不同粒径砾石覆盖对土壤水分蒸发的影响

Effect of Different Grain Size Gravel Covered on Soil Evaporation

2007年在水利部水土保持监测中心采用花盆整体称重法，对5种不同粒径砾石覆盖下的土壤水分蒸发效应进行了研究。结果表明，不同粒径砾石覆盖可以有效减少土壤蒸发，与CK相比，2～4mm粒径的土壤日蒸发量降低最多，降幅可达44％，粒径越大，土壤蒸发越多。蒸发过程中，日均蒸发量2～4mm〈4～6mm〈6～8mm〈8～10mm〈CK，砾石覆盖对土壤累积蒸发量影响显著（P=0．01）。砾石覆盖后土壤蒸发分为两个阶段，第一阶段蒸发速度由覆盖物的特性决定；第二阶段对蒸发速度起主要影响的是土壤含水量，土壤蒸发总体上表现出前期快、后期慢的趋势。不同粒径砾石覆盖可以降低土壤温度的变幅，2～4mm砾石覆盖地表温差降低幅度最大，为对照的66％，砾石覆盖的降温速率整体上低于CK。

The test was made in soil and water conservation monitoring center in 2007, based on flowerpot nature evaporation, the evaporation effect under five different size gravel covered was studied. Results show that： gravel covered reduces soil evaporation effectively, compared to CK, the day evaporation decreased degree of 2-4 mm is 44%, which is the most, the more evaporation the grater size, the evaporation order is 2-4 mm〈4-6 mm〈6-8 mm〈8-10 mm〈CK. The evaporation process can be divided into two stages, the first is determined by material characteristic, the later is determined by soil water content, the total evaporation trend takes on fast followed by slow. Soil temperature decreased degree is different, 2-4 mm size is the most, which is 66 % of CK, the temperature decreasing rate of gravel covered is lower than CK.