Heterogeneous effects of information provision on fertilizer use in China's rice production

The inappropriate use, especially overuse, of fertilizers aggravates greenhouse gas emissions and non-point source pollution. China is the largest fertilizer user worldwide, and information provision is a determinant of farmers' fertilizer use. Using survey data of 1002 rice farmers from Hubei, Jiangsu and Jiangxi provinces in China, this study aims to analyze the heterogeneity in farmers' fertilizer use and evaluate the heterogeneous effects of various modes of information provision on fertilizer use among different groups of farmers. A group of extended difference-in-differences models are developed and estimated based on a two-year randomized controlled trial. Results show that while farmers as a whole overuse fertilizers, there is copresence of overusers, consistent users and underusers. Information provision induces a sizeable fertilizer reduction among the overusers and a moderate increase among the underusers. Moreover, the reduction is small among top overusers. Information provision by public agricultural extension agents exerts larger reduction effects among the overusers than that by fertilizer firms, while that by fertilizer firms exerts larger incremental effects among the underusers. These findings illustrate that information provision is effective in rationalizing farmers' fertilizer use in China and underscores the importance of reinforcing such a mechanism. This study provides fresh evidence for the copresence of fertilizer overuse and underuse in China and might be the first to investigate the heterogeneous effects of various modes of information provision on fertilizer use among the overusers, consistent users and underusers of fertilizers, which has crucial policy implications for rationalizing fertilizer use in China.