古尔班通古特沙漠生物结皮影响下土壤水分的日变化

对新疆古尔班通古特沙漠生物结皮影响下土壤水分的日变化特征进行了定量研究,结果表明:①无论是结皮覆盖区还是无结皮覆盖区,其土壤含水量随深度的变化均表现出明显的层次性,其中以距地表 20 cm处的土壤含水量最高.②结皮覆盖区距地表5 cm和10 cm处的土壤含水量显著高于无结皮覆盖区(LSD检验, p ＜0.05);而45 cm和60 cm处的土壤含水量则表现为结皮覆盖区极显著低于无结皮区(LSD检验,p＜0.05),说明生物结皮具有较强的保持土壤表层水分的能力.③结皮覆盖区与无结皮覆盖区土壤水分的日变化特征明显不同于距地表5 cm处,而其他各土层的变化趋势则较为一致.无结皮覆盖区距地表5 cm处土壤水分的日变化呈先上升后下降的趋势,而结皮覆盖区的变化则恰恰相反.

Study on Daily Change of Soil Moisture Content under the Effect of Microbiotic Crusts in the Gurbantonggut Desert, Xinjiang, China

Microbiotic crusts composed of different combinations of mosses,lichens,liverworts,algae,fungi,cyanobacteria and bacteria are extensively distributed in deserts all over the world.In this paper,an experimental study on the daily change of soil moisture content under the effect of microbiotic crusts in the Gurbantonggut Desert is carried out.The results are as follows:(1) Soil moisture content increases with increasing soil depth within a certain extent,it is the highest at soil depth of 20 cm,and then it decreases gradually.(2) LSD-test results show that the soil moisture content is significant higher at soil depths of 5 cm and 10 cm in the areas with microbiotic crusts compared with that in the areas without microbiotic crusts(LSD-test,p<0.05).However,the soil moisture content at soil depths of 45 cm and 60 cm in the areas with microbiotic crusts is much lower than that in the areas without microbiotic crusts(LSD-test,p<0.05),which reveals that the microbiotic crusts have high capability of maintaining topsoil moisture.(3) There is a significant difference in daily change of soil moisture content at depth of 5 cm between the areas with and without microbiotic crusts.Particularly,organic matter accumulation in topsoil of 0~5 cm in depth can maintain a relatively high soil moisture content,which is beneficial to the growth of ephemeral and ephemeroid plants in the Gurbantonggut Desert.