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1干旱播种至出苗:春季干旱(4~5月),正是春玉米播种的季节。干土层厚度5cm以上,会推迟播种。此时降水稀少,土壤表层的湿度占田间持水量小等于50%,对出苗和苗期生长不利,苗不齐。植株矮小、细、弱,根系发育受阻,甚至造成叶片凋萎植株死亡。此时若干旱,每旬降水量不足20mm,总雨量不足50mm或表层土壤湿度占田间持水量低于60%,造成玉米晚播或出苗不好。拔节以后植株开始进入旺盛生长阶段,对水分要求迫切,抽雄前10d和后20d是水分临介期。穗分化及开花期对水分的反应敏感,此时正是伏旱和伏秋连旱易发生期,
1 Drought to sowing: Spring drought (April ~ May) is the season of spring maize sowing. Dry soil thickness of 5cm or more, will delay planting. At this time scarce precipitation, soil surface moisture accounted for less than 50% of the field water, germination and seedling growth adverse, seedlings missing. Plant short, thin, weak, blocked the development of roots, and even caused the withered leaves of plants died. At this time a number of dry, less than 20mm per ten days of precipitation, the total rainfall of less than 50mm or surface soil moisture accounts for less than 60% of the field water, resulting in late corn sowing or emergence is not good. After the jointing plant began to enter the vigorous growth stage, the water requirements are urgent, tassel 10d and after 20d is the water of the intervening period. Spike differentiation and flowering of the response to water sensitivity, this time it is the drought and volt autumn even prone to drought,