NEWS | 07 MARCH 2018
Millions of Chinese farmers reap benefits of huge crop experiment
Decade-long study involving 21 million smallholders shows how evidence-based approaches could improve food security.
David Cyranoski
Rice farmers in China increased their crop yields when they adopted new evidence-based farming practices.Credit: KeystoneUSA-ZUMA/REX/Shutterstock
A landmark project to make agriculture more sustainable in China has significantly cut fertilizer use while boosting crop yields on millions of small farms across the country, researchers report in
Nature1.
As part of a decade-long study, scientists analysed vast amounts of agricultural data to develop improved practices, which they then passed on to smallholders. Through a national campaign, about 20.9 million farmers adopted the recommendations, which increased productivity and reduced environmental impacts. As a result of the intervention, farmers were together US$12.2 billion better off.
The scale of the project has stunned international scientists. With the global demand for food expected to double between 2005 and 2050, they hope that the study’s lessons can be applied to other countries. “This is an astonishing project of a scale way beyond anything I am familiar with,” says Leslie Firbank, who studies sustainable intensification of agriculture at the University of Leeds, UK.
Charles Godfray, a population biologist at the University of Oxford, UK, says that, over the past 30 years, China has achieved an agricultural miracle by producing enough food to feed the vast majority of its 1.4 billion people. But this feat has come at a tremendous cost to the environment, he says. Fertilizers, such as nitrogen, have increased crop production but have also acidified soil, polluted water and contributed to global warming. Godfray says the latest study demonstrates that it is possible to reduce fertilizer use while increasing economic returns on a large scale.
Tailored advice
Chinese farmers use about 305 kilograms of nitrogen per hectare a year, which is more than four times the global average. Project leader Cui Zhenling at the China Agricultural University in Beijing and his collaborators took up the challenge to cut that use without lessening farmers’ yields.
From 2005 to 2015, the project team conducted 13,123 field studies at maize (corn), rice and wheat farms across the country, from the subtropical south to the frigid north. The researchers tested how yields varied with different crop varieties, planting times, planting densities, fertilizer and water use. They also measured sunlight and the effect of the climate on farm production.
Source: Z. Cui et al. Nature http://dx.doi.org/10.1038/nature25785 (2018)
With data from the field trials, Cui and his colleagues developed evidence-based advice that was given to farmers on the basis of their local conditions. For example, the team recommended that rice farmers in northeast China reduce their overall nitrogen use by 20% on average, while increasing the nitrogen applied late in the growing season and planting the seeds closer together.
Almost 21 million farmers adopted the group’s recommendations between 2006 and 2015. In that period, crop production for each grain increased by an average of around 11%. The study’s collaborators also recorded a surprising drop in fertilizer use — about 15% per crop — saving 1.2 million tonnes of nitrogen. “The demonstration that reducing inputs can actually boost agricultural, environmental and economic performance at scale is very important,” says Godfray.
Management success
A combination of outreach programmes and workshops — about 14,000 over 10 years — helped to convince the farmers to adopt the recommendations. “The [farmers] were sceptical, but we gained their trust, and then they depended on us — that was our greatest reward,” says Cui. The project, which also provided on-site demonstrations and high-quality seeds and fertilizers at some sites, cost around $54 million.
To enrol and educate the farmers, more than 1,000 researchers across China worked with 65,000 bureaucrats and technicians at provincial or county agricultural agencies and with 140,000 representatives from agriculture businesses. The project’s success highlights the importance of the vast social networks, says Jules Pretty, who researches the environment and society at the University of Essex in Colchester, UK.
David Tilman, an ecologist at the University of Minnesota in St Paul, says the study is a rare example of scientific knowledge being properly implemented in farming. “The greatest barrier to sustainable agricultural is getting farmers to adopt more efficient practices,” he says, adding that the project offers a path for other nations to follow.
But some researchers think the project’s lessons may be difficult to translate to other regions. China’s improved yields resulted from reducing fertilizer overuse, but many farmers in low- and middle-income countries don’t have access to enough fertilizer, says Godfray. He says that China’s centrally controlled government is uniquely capable of implementing policies across the country, which is not the case in other regions. “It would clearly have benefits across sub-Saharan Africa, but an approach is needed that crosses borders, organizations and funders,” says Firbank.
These challenges shouldn’t stop other countries from trialling a similar experiment, says Tilman, but improving farm productivity is not enough. “The China study proves that nations do not have to pollute lakes, rivers and the ocean in order to feed themselves,” he says. “A great remaining challenge that all nations face is adopting healthier, low-meat diets that prevent disease and preserve the environment.”
