SCIENCE

Moderately expanding the scale of agricultural operations will help reduce the “fat” of cultivated land


Fertilizers and pesticides are one of the hallmarks of modern agriculture, which guarantees the yield and quality of human food, but its excessive use also brings a series of ecological and environmental problems. In China, the problem is particularly acute. A new study by an interdisciplinary team from Zhejiang University found that the scale of agricultural operations is an important factor affecting the amount of agrochemicals applied. Moderately expanding the scale of agricultural operations can effectively help reduce the “fat” of cultivated land. The paper was published online in the June 18 issue of the journal PNAS (Proceedings of the National Academy of Sciences).

The reporter learned that the reviewer of the paper, distinguished professor of Michigan State University, and the Department of Plant Soil and Microbial Sciences, G. Dr. Philip Robertson argues that this study provides important insights into the sustainable development of agriculture in China and conducts rigorous and convincing empirical tests.

Associate Researcher Wu Yiyun of Zhejiang University and Dr. Xi Xican of Fudan University are the co-first authors of the paper, and Gu Baojing, researcher of Zhejiang University, and Professor Peter Vitousek of Stanford University are the co-corresponding authors of the paper. The research was led by Zhejiang University and jointly completed by teams from Fudan University, Wuhan University, Stanford University and the University of Melbourne.

It is understood that China uses 60 million tons of chemical fertilizers and 1.8 million tons of pesticides every year – 1/3 of the world’s agrochemicals are consumed on 9% of the cultivated land, “the fertilizer crops applied are only used less than half”, said Gu Baojing, a researcher with a professional background in the ecological environment, “The rest mainly enters the water body and the atmosphere, causing serious pollution to the environment.” ”

Three years ago, Wu Yiyun and Gu Baojing jointly paid attention to this dilemma, so what factors are influencing farmers’ decision-making behavior? They need access to large-scale microdata to support our research.

The China Rural Household Survey Database, which Zhejiang University is building, provides a nationally representative basic data support for this research. The database organizes a national rural household survey every two years, comprehensively records the development of China’s rural society, economy, politics, culture, resources and environment, and can help scholars explain and predict the development and changes of China’s rural society from the perspective of causation.

The research team retrieved the data of more than 20,000 rural households in the database and made a major discovery: after controlling other factors, the scale of agricultural operations is a powerful factor affecting the intensity of the use of agricultural chemicals on Chinese farms. According to the results of statistical analysis, for every 1% increase in the average arable land area per household, the amount of fertilizer and pesticide application per hectare decreased by 0.3% and 0.5%, respectively. Through collaboration with Fudan University, Wuhan University, Stanford University and the University of Melbourne, the research team expanded its horizons to the changing trend of farmland scale and agrochemical application intensity in 74 countries from the 1960s to the present, and found that the research conclusions were highly general.

So how big is the scale of agricultural operations moderate? “At present, this tipping point is about 18 acres”, but this critical point will continue to grow with the economic development of our country until a new equilibrium point is reached.

Equilibrium point of agricultural land size (2015 data)

“At present, the average cultivated land area in rural Areas in China is 6-8 mu.” Gu Baojing said, “This study inspires us that if there is a more complete agricultural land circulation market and a more complete social security mechanism, the phenomenon of small-scale farmers dominating will be improved.” ”

Wu Yiyun believes that China’s gradual promotion of moderate-scale agricultural operation and household registration system reform in recent years will promote the reduction of “fat” on cultivated land to a certain extent. “This is a very key motivation, and from our research, only when the area of arable land increases, farmers will really have the willingness to accept new technologies.” Gu Baojing said.

The problem of land being “fattened” is not an isolated case in China. Now, Gu Baojing can take his research paper and then discuss their research findings with foreign professors, because this discovery is also applicable to other developing countries outside China, and in order to reduce the “fertilizer” of arable land, it may be an effective way to gradually expand the scale of farmland through corresponding policy support, which will provide development experience for late-developing countries to avoid from insufficient chemical fertilizer application to excessive chemical fertilizer application.



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