Long-term reduction of nitrogen fertilizer use through knowledge training in rice production in China

•One time training is not effective in reducing farmers' N-fertilizer use in the long run.•Reducing excessive use of N-fertilizer in the long term requires intensive training.•Intensive training requires substantial investment and institutional innovation. Nitrogen (N) fertilizer has been excessively used in China's crop production, resulting in nonpoint pollution and significant greenhouse gas emissions. Previous studies show that farmers can reduce N-fertilizer upon receiving knowledge training. However, there is little evidence of the effectiveness of this effort in the long term. Based on an experimental study of site-specific nutrient management for rice production in China and a unique household dataset captured over seven years, this study shows that the traditional training approach has not been effective in reducing Chinese farmers' N-fertilizer use. Persistently reducing farmers' excessive use of N-fertilizer in the long term will require intensive in-field guidance – something that requires substantial investment and institutional innovation.