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Strengthening Agronomy Research for Food Security and Environmental Quality Zhenling Cui,† Peter M. Vitousek,‡ Fusuo Zhang,† and Xinping Chen*,† †
Key Laboratory of Plant-Soil Interactions, Ministry of Education, Center for Resources, Environment and Food Security, China Agricultural University, Beijing 100193, China ‡ Department of Biology, Stanford University, Stanford, California 94305, United States Recent agricultural research in developed countries has focused upon agricultural biotechnology, much of it in the private sector. This approach has contributed to the high yield ceiling in U.S. maize (Figure, 1A); here the yield ceiling is defined as yields achieved under optimum management in wellcontrolled experimental systems). China too has supported crop breeding, including a recent focus on newer methods in biotechnology. The similarity in maize yield ceiling between the U.S. and China illustrates the long-term success of this approach. Maize cropping systems in the U.S. have a relatively narrow yield gap (the difference between yield ceiling and the actual yield achieved by farmers),2 contributing to their high overall yields (Figure 1B). The yield gap in China is much larger (Figure 1C), and increased agronomic inputs cannot close this gap, because China already has gone past a point of diminishing returns in the case of fertilizer applications in particular (Figure 1D,E). Chinese systems now yield only 35 kg of grain per kg of N (versus 67 kg kg−1 in the U.S.); they lose much more N to the environment, with substantial and growing environmental costs (621 versus 231 kg CO2 eq per Mg grain for China and U.S., respectively) (Figure 1F). griculture faces great challenges to ensure global food Can China and other rapidly developing countries increase security by increasing yields while reducing environmental yields (as they must) by following paths similar to the U.S. and Europe? U.S. agriculture has benefited from relatively high, costs.1 This linked production/environment challenge is long-term agricultural research and development (R&D) particularly stark in rapidly developing economies, such as investment. Agricultural R&D intensities have long remained China and India; it is here that the potential yields of >2%, expressed as the percentage of agriculture R&D spending agriculture must be raised close to their biophysical potential, (public and private) to agricultural gross domestic product.3 In here that gaps between potential and realized yields must be the past this investment supported basic agronomy research on minimized, and here that already-intolerable levels of environregional scales - including crop physiology, soil biogeochemmental degradation must be reduced. China has 124 million ha istry, and integrated crop-soil management−in addition to crop of farmland with which to feed over 1.37 billion people (versus biotechnology. This investment has led to crops resistant to 165 million ha and 311 million people in the U.S.), and its air various biotic and abiotic stresses, which become more serious and water are so polluted by industry and agriculture that China under changing climate, managed with high-technology now experiences 750 000 premature pollution-caused deaths precision agriculture. In turn these developments, together per year. Increasing crop yields toward limits of feasibility while with large-scale farms and well educated farmers, drive the at the same time saving many lives represents an immediate, narrow yield gaps and relatively efficient nutrient use compelling scientific challenge as well as an extraordinary characteristic of US agriculture.3 contribution to human well-being. In contrast to the U.S., agriculture in China and India is Possible solutions to global agricultural challenges have been managed by more than one hundred million small-holder discussed widely in the scientific community; they include crop farmers, often with low levels of education - a situation that breeding through biotechnology and high-technology precision contributes to substantial variation in both crop yield and fertilizer use among farmers. Under these circumstances, many agriculture−which together have made substantial contribupromising crop varieties fail to increase yields in practice. For tions to the high-yielding and relatively resource-efficient cropping systems of North America and Western Europe. Can these relatively efficient agricultural systems provide a path Received: January 18, 2016 toward similar successes in rapidly developing economies?
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© XXXX American Chemical Society
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DOI: 10.1021/acs.est.6b00267 Environ. Sci. Technol. XXXX, XXX, XXX−XXX
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Environmental Science & Technology
Figure 1. Yield ceiling (A), current yield (B), yield gap (C), N application rate (D), yield per unit fertilizer N applied (E), and GHG emission intensity (F) for maize cropping systems in China and the U.S. The GHG emission included CO2, CH4, and N2O during the whole life cycle of crop production.
agronomic research provides benefits to both farmers and society in the form of greater yields and cleaner water, better soil quality, reduced greenhouse gas emissions, and enhanced biological diversity. These investments should receive the strongest support from governments and nongovernmental organizations.
example, a recent increase in maize yield ceiling provided by crop breeding had no detectable effect on actual regional and national scale maize yields.4 These failures were due to inadequate regional strategies for making use of these varieties within integrated systems of soil-crop management. Similarly, precision agriculture approaches used in large-scale farms in the US are not applicable either technically or economically on the small farms of China and India. However, simple, regionally specific agronomic strategies based on knowledge of soil, crop, climate, and their interactions on regional scales can be developed and implemented, and these strategies can provide most of the production and environmental benefits of precision agriculture at a fraction of the technology and costs.4 Agricultural systems in China and elsewhere will change as rural labor becomes scarcer and more expensive, and both yields and environmental quality must continue to improve throughout these changes. Increasing yields while reducing environmental damages in the face of social and economic change requires investment−but unfortunately China’s agricultural R&D intensity has been low for some decades. It was less than 0.4% in 2000 (India was the same), much lower than the 2.36% for developed economies.3 Recently, China has significantly increased her investment in agriculture research (to 0.77% in 2009),5 but more will be required to offset decades of under-investment. Overall, we suggest that investing in a broad spectrum of research and development, in agronomy and outreach as well as in biotechnology shows great promise for increasing crop yields and improving the resource efficiency of agriculture, while greatly reducing harm to the environment. Such research can be beneficial anywhere, but its payoff is likely to be particularly high in rapidly developing economies. Investments in genetics will remain highly productive, and much of this investment can come from the private sector because of the opportunities for property rights and profits. However, there are fewer opportunities for private profit from agronomic research designed to improve soil and crop management. Such
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AUTHOR INFORMATION
Corresponding Author
*Phone: 0086-10-62733454; fax: 0086-10-62731016; e-mail:
[email protected]. Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS The current work is funded the Chinese National Basic Research Program (2015CB150400), the National Maize Production System in China (CARS-02-24), National Natural Science Foundation--Outstanding Youth Foundation (31522050), and the Innovative Group Grant from NSFC (31421092).
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DOI: 10.1021/acs.est.6b00267 Environ. Sci. Technol. XXXX, XXX, XXX−XXX
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DOI: 10.1021/acs.est.6b00267 Environ. Sci. Technol. XXXX, XXX, XXX−XXX
