Impact of Climatic Factors and Nitrogen Levels Drivers on Crop Yield in the Arid Region of China

Crop production depends on the interaction of climatic factors and agricultural management, such as nitrogen (N) fertilizer input in agricultural ecosystems. Understanding crop yield responses to climatic factors and N fertilizer supply can help select appropriate cultivars and develop appropriate measures to achieve the high and stable crop yield. In this study, a long-term N fertilizer experiment was conducted consisting of two crops (winter wheat and summer maize) from 1992 to 2014, to investigate the crop yield response to climatic factors and N treatments in Hotan, Xinjiang Uygur autonomous region. A long-term N supplied and without N supplied treatments significantly affect the soil properties and crop yields. It was found that low N stress significantly reduced the grain yield ranged from 33.1 to 76.4% and 26.8 to 69.3% for winter wheat and summer maize respectively. The grain N concentration was significantly reduced with the increase in N stress. There was positive correlation between crop yield and accumulated temperature (R2 = 0.58, P < 0.001) under high N conditions, and negative correlation (R2 = 0.50, P < 0.001) under low N conditions. Our result shows that the accumulated temperature is gradually increasing from 4051 to 5218 °C year−1 in the past 23 years (1992–2014) in Xinjiang Uygur autonomous region. Under sufficient N supplied conditions, the increase of accumulated temperature positively promote crop yields. However, under N deficient conditions, increasing accumulated temperature will further exacerbate the N stress effect and reduce crop yields. Hence, we recommended sufficient N fertilizer input in Hotan, Xinjiang region, which can maintain higher crop yield.