陇中地区降水量对小麦产量的影响

为探讨生育期降水对小麦(Triticum aestivum)产量的作用机制和规律, 以甘肃省定西市1971-2005年小麦产量和各生育期降水量为研究对象, 运用APSIM模型模拟, 并用二次多项式逐步回归法分析了生育期降水量对小麦产量的影响。结果表明, 小麦产量除与年降水总量有关外, 还与生育期降水量的变化有关。不同生育期降水量对小麦产量影响表现为苗期拔节期挑旗期抽穗期灌浆期开花期, 其中, 苗期和拔节期的降水量与小麦产量呈开口向下抛物线型变化。且苗期和拔节期降水量效应分别是挑旗期降水量效应的6.6和3.7倍, 而抽穗期、挑旗期、开花期和灌浆期降水量对小麦产量影响在研究区降水范围内出现二次叠加递增变化。甘肃陇中地区小麦产量的主要限制因子是苗期和拔节期降水量。

Impacts of precipitation on wheat yield during growth period

In order to explore the mechanism and regular pattern of precipitation on wheat yield, the impacts of precipitation from 1971 to 2005 on wheat yield during its growth period were imitated using APSIM model and quadratic polynomial stepwise regression analyzed in Dingxi City, Gansu province. The results showed that wheat production was not only affected by total annual precipitation, but also the variations of growth period precipitation. The most effective precipitation period was seedling stage and followed by jointing stage, carry flag stage, heading stage, filling stage and flowering stage. The correlation between precipitation and wheat yield during seedling stage and jointing stage showed downward opening parabola. Effects of precipitation in seedling stage and jointing stage were 6.6 and 3.7 times of precipitation in carry flag stage, respectively. Effects of precipitation in heading stage, carry flag stage, flowering stage and filling stage on wheat yield showed secondary superposition incremental trends during the studied area. The precipitation in seedling and elongation stage was one of main limit factors of wheat yield in this studied area.