Abstract:

Less rainfall and drought is the main meteorological disaster for maize cultivation in central and western Jilin Province. To understand the water condition of local maize growing season and its influence on maize yield, and improve local drought monitoring, assessment and prevention capability during the maize growing season, we used farmland water surplus and deficit ratio to reveal the farmland water status of different maize growing stages of cities and counties in the province, and then adopted correlation coefficient and regression method to analyze the influence of water surplus and deficit on maize yield in the early, middle and late stage of maize growing in the representative cities and counties. The results show that the regional, annual and seasonal change of the surplus and deficit of farmland water in main maize producing areas of Jilin are significant, most cities and counties lack water all year round. Severe water shortage is observed in western Jilin, and eastern Jilin also have insufficient water supply. In most years, the western Jilin has water deficit rate during the early, middle and late stage of maize growing for about 50%, 15% and 35%, respectively, and the water deficit rate is approximately 30% for the early stage and 10% for the late stage of maize growing in eastern Jilin, with a surplus during the middle stage. The annual changes of the water surplus and deficit ratio are very volatile, although to a large extent, the water surplus and deficit ratio in various cities and counties have synchronization and regional consistency on the time scale, there is no obvious trend of interdecadal change. The yield of maize is proportional to water surplus and deficit, and the water surplus and deficit in the growing season could largely determine the maize yield. Water deficit of more than 30% in the whole growing season could cause drought disaster to maize, and a deficit of more than 50% could result in more than 10% yield reduction.

Key words: maize production belt, growing season, water surplus and deficit, geographical distribution, ample and deficient yield, correlation analysis, Jilin Province