Review of clear plastic film mulch on spring wheat in semi-arid loess plateau
Review of clear plastic film mulch on spring wheat in semi-arid loess plateau
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发表时间：
2001
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通讯作者：
Liu Xiao
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作者：
Liu Xiao
在黄土高原半干旱地区开展的春小麦地膜覆盖试验结果表明，地膜覆盖在提高水分和养分利用率、提高粮食产量方面可以起到非常重要的作用。因为地膜覆盖可以通过改善耕层土壤生态环境条件，即改善水热状况来活化土壤养分。但近年来，通过生产实践和科学试验，人们越来越发现，而全生育期长期地膜覆盖也会带来严重的问题：例如，在作物生长的前期和中期，覆盖地膜的作物通常比不覆盖地膜的作物生长得更好，因此在以前情况的整个生长阶段，通过蒸腾作用会损失更多的土壤水分，土壤水分的蒸散（蒸发+蒸腾）损失比不覆盖地膜严重得多，在作物生长后期，如果降水量少或无降水，额外的灌溉补水，会造成严重的水分胁迫现象，并会显着抑制小穗分化，最终导致收获指数和作物产量下降；同时，地膜覆盖的增产效果必须付出沉重的代价，在一定程度上耗尽土壤肥力特别是有机质。因此，不正确的地膜覆盖方法（例如全生育期覆盖地膜）有时不但没有明显的增产效果，而且还容易造成土壤养分的流失。特别是土壤中硝酸盐的流失和积累，肥料利用率下降，土壤生态条件恶化，土壤肥力下降，作物高产也难以持续。因此，在确定地膜覆盖模式时，必须综合考虑土壤初始湿度状况、生育期降雨情况、播后地膜覆盖期以及氮肥施用等因素。
The results of plastic film mulching experiments for spring wheat carried out in the semi arid areas on the loess plateau show that plastic film mulching can play a very important role in the aspect of increasing water and nutrient utilization efficiency and in increase of grain yield.Because plastic film mulching can activate soil nutrient by means of improving soil ecological and environmental conditions in the plowed layer,namely,improving water and heat status.But in recent years through production practice and scientific experiments,people increasingly find that irrational and long term plastic film mulching during the whole growth period also cause serious problems:for example,during the early stage and medium stage of crop growth,the crops mulched by plastic film usually grow better than those no mulching plastic film,so during the whole growth stage of former situation more soil water will lose through transpiration,the evapotranspiration (evaporation+transpiration) loss of soil water will be much more serious than that no plastic film mulching,during the late growth period of crops if precipitation is little or no additional water is supplemented to irrigation,this will lead to serious water stress phenomena,and will significantly inhibit small spike differentiation,this finally will lead to decrease of harvest index and crop yields;in the meantime,the yield increase effect under plastic film mulching must be paid heavy cost such as exhaust soil fertility especially organic matter to some extent.Therefore,incorrect plastic film mulching method (for instance mulching plastic film during the whole growth period ) sometimes will not only has no significant yield increase effect,but also easily cause the loss of soil nutrient in particular the loss and accumulation of nitrate in the soil,decreasing the fertilizer utilization efficiency,deterioration of soil ecological condition,decline of soil fertility,and high crop yield will also not maintain sustainable.So deciding the model of plastic film mulching,these factors such as initial soil moisture status,rainfall condition during the growing period,plastic film mulching period after sowing and nitrogen fertilizer application etc must be taken into account.