半干旱黄土高原地区地膜覆盖和底墒对春小麦生长及产量的影响

在年均降水量为415mm的半干旱地区黄绵土旱地上，以春小麦为供试作物进行大田实验，研究不同底墒(包括低底墒、中底墒和高底墒)下．地膜覆盖(包括不覆膜、播种后覆膜30d、覆膜60d和覆膜120d即全程覆膜)进程对作物生产的影响。结果表明．增加底墒和合理的覆膜进程均会显著增加作物的生长和产量，但底墒不同，其最佳覆膜进程不同：在低底墒时，覆膜处理反而使产量低于不覆膜处理；在中底墒时．覆膜30d产量最高，随着覆膜时间延长．产量呈下降趋势，甚至全程覆膜产量低于不覆膜处理；高底墒以覆膜60d产量最高。综合作物生长和产量，全程覆膜并没有多少实际意义。在同种覆膜处理下，随着底墒的增加，根生物量、地上干物质、叶面积及产量也增加显著，高底墒覆膜60d处理的产量在所有处理中为最高。

Effects of plastic film mulch and pre-sowing soil water on growth and yield of spring wheat in semi-arid areas of Loess Plateau

A field experiment was carried out on cultivated loessial soil in semi arid areas with 415 mm annual mean precipitation and spring wheat ( Triticum aestivum L.) was used as tested crop to study the effects of the period of plastic film mulching (including non mulching,mulched 30 d,mulched 60 d and mulched 120 d after sowing) under different pre sowing soil water (including low pre sowing soil water,medium pre sowing soil water and high pre sowing soil water).The experiment showed that the best mulched period was mulched 60 d under high pre sowing soil water,mulched 30 d under medium pre sowing soil water and non mulching under low pre sowing soil water.Mulched 120 d did not have significant effect on growth and yield of crops.In the same mulched treatments,the root biomass,dry matter aboveground,leaf area,tiller number,and yield increased with increasing pre sowing soil water.The yield of mulched 60 d under high pre sowing soil water was the highest in all treatments.