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通过野外径流场模拟降雨试验,研究玉米秸秆覆盖对砂土和壤土产流产沙过程的影响,探索不同土壤质地下水土保持的临界秸秆覆盖条件。处理分为2种土壤质地类型和5个水平的秸秆覆盖度:0、10%、20%、30%和40%。结果表明:壤土抗侵蚀能力优于砂土,但透水性弱于砂土;不同土壤质地条件下秸秆覆盖效益存在差异,相同的秸秆覆盖时,砂土条件下的土壤侵蚀防治效果优于壤土;2种土壤质地条件秸秆覆盖度30%时可显著提高土壤入渗总量(25.7%~33.9%),减少产沙总量(22.2%~46.4%),对水土流失具有良好的防治效果。考虑到过大的秸秆覆盖度(大于80%)会造成播种机堵塞,在华北保护性耕作研究实践中,建议砂土和壤土质地下的农田地表保持1 600~3 000 kg/hm2(30%~60%)的玉米秸秆覆盖,以达到较好的水土保持效果和播种质量。
By simulating rainfall experiment in field runoff field, the effects of corn straw mulching on runoff and sediment yield of sand and loam were studied, and the critical straw mulching conditions for soil and water conservation under different soil quality were explored. Treatments were divided into two types of soil texture and five levels of straw coverage: 0, 10%, 20%, 30% and 40%. The results showed that the soil erosion resistance was better than sand soil, but the water permeability was weaker than sand soil. The straw mulching benefits were different under different soil texture conditions. Soil erosion control effect was better than loam soil under the same straw mulching. The results showed that the total soil infiltration capacity (25.7% -33.9%) and the total sediment yield (22.2% -46.4%) were significantly improved by 30% straw mulching with 2 kinds of soil texture conditions, which had a good control effect on soil erosion. Considering that excessive straw cover (more than 80%) will cause blockage of planter, in the practice of conservation tillage in North China, it is suggested that the surface of farmland under sandy and loamy soil should be kept at 1 600 ~ 3 000 kg / hm2 (30% ~ 60%) of corn stalks to achieve better water and soil conservation and sowing quality.