风速和秸秆覆盖对土壤水分蒸发影响的模拟试验研究

Impact of wind-speed and straw-mulching on soil water evaporation

通过室内模拟试验方法,研究了不同风速(静风、0.5、1.5 m/s)和秸秆覆盖量(0、4 120、8 240 kg/hm2)对土壤水分蒸发的影响。结果表明:(1)土壤水分蒸发受风速和秸秆覆盖的明显影响,当土壤含水量大于田间持水量的70%、覆盖量一定时(0、4 120 kg/hm2)时,风速0 m/s与1.5 m/s之间的土壤日蒸发量差异均显著;而秸秆覆盖量达到8 240 kg/hm2时,风速对土壤蒸发量没有显著影响。当土壤含水量大于田间持水量的55%、不同风速处理时,土壤累积蒸发量随覆盖量的增大而显著减少。(2)土壤水分累积蒸发量(E)与时间(t)之间呈显著的指数关系(E=atb),而且参数a和b与风速和秸秆覆盖量处理存在明显的关系。

The impacts of wind-speed and straw-mulching on soil water evaporation were measured and analyzed with 9 treatments of three wind-speeds（calm wind,0.5 or 1.5 m/s） and three straw-mulching levels（0,4 120,or 8 240 kg/hm2）.The results showed that when the water content was 70% of the field moisture capacity and mulching（0,4 120 kg/hm2） was the same,the soil water evaporation with wind-speed 1.5 m/s was significantly higher than other treatments;when the water content was higher than 55% of the field moisture capacity,the cumulative soil water evaporation with no mulching and wind-speed 1.5 m/s was far more than that of other treatments.There lies an exponential relationship between the cumulative soil water evaporation（E） and time（t）（E=atb）,and the parameters（a and b） have clear differences among the treatments of wind-speed and straw-mulching levels.