Disintegrating the impact of climate change on maize yield from human management practices in China

Climate warming has posed one of the greatest threats to global food security during the 21st century. Evidence suggests that such a threat could be partly offset by promoting food production through human management. Most studies have focused on quantifying the impact of climatic factors on food quantity. However, the contributions of human management practices, including fertilization and irrigation, to food production are yet to be comprehensively understood. Using integrated information on climate, fertilizer use, and irrigation water allocation across China's 208 prefecture-level administrative divisions, as well as four spatial panel models, we have successfully disintegrated the relative effects of climate change and human management practices on China's maize yield. From 1982 to 2013, the average maize yield in maize planting regions in China increased by 1.7 times. The overall impact of human management (fertilizer use and irrigation) on maize yield was higher than that of climate change (based on the optimal spatial Durbin model where the coefficients of most factors were significant at p < 0.01; R-2 = 0.65). The vapor pressure deficit (VPD) was the main influencing factor on maize yield followed by nitrogen and phosphorus (N&P) fertilizer use, precipitation, and diurnal temperature range (DTR) respectively. For example, maize yield would decrease by 15.0% per 0.1 kPa increase in VPD and increase by 29% per 10 g added in N&P fertilizer per square meter. Specifically, the VPD negatively influenced the maize yield in the Northern spring and the Southwest maize region, while the increased temperature negatively influenced the maize yield in the Huang-Huai spring-summer maize region. The N&P fertilizer use, precipitation, and diurnal temperature range all positively influenced the maize yield. N&P fertilizer use in the South maize region had a greater effect on improving maize yield than the other regions. The yield in the South maize region benefited more from human activities. This research could provide a timely reference for improving food production in China's maize planting regions and maintaining food security.