不同覆盖模式对土壤水分蒸发的影响

Effect of different mulching modes on soil moisture evaporation

为了揭示不同覆盖模式抑制土壤水分蒸发的效果,通过模拟试验,对不同覆盖模式抑制土壤水分蒸发的效果进行了分析.试验设置无覆盖(CK)、覆砂(S)、覆砂+覆膜(SM)、覆秸秆+覆膜(JM)和覆秸秆+覆砂(JS)5种模式.结果表明:土壤表层不同覆盖处理的土壤日蒸发量不同,在蒸发初期,土壤水分蒸发量从大到小依次为CK,JS,JM,S,SM,之后基本保持CK,JS,S,SM,JM的变化趋势.当有降雨发生时,土壤水分蒸发量从大到小由CK,JM,SM,JS,S变为CK,JS,S,SM,JM的趋势;土壤表层的不同覆盖处理可有效减少土壤水分的蒸发,CK,JS,JM,S,SM处理的土壤水分累积蒸发量分别为1823.6,712.2,473.3,450.6,375.1 g,与对照相比,CK,JS,JM,S,SM处理的土壤水分累积蒸发量分别减少了60.9%,74.0%,75.3%,79.4%;在整个蒸发过程中,不同覆盖模式下土壤水分累积蒸发量与时间的关系符合W=atb,综合分析可知,覆砂(S)处理是最符合试验区域的覆盖模式.

To reveal the effect of restraining soil water evaporation with different mulching models, through simulation test, the effect of restraining soil water evaporation was analyzed. Five modes were set up including bare land （CK）, sand mulching （S）, sand and plastic film mulching （SM）, straw and plastic film mulching （JM） and straw and sand mulching （JS）. The results show that the soil daily evaporation capacity is different with the different mulching modes of soil surface. In the early evaporation, the soil moisture evaporation capacity is CK 〉 JS 〉 JM 〉 S 〉 SM, then the change trend becomes CK 〉 JS 〉 S 〉 SM 〉 JM. When rainfall occurs, the change of soil moisture evaporation capaci- ty is from CK 〉 JM 〉 SM 〉 JS 〉 S to CK 〉 JS 〉 S 〉 SM 〉 JM. The different mulching models can effec- tively reduce soil water evaporation. Soil water cumulative evaporation capacity of bare land, straw and sand mulching, straw and plastic film mulching, sand mulching, sand and plastic film mulching is respectively 1 823.6,712.2,473.3,450. 6 and 375. 1 g, soil water cumulative evaporation capacity of straw and sand mulching, straw and plastic film mulching, sand mulching, sand and plastic film mulching decreases by 60.9% , 74.0% , 75.3% and 79.4% respectively, compared with CK. In the whole evaporation process, the relationship between soil water cumulative evaporation capacity and time under different mulching models is W = at^b. By comprehensive analysis, sand mulching is a more reasonable mulching model in the test area.