainable development. The slow rate of capital stock turnover is also a barrier in many industries, as is the lack of the financial and technical resources needed to implement mitigation options, and limitations in the ability of industrial firms to access and absorb technological information about available options (high agreement, much evidence). Industry GHG investment decisions, many of which have long-term consequences, will continue to be driven by consumer preferences, costs, competitiveness and government regulation. A policy environment that encourages the implementation of existing and new mitigation technologies could lead to lower GHG emissions. Policy portfolios that reduce the barriers to the adoption of cost-effective, low-GHG-emission technology can be effective (medium agreement, medium evidence). Achieving sustainable development will require the implementation of cleaner production processes without compromising employment potential. Large companies have greater resources, and usually more incentives, to factor environmental and social considerations into their operations than small and medium enterprises (SMEs), but SMEs provide the bulk of employment and manufacturing capacity in many developing countries. Integrating SME development strategy into the broader national strategies for development is consistent with sustainable development objectives (high agreement, much evidence). Industry is vulnerable to the impacts of climate change, particularly to the impacts of extreme weather. Companies can adapt to these potential impacts by designing facilities that are resistant to projected changes in weather and climate, relocating plants to less vulnerable locations, and diversifying raw material sources, especially agricultural or forestry inputs. Industry is also vulnerable to the impacts of changes in consumer preference and government regulation in response to the threat of climate change. Companies can respond to these by mitigating their own emissions and developing lower-emission products (high agreement, much evidence). While existing technologies can significantly reduce industrial GHG emissions, new and lower-cost technologies will be needed to meet long-term mitigation objectives. Examples of new technologies include: development of an inert electrode to eliminate process emissions from aluminium manufacture; use of carbon capture and storage in the ammonia, cement and steel industries; and use of hydrogen to reduce iron and non-ferrous metal ores (medium agreement, medium evidence). Both the public and the private sectors have important roles in the development of low-GHG-emission technologies that will be needed to meet long-term mitigation objectives. Governments are often more willing than companies to fund the higher risk, earlier stages of the R&D process, while companies should assume the risks associated with actual commercialisation. The Kyoto Protocol’s Clean Development Mechanism (CDM) and Joint Implementation (JI), and a variety of bilateral and multilateral programmes, have the deployment, transfer and diffusion of mitigation technology as one of their goals (high agreement, much evidence). Voluntary agreements between industry and government to reduce energy use and GHG emissions have been used since the early 1990s. Well-designed agreements, which set realistic targets, include sufficient government support, often as part of a larger environmental policy package, and include a real threat of increased government regulation or energy/GHG taxes if targets are not achieved, can provide more than business-as-usual energy savings or emission reductions. Some voluntary actions by industry, which involve commitments by individual companies or groups of companies, have achieved substantial emission reductions. Both voluntary agreements and actions also serve to change attitudes, increase awareness, lower barriers to innovation and technology adoption, and facilitate co-operation with stakeholders (medium agreement, much evidence).
The food crisis could have dire effects on the poor. Politicians have it in their power to bring food prices down. But doing so will require ending the bias against big commercial farms and genetically modified crops and doing away with damaging subsidies-the giants of romantic populism, bolstered by both illusion and greed.