黄土丘陵区生物结皮对土壤可蚀性的影响

Effects of biological soil crust on soil erodibility in Hilly Loess Plateau Region of Northwest China

在采样分析生物结皮对土壤理化属性影响的基础上,采用EPIC模型估算与模拟降雨试验相结合的方法,研究了黄土丘陵区不同生物量、不同土壤质地和不同季节的生物结皮对土壤可蚀性(K值)的影响.结果表明:生物结皮显著降低了土壤可蚀性,生物结皮层土壤可蚀性较下层土壤降低17%;土壤可蚀性随生物结皮生物量的增加呈降低趋势,藓结皮土壤可蚀性K值较藻结皮土壤降低21%;生物结皮土壤可蚀性在不同季节因其生物活性不同而存在差异,雨季中显著高于雨季前和雨季末;不同质地土壤上生物结皮对可蚀性的影响不同,可蚀性K值为砂壤>粉壤>砂土;模拟降雨条件下测定表明,生物结皮的发育使土壤可蚀性较对照(下层5～10cm土壤)降低约90%.

Based on the analysis of the effects of biological soil crust （biocrust） in re-vegetated grasslands on soil physical and chemical properties, and by using EPIC estimation model in combining with simulated rainfall trials, this paper studied the effects of biocrust with different biomass and different soil texture on the soil erodibility （K value） in Hilly Loess Plateau Region of Northwest China in different seasons. The results showed bioerust could significantly decrease soil erodibility, with the K value of biocrust soil decreased by about 17%, compared with subsoil. The soil erodibility decreased with the increasing biomass of biocrust. The K value of moss crust soil decreased by 21%, compared with different seasons, being with eyanobacteria crust soil. The erodibiliy of biocrust soil differed significantly higher in rainy season than before or after the rainy season due to the differences in the biological activity of the biocrust organisms. The erodibihy of biocrust soil with different texture also varied significantly, with the K value in the order of sandy loam soil 〉 silt soil 〉 sandy soil. The measurement under simulated rainfall showed that the development of biocrust could decrease the erodibility of biocrust soil by about 90%, compared with that of the subsoil （5-10 cm）.