Quantifying extreme climatic conditions for maize production using RZWQM in Siping, Northeast China

Climate change has a great influence on agricultural production, especially under extreme climatic condition. In this study, Root Zone Water Quality Model (RZWQM) was used to predict grain yields of maize in the Siping region, Northeast China during the period from 1951 to 2015; and the response of grain yield to main climatic variables was qualitatively analyzed, especially in three special years of 1954, 2000 and 2009. Results showed that 1°C increase for minimum, maximum and mean air temperatures may produce 1224 kg/hm2, 1860 kg/hm2 and 1540 kg/hm2 more grain yields, respectively, and seasonal rainfall amount of less than 450 mm, especially in the flowering and grain filling stages, greatly reduced grain yields. In the years of 1954, 2000 and 2009, grain yields were reduced by 41%, 47% and 40% compared to their mean value, respectively, correspondingly because of extra low temperature (lower by 2.1°C-2.3°C), less rainfall in grain filling stage (36 mm) and extra high temperature (higher by 1.7°C-1.8°C), and less seasonal rainfall (252 mm). To release extreme climate's effect on grain yield, we suggest providing supplementary irrigation in the flowering and grain filling stage when rainfall is much less in this stage and also choosing appropriate maize species based on the longtime weather forecast.