吉林省粮食主产区玉米生长季水分盈亏及其对产量的影响

少雨干旱是吉林省中西部玉米栽培的主要气象灾害。为了弄清当地玉米生长季水分条件及其对产量的影响,提升当地玉米生长季干旱监测、评估和防御能力,采用农田水分盈亏缺率揭示域内各县市玉米不同生长季农田水分状况,用相关系数和回归方法分析代表县市玉米生长前期、中期、后期水分盈亏对玉米产量的影响。结果表明,吉林省玉米主产区农田水分盈亏率地域和年、季变化明显,多数县市常年缺水,西部县市水分严重亏缺,东部水分也不足。西部多数年份玉米生长前、中、后期分别缺水50%、15%和35%左右,东部县市前、后期缺水为30%和10%左右,中期水分有余。水分盈亏率年变化很不稳定,各县市水分盈亏率在较大程度上存在时段上的同步性和区域上的一致性,无明显年代变化趋势。玉米产量与水分盈亏呈正比,生长季水分盈亏在很大程度上决定玉米产量丰欠。全生长季水分亏缺30%以上会产生玉米干旱灾害,亏缺50%以上导致减产10%以上。

Water Surplus and Deficit of Maize Growing Season and Its Effect on Yield in Major Grain Producing Areas of Jilin Province

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.