作物不同发育阶段天气对产量的影响。播种前:即使在播种前也有一些对产量产生影响的重要因子。例如,美国玉米带西部,土壤的底墒特别重要。7月和8月初是需水的高锋时期,正常降雨量不能充分满足作物的需水量,因而作物就利用土壤中的贮水。虽然,从伊利诺斯往东,一般来说,春季土壤的田间持水量比较大,土壤的贮水量对以后的产量并不产生多大 Effect of weather on crop yield at different development stages of crops. Before sowing: There are some important factors that affect the yield even before sowing. For example, soil moisture is particularly important in the western United States corn belt. In July and early August, during the Gao Feng period when water was needed, normal rainfall did not adequately meet the crop’s water requirements, and crops utilized water stored in the soil. Although, from Illinois to the east, in general, spring field soil water holding capacity is relatively large, soil water storage capacity for future production does not have much