黄土旱塬不同覆盖对春玉米产量及土壤环境影响

对黄土旱塬用不同覆盖对春玉米产量及土壤环境影响的研究表明，春玉米采用不同覆盖技术，均有显著的增产效果，能显著增加土壤贮水量，使土壤上层长期保持湿润状态，提高土壤温度(除秸秆覆盖外)，降低昼夜温差，避免降雨直接冲击地面。保持良好的土壤结构，渗水地膜覆盖与秸秆覆盖、常规地膜覆盖和不覆盖相比，其产量分别增长6．4％、23．6％和29．1％，水分利用效率分别为21．5、20．2、17．4和16．7kg·mm^-1·hm^-2，秸秆覆盖还能提高土壤有机质，增加土壤肥力渗水地膜和常规地膜具有相同的增温效果，当气温达到35℃以上时，渗水地膜还具有降低极端温度的调节功能，但是，覆盖易造成有机质大量矿化和NO3^--N的淋失。

Effect of different mulching on spring corn yield and on soil environment in Loess Plateau

Effects of different mulching on spring corn yield and on soil environment in Loess Plateau, Heyang County were studied. The results showed that different mulching could increase the corn yield significantly. Soil water contents were increased remarkably except normal plastic film mulching, and the upper soil layer kept wet for a long time. Mulching could also reduce temperature difference of day and night, keep soil surface from direct precipitation lash, and maintain better soil structure. Compared with straw mulching, normal plastic film and no mulching, water osmosis plastic film could increase the yield by 6.4%, 23.6% and 29.1%, the water use efficiency 21.5, 20.2, 17.4 and 16.7 kg.mm-1.hm-2, respectively. Straw mulching could remarkably increase soil organic matter and soil fertility. Water osmosis plastic film had the same effect of increasing temperature as normal plastic film. While air temperature was more than 35 degrees C, water osmosis plastic film had the function of reducing extreme temperature, but long term mulching would promote excessive mineralization of soil organic nitrogen and leaching of NO3(-)-N.