The use of nitrogen (N) and other fertilisers has been one of the keys to achieving food security in China. Grain production almost doubled in China between 1980 and 2010, yet total fertiliser use increased more than four-fold in the same period. This disparity is partly due to changes in cropping, with a large increase in the area devoted to horticultural crops (vegetables and fruit trees) that are given large rates of fertiliser, especially N. But it also reflects the extremely high rates of N application given to a wide range of crops, including cereals. There is overwhelming evidence that rates of N applied to many crops in many regions of China are greatly in excess of the rates required to achieve maximum economic yield. These excessively high rates, combined with inappropriate fertiliser management practices such as timing and method of application, have led to very inefficient use of N and considerable losses to water and air with numerous adverse environmental impacts. A key reason for much of the inappropriate fertiliser management is that many farmers are part-time, with more lucrative income from off-farm work. Thus farm operations are given a low priority, with little incentive to change practices if these involve additional costs, or labour, that interferes with the off-farm work. In this article we review the current situation regarding N fertiliser in China, with an emphasis on the reductions in greenhouse gas emissions that are achievable through changes in both manufacturing and agricultural use. We argue that, although technical innovations have a role, these are only likely to be widely adopted in practice if policy changes are implemented to promote changes in fertiliser manufacturing and on the farm. Necessary changes in policy include changes to the subsidy, originally developed to make fertilisers affordable to farmers in the period before rapid economic development in the country. At the farm level, policies to promote greater professionalism in farming through increasing the size of farms will facilitate more rational use of N. This is possible as large numbers of former farmers move to other work in cities; the Chinese government has policy initiatives in this area through changes in land rental arrangements. Another welcome change would be measures to promote more farmer-oriented approaches to the delivery of technical advice such as the farmer field-school approach, and development of a contractor sector for fertiliser application.
|Publication status||Published - 21 Oct 2014|