砂石覆盖粒径对土壤蒸发的影响

为研究不同粒径砂石覆盖对土壤蒸发过程的影响,进行模拟试验.试验以砂石粒径大小为因子,设3个粒径水平:0.5,2.5,4.5 cm,以裸土为对照.结果表明:地面砂石覆盖能够有效抑制土壤蒸发,在土壤含水率较高的阶段,抑制作用更加明显;砂石覆盖对蒸发的抑制作用与砂石粒径密切相关,在相同的覆盖厚度(5 cm)和同一含水率条件下,砂石覆盖的粒径越大,对蒸发的抑制能力越低;砂石覆盖能明显改变土壤蒸发过程,覆盖条件下的土壤蒸发与裸土相比不仅降低而且更加平稳;在41d的连续蒸发过程中,覆盖条件下的累计土壤蒸发量与时间呈近似线性关系,而裸土为对数关系.

Effects of mulching sand and gravel size on soil moisture evaporation

Simulating experiments were conducted to study the effects of sand and gravel mulches with different sizes on moisture evaporation from soil surface. Sand and gravels with the diameters of 0.5, 2.5, 4.5 cm were used in the experiments and bare surface was taken as contrast. The results indicate that the sand and gravel mulches can efficiently inhibit soil moisture evaporation, especialy at the high level of soil water content. Under the same soil water content and sand and gravel mulches with thickness of 5 cm, inhibitory effects of gravel mulches on the evaporation are negatively correlated with sand and gravel size obviously. Compared with bare surface, the sand and gravel mulches can reduce the soil mositure evaporation and make it at a lower and stable level. The relationship between cumulative soil moisture evaporation and time can be discribed by the linear function under sand and gravel mulching, but logarithm function under bare surface during the successive evaporation of 41 days.