降水对玉米产量的影响及边际产量效应分析

THE EFFECT OF PRECIPITATION ON CORN YIELD AND THE ANALYSIS OF MARGINAL YIELD DFFECT

在黑龙江省玉米农田生态系统中，降水是限制玉米产量的主要因子．这种限制只能在环境、生产诸因子投入数量一定格局下，才是稳定的。玉米产量随降水量的多少而变化，在降水适量时玉米产量达到最高、旱涝均减产．降水的边际产量与各生态因子的关系是：降水边际产量随降水量递增而下降；随积温升高而增加；随土壤有机质含量的提高逐渐下降。对玉米适当增施氮、磷、钾化肥和农肥，玉米的降水边际产量效应均提高。在降水充沛，热量资源丰富的地区，配施适量的氮、磷钾化肥和农肥，玉米的生产潜力会得到充分发挥。

n corn field ecosystem, precipitation is main factor to limit corn yield. Cornyield changes with the amount of precipitation, and gets its highest POint Underadequate water condition, but decreases when it is too dry or too waterlogged.The marginal yield effect of precipitation decreases with the increase ofprecipitation input. which are highly negative correlated, increases with the riseinaccumulated temperature and decreases with the increase of soil organic mattercontent. With the adequately incrasing input of N. P. K and manure, highinarginal yield effect of precipitation can be get. In the areas of enough precipitation and abundant heat resource, with the accordant combination of fertilizers andmanure, the corn yield potential can be thoroughly developed.