Improved economic and environmental outcomes from targeted fertilizer policy.

The overuse of nitrogen (N) fertilizer for wheat is a serious problem in China, and previous studies seldom distinguish between the use of basal and topdressing N fertilizer. Data from 225 households in Jiangsu Province, China (a wheat planting area), were collected through face-to-face interviews with each head of the household. Regression models were used to study factors affecting farmers' application of basal and topdressing N fertilizers separately. Fertilizer retailers proposed fertilizer application levels that were in opposition to their concern for the environment. Farmers' concern for the environment only affected their application of topdressing N fertilizer and had no significant influence for use of total N fertilizer. The farmland area and amount of experience planting wheat had negative effects on basal N fertilizer use, but not on topdressing fertilizer. In the study area, the optimal strategy for decreasing N fertilizer application is designing policies to rent more farmlands to farmers with the most experience first. These farmers with their higher farm income would decrease basal N fertilizer use and the basal-topdressing ratio to improve N fertilizer use efficiency and then decrease the N fertilizer leaching into the environment.