Millions of Chinese farmers reap benefits of huge crop experiment | Nature
Zhenling Cui, Hongyan Zhang, Xinping Chen, Chaochun Zhang, Wenqi Ma, Chengdong Huang, Weifeng Zhang, Guohua Mi, Yuxin Miao, Xiaolin Li, Qiang Gao, Jianchang Yang, Zhaohui Wang, Youliang Ye, Shiwei Guo, Jianwei Lu, Jianliang Huang, Shihua Lv, Yixiang Sun, Yuanying Liu, Xianlong Peng, Jun Ren, Shiqing Li, Xiping Deng, Xiaojun Shi, Qiang Zhang, Zhiping Yang, Li Tang, Changzhou Wei, Liangliang Jia, Jiwang Zhang, Mingrong He, Yanan Tong, Qiyuan Tang, Xuhua Zhong, Zhaohui Liu, Ning Cao, Changlin Kou, Hao Ying, Yulong Yin, Xiaoqiang Jiao, Qingsong Zhang, Mingsheng Fan, Rongfeng Jiang, Fusuo Zhang & Zhengxia Dou.
Pursuing sustainable productivity with millions of smallholder farmers,
Nature (2018).
DOI: 10.1038/nature25785
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EDITORIAL | 07 MARCH 2018
Chinese project offers a brighter farming future
A massive, decade-long experiment involving millions of Chinese farmers demonstrates an evidence-based approach to sustainability.
A giant experiment with 21 million farmers in China points the way to sustainable agriculture.Credit: Feng Xiaomin/Xinhua/eyevine
In 1958, China under Mao Zedong embarked on a nationwide political project to increase agricultural productivity by collectivizing small farms across the country and forcing them to share agricultural tools. It was a disaster and contributed to a famine in which tens of millions died.
Now science has succeeded where ideology failed. A huge, decade-long experiment involving millions of farmers reports its results this week. Writing in
Nature, scientists in China describe how they identified and passed on evidence-based techniques to make smallholder farming in the country more efficient (
Z. Cui et al. Naturehttp://dx.doi.org/10.1038/nature25785; 2018). No sharing of agricultural tools was required; just the gathering and pooling of scientific data on local conditions and agricultural needs.
Running from 2005 to 2015, the project first assessed how factors including irrigation, plant density and sowing depth affected agricultural productivity. It used the information to guide and spread best practice across several regions: for example, recommending that rice in southern China be sown in 20 holes densely packed in a square metre, rather than the much lower densities farmers were accustomed to using.
The results speak for themselves: maize (corn), rice and wheat output grew by some 11% over that decade, whereas the use of damaging and expensive fertilizers decreased by between 15% and 18%, depending on the crop. Farmers spent less money on their land and earned more from it — and they continue to do so.
The results offer hope in the search for a more sustainable future on a crowded planet. After all, some 2.5 billion smallholders together farm 60% of the world’s arable land. Beyond that, the project provides many lessons. First, that a scientific approach can increase agricultural productivity and cut damage to the environment. Second, that such success requires investment in what economists call the intangibles — the creation of networks to spread information and give scientists access to essential data. The scale of the research network created is impressive: 1,200 scientists, 65,000 local officials, 140,000 industry representatives and 21 million farmers across 37.7 million hectares.
Maintaining the people in those networks — in this case, the technicians and bureaucrats in local government offices — is a must. The study shows how these posts can produce benefit, both economic and environmental, far beyond what they cost. Unfortunately, in many countries, such jobs and the networks that depend on them are being cut back, often, paradoxically, in the name of efficiency.
The third lesson is that the same methods could, in principle, be used to boost agricultural efficiency elsewhere. But that will not be easy. China has well-developed regional infrastructure and relatively efficient central control, both of which allowed this project to operate on such a large scale. India and Africa — two regions that could benefit from a similar approach — do not. That makes it difficult, although not impossible, to translate the study and the results beyond China.
Fourth, the programme must be monitored and updated. Its recommendations were fine-tuned to the needs of farmers in specific regions, but these can change, especially as the climate alters. To consolidate their success, the farmers and scientists involved should continue to adapt the recommended methods.
China must now build on this project. Some 200 million smallholdings are not yet plugged into the information networks set up and so are not applying the recommendations. There is scope for easy wins here. For example, researchers could piggyback on existing but separate networks. One is the Science and Technology Backyard platforms, which operate in 21 provinces and cover a wide range of crops. They bring agricultural scientists to live in villages, and use demonstrations to show farmers better techniques. Such projects could ensure that farmers continue to learn. They could also be expanded to investigate the best use of other agricultural options, such as pest management and the use of legumes as alternatives to fertilizers.
Perhaps the most important lesson is that better use of existing technology can help to produce more food in a sustainable way. None of the recommendations given to China’s farmers would have surprised agronomists. Still, the scientists involved deserve great credit for having the vision and the wherewithal to make the project happen.
There is a thrill in finding that expectations hold up over so grand a scale. And, ultimately, it was that scale that made the difference. It allowed the project to go where even the best smaller studies (and Mao Zedong) could not: persuading often intractable rural farmers to change their practices, and so improve efficiency and productivity.
Nature 555, 141 (2018)
doi: 10.1038/d41586-018-02742-3
Chinese project offers a brighter farming future | Nature
