不同覆盖模式下土壤返盐及水盐运移规律

干旱地区地表蒸发引起土壤水分的散失是造成盐分表聚的重要原因之一,土壤表层进行覆盖处理可改变地表结构,从而影响土壤水分蒸发和盐分迁移过程,本研究旨在通过野外田间试验,研究不同覆盖模式下土壤返盐及水盐运移规律。结果表明:土壤表层进行不同覆盖处理均可有效抑制土壤水分蒸发,土壤保水效果为:覆砂+覆膜覆秸秆+覆砂覆砂覆秸秆+覆膜无覆盖(CK);随土层深度的增加,土壤含水率减小的趋势逐渐减缓。不同覆盖处理也可有效抑制土壤盐分表聚,缩小盐分在土壤中迁移的范围;覆盖处理的土壤盐分向上迁移主要发生在0~20 cm范围内,无覆盖处理在0~35 cm范围内,覆盖后可较好地抑制土壤返盐。综合考虑认为砂石覆盖模式是较适合该试验区的覆盖模式。

Soil resalinization and water-salt movement under different mulching modes

The loss caused by surface evaporation in arid area of soil moisture is one of the important reasons for the crop yield under gravel - sand mulching .Gravel-sand mulching can change the surface structure ,thus affecting the evap-oration of soil water and water - salt movement .This paper studied soil resalinization and water-salt movement under dif-ferent mulching modes through a field test .The result showed that the different mulching modes on soil surface could ef -fectively inhibit soil water evaporation .For effect on soil water retention ,the significance of different modes was as the follows :sand and plastic film mulching (SM)> straw and sand mulching (JS)> sand mulching (S) > straw and plastic film mulching (JM)> bare land (CK) .The trend of soil moisture content became gradually decreased with the increase of soil depth .The different mulching mode could also effectively inhibit top enrichment of soil salt ,and reduce the range of salt movement in the soil .Soil salt upward migration occurred mainly in the range of 0 ~ 20 cm soil layer ,and oc-curred mainly in the range of 0 ~ 35 cm layer without mulching ,indicating that mulching inhibited soil resalinization .In conclusion ,the sand mulching (S) is a more suitable mulching mode in the test area .