Which policy is preferred by crop farmers when replacing synthetic fertilizers by manure? A choice experiment in China

Replacing synthetic fertilizers by livestock manure has agronomic and environmental benefits, especially for countries with increasing livestock population and large fertilizer use, e.g. China. However, there are various socioeconomic and technical barriers for replacing fertilizers by manure, which are not well-understood. Consequently, recent governmental action programs are not well-targeted to the needs of crop farmers, and thus not effective. This study investigated farmers’ preferences for technical and financial incentives for using manure, through a farm survey with choice experiment among 1400 crop farmers across China. Farmers preferred a policy package, including field guidance, machinery service and financial support. The preferred package will increase the proportion of manure N in total N input (fertilizers + manures) from zero to 6–11% on farms that used no manure so far, while had little influence on current manure users (<4%). We estimated that this package will double the amounts of manure recycled in cropland, reducing total fertilizer N use by 16.5%, equivalent to 7.2 Tg N in 2019. Especially crop farmers with a relatively high income, large farmland area, and high level of education were willing to apply manure. We conclude that enhanced replacement of fertilizer N by manure requires a package of technical services, financial support, and machinery services for cereal farmers, while field demonstrations and manure application machines were prioritized by cash crop farmers. These packages will greatly increase nutrient use efficiency and reduce the environmental burdens caused by poor manure disposal practices and large fertilizer use.