覆膜对旱地麦田土壤水分及氮素平衡的影响

通过大田试验研究了平膜穴播和垄膜沟播等覆膜方式对晋南旱地麦田土壤水分、氮素平衡及产量的影响,以期在当地确立一套适宜的科学覆膜方式,为晋南旱塬地区乃至我国旱作小麦的高产优质提供理论依据。结果表明,垄膜沟播和平膜穴播处理的冬小麦增产效果显著,且以平膜穴播处理的效果最优,较测控施肥处理的籽粒产量和生物产量分别提高22.71%和25.45%。经过冬小麦一个生育期对土壤水分的吸收利用,两种覆膜处理的耗水量较不覆膜处理有较大的提高,而其水分利用率略低于不覆膜处理,但差异不显著。两种覆膜处理也能提高麦田的降水生产效率和休闲效率,较不覆膜处理分别提高9.46%—30.16%和9.95%—39.22%。覆膜有利于氮的矿化,并能促进小麦对氮素的吸收利用,同时也可以在一定程度上降低氮素在土壤中的残留,最终有利于小麦增产。

Effect of plastic film mulching on soil water and nitrogen balance in dryland wheat fields

Soil moisture and nitrogen are two major factors that limit wheat yield in northern China. Previous studies have investigated the effects of different film mulching methods on soil water, nitrogen balance, and yield in dryland wheat fields. The present study consisted of four treatments, including farmer mode (no film mulching), a control treatment (no film mulching), and two film mulching methods, either ridge film furrow sowing or flat film dibbling. We aimed to identify a suitable film mulching method for Loess Dryland Plateau and to establish a theoretical basis for producing high-yield and high-quality wheat in southern Shanxi, as well as in other areas in China. The results indicated that ridge film furrow sowing and flat film dibbling increased winter wheat yield and that the effect of flat film dibbling was greater. Compared with the control treatment, the grain and biological yields of the flat film dibbling treatment increased by 22.71% and 25.45%, respectively, and grain yield was also positively correlated with spikes per hectare (correlation coefficient=0.838), indicating its importance in increasing grain production. The water consumption of ridge film furrow sowing and flat film dibbling treatments were higher than the other treatments during the whole growth period, whereas their water use efficiency was slightly lower, although not significantly. Interestingly, compared to the farmer and control treatments, film-mulched winter wheat absorbed more water from deep soil (100-200cm). More specifically, the deep soil water that was consumed by the ridge film furrow sowing wheat accounted for 48.88% of the total soil water storage, whereas that of the control treatment only accounted for 35.75%. Plastic film mulching also increased the rainfall production and leisure efficiencies of wheat fields by 9.46%-30.16% and 9.95%-39.22%, respectively. Plastic film mulching promotes the mineralization of nitrogen, which can promote the absorption and utilization of nitrogen by wheat, reduce the residual nitrogen of soil, and increase the yield of winter wheat. Overall, both ridge film furrow sowing and flat film dibbling effectively improved the uptake and utilization of soil water and nitrogen by winter wheat, thereby increasing the yield of winter wheat. The observation that film mulching promotes the utilization of deep soil water by winter wheat should be investigated further, so as to better evaluate characteristics of soil moisture consumption in different soil layers.