黄土区退耕草地凋落物-土壤界面水分过程特征研究

Hydrological Processes of Litter-Soil Interfacial Systems in Restoration Grasslands of the Loess Plateau,China

为研究不同退耕年限草地下垫面层凋落物对土壤蒸发过程和表层土壤保水特征的影响,通过室内模拟试验,以黄土高原地区不同退耕年限草地凋落物质量为因子,依据野外退耕还草5a,15a,30a的草地凋落物覆盖特征,设3个凋落物处理水平,以裸地为对照,比较分析了不同草地枯落物特征对地表土壤界面的水分过程影响效应。研究结果表明:具有凋落物处理能够有效地延缓径流的产生,并能显著增加表层土壤持水量;凋落物持水量与凋落物质量呈显著线性正相关;在降雨后24h内,凋落物层抑制土壤蒸发作用比较明显;随着凋落物含量的增加,72h后表层土壤含水量显著提高。在黄土高原干旱半干旱地区,耕地退耕后凋落物的增加显著改善了地表土壤的持水能力,提高了表层土壤水分含量。

Simulating rainfall experiments were conducted to study the effects of litter layer on moisture evaporation and water storage capacity of the litter-soil interfacial systems.In this experiment,four treatments were designed,litter layers of grassland naturally restored for 5,15,and 30 years were mulched on the surface soil and bare surface soil was taken as contrast.The results showed that the litter layer treatments not only delayed the runoff emergence,but also increased the water-hold quantity significantly.The relationship between the litter mass and litter storage water can be described by the linear function.The results indicated that the litter layers can efficiently inhibit soil moisture evaporation,especially at the high level of litter-soil interfacial systems water content during the successive evaporation of 24 hours.After the 72 hours,the soil water content of the surface soil increased significantly with the increase of restoration years,while the proportion of cumulative evaporation of the rain-hold quality decreased.In the semi-arid loess plateau region,the litter layer of the restoration grassland could improve the water holding capacity of the surface soil and increase the soil water content.