The Impact of Heavy Rainfall Variability on Fertilizer Application Rates: Evidence from Maize Farmers in China.

Global warming increases the intensity and frequency of extreme weather events, which is harmful to agricultural production. Given that the overuse of fertilizer has been found to be a significant contributor to global warming, it is crucial to analyze the factors affecting farmers' fertilizer use and find appropriate fertilizer reduction measures. Agriculture is inherently risky, but previous studies have ignored the risk factors related to heavy rainfall variability, including fertilizer losses and the possible yield risks, which may lead to income risk. Using the 1995-2018 National Rural Fixed Observation Point Survey Data, this study examines the impact of heavy rainfall variability on maize farmers' fertilizer application rates, aiming to understand farmers' fertilization behavior in response to weather shocks. The results show that heavy rainfall variability significantly increases farmers' fertilizer application rates on maize. Furthermore, we find that heavy rainfall variability has greater effects on fertilizer use in hills and mountainous areas and areas with good irrigation conditions or high economic levels. When examining the potential channels underlying the estimated effects, we find that yield fluctuations are a channel through which heavy rainfall variability affects farmers' fertilizer use on maize. The above results indicate that farmers view applying extra fertilizer as a risk reducing activity in response to rainfall shocks, which helps to prevent low yield and income. Strengthening agricultural infrastructure construction according to local conditions and promoting fertilizer reduction technologies and products to reduce yield risk caused by heavy rainfall can help alleviate the problem of high fertilizer application rates by Chinese farmers.