荒漠草原4种主要植物群落枯落物层水土保持功能

Litter Layer of Soil and Water Conservation Function of Four Plant Communities in Desert Steppe

枯落物层是草地除冠层外,大气与矿质土壤层、植物根系层进行物质与能量交换的重要介质,在生态学中起着不可替代的作用。通过研究荒漠草原4种主要植物群落(蒙古冰草群落、甘草群落、赖草群落和沙蒿群落)水土保持功能,结果表明:荒漠草原4种植物群落枯落物层年截留率在4.58%～5.61%,截留量为22.77～27.87mm,且枯落物对降雨的截留量随降雨量增加而增大,而截留率随降雨量增加而减小,当降雨等级在0～2mm时,截留率为100%,当降雨等级高于2mm时,截留率随1次降雨降雨量的增加而减少。枯落物层抑制土壤蒸发的效应与枯落物层厚度的增加呈正相关,有枯落物层比无枯落物层覆盖的土壤蒸发量减少了19.25%～76.82%,但当土壤含水量升高为田间持水量的3/4时,不同植物群落枯落物减少土壤水分蒸发的效应有所不同。围封内枯落物对土壤风蚀的抑制显著低于围封外,枯落物对风蚀的抑制作用与枯落物的蓄积量呈正相关。

Litter layer is an important mediator of grass for the atmosphere and the mineral soil layer, the plant root zone material and energy exchange as the canopy, it plays an irreplaceable role in ecology. Soil and water conservation of the four major plant communities in the desert steppe（Mongolia wheatgrass community, licorice communities, leymus communities and artemisia communities） were researched. The results showed that： The litter layer＇s interception rate was 4.58~5.61~, interception was 22.77~27.87 mm in four kinds of desert steppe plant communities, and litter interception was increased with rainfall, while the rejec- tion rate decreased, when rainfall level was in the 0~2 mm, the interception rate was 100%, when the rain- fall level was higher than 2 ram, the interception rate increased with the decreased of rainfall. The effects of inhibition soil evaporation was positively correlated with thickness of litter layer, the evaporation of litter layer covering of soil was less 19.25% to 76.82% than uncovering, but when the soil water content was the field capacity of 3/4, the effects of different litters to reduce soil moisture evaporation was different. And enclosed within the litter on soil erosion in inhibition was significantly lower than the enclosure, the inhibitory effect of litter on the wind erosion was positive correlation with the accumulation of litter.