地膜覆盖对土壤水温和春小麦产量形成的影响

通过大田试验研究了地膜覆盖对土壤水温状况及春小麦产量形成的影响．结果表明，地膜覆盖对土壤的增温作用在春小麦生育期内呈“U”型变化，地膜覆盖可以通过防止蒸发和提升土壤深层水分至作物可利用层来增加土壤中有效水含量，利于作物利用．地膜覆盖的增温保墒作用利于作物前期生长和水分利用，在生育后期覆膜，作物根系发育受到抑制，作物蒸散量和水分利用效率下降，影响产量的形成．对照(CK)、播前灌水(W)、全程覆膜(M)、播前灌水 覆膜30d(WM30)、播前灌水 覆膜60d（WM60)及播前灌水十全程覆膜(WMw)6个处理的产量分别为2554、2424、2750、3138、3305、3123kg·hm^-2，最佳覆膜时间在40—60d．

Effects of plastic film mulching on soil temperature and moisture and on yield formation of spring wheat

Field experiments were carried out to study the effects of plastic film mulching on soil temperature and moisture, and on yield formation of spring wheat. The results showed that plastic film mulching could increase soil temperature with "U" variances in the whole growth period of spring wheat. Plastic film mulching could also increase soil available water by restraining evaporation and elevating deep water to the layer useable for roots. The promotion of soil temperature and soil water content under plastic film mulching was favorable to the development and water use of spring wheat in its earlier stage. Root developments were restrained when mulching in later stage of spring wheat, with decreases in crop water consumption and water use efficiency, and there was no significant effects on yield formation. The spring wheat yields under control (CK), pre-sowing irrigation (W), mulching for whole stage (M), pre-sowing irrigation adding mulching for 30 days (WM30), pre-sowing irrigation adding mulching for 60 days (WM60), and pre-sowing irrigation adding mulching for whole stage (WMw) were 2 554, 2,424, 2,750, 3,138, 3,305, and 3,123 kg.hm-2, respectively, and the optimum mulching time was at 40-60 days.