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生物土壤结皮覆盖下风沙土入渗特征及模拟
刘翔
学位类型硕士
导师周宏飞
2016
学位授予单位中国科学院大学
学位授予地点北京
学位专业自然地理学
关键词生物土壤结皮 干旱荒漠区 风沙土 土壤水分 入渗 模拟
摘要干旱荒漠区广泛分布着生物土壤结皮(BSCs),探索BSCs对土壤入渗的影响,对于深入揭示荒漠地区水分循环过程具有重要的意义。本文以古尔班通古特沙漠南缘的BSCs为研究对象,基于野外原位实验与室内模拟实验等方法,探究藓类、地衣和藻等3种类型BSCs覆盖下风沙土的入渗特征。主要结论如下 1、BSCs覆盖对风沙土水分入渗过程有着重要影响:与无结皮覆盖的风沙土对照相比,3种类型BSCs均显著降低了风沙土初渗速率,藓类结皮、地衣结皮、藻结皮覆盖下初渗速率降低幅度依次为36.10%、46.42%、50.39%;藓类结皮、地衣结皮和藻结皮覆盖下风沙土稳定入渗率区间依次为2.205-2.799 mm/min、1.622-2.283 mm/min和1.128-2.254 mm/min,藓类结皮、地衣结皮(p<0.05)和藻结皮(p<0.05)均明显降低了风沙土稳渗速率,降低幅度依次为17.81%、34.57%和45.04%;3种类型BSCs均限制了湿润锋在风沙土中的推进过程,表现为:藓类结皮、地衣结皮、藻结皮的渗漏时间分别为裸沙对照的2.13、3.04和2.98倍;各类型BSCs均减小了风沙土累积入渗量,阻碍了风沙土水分入渗,与裸沙对照相比,藓类结皮、地衣结皮、藻结皮的1 h累积入渗量分别降低16.10%、28.56%和26.56%。 2、各类型BSCs覆盖下风沙土累积蒸发量均大于裸露沙地。总体来看,地衣结皮覆盖下风沙土蒸发能力最强,藓类结皮次之,而藻结皮最弱,藓类、地衣和藻结皮覆盖下风沙土5-9月累计蒸发量分别是同条件下裸沙地的1.09、1.14和1.01倍。BSCs所固定的水分在相对较长的时间内维持较高的蒸发速率,从而增加了降水在雨后散逸损失的可能性。可见,BSCs覆盖总体上减少了降水入渗补给土壤水分的能力。 3、在本实验条件下,Kostiakov模型最适用于模拟不同类型BSCs覆盖下风沙土水分入渗过程,Horton模型模拟效果次之。
其他摘要In arid region, soil water condition is the key factor for the desert ecosystem. Soil water infiltration capacity profoundly affects the redistribution of precipitation, and is of crucial importance for the storage and utilization of precipitation. The Gurbanttunggut Desert is the largest fixed and semi-fixed desert in China. It is covered by well-developed biological soil crusts( mosses, lichens, alage, fungi, cyanobacteria and bacteria). To explore the effects of BSCs on water infiltration plays an important role in revealing the characteristics of water circulation in this area. In this study, three typical types of biological soil crusts (moss, lichen and algal crusts) in the Gurbantunggut Desert were selected and sevaral experiments were used to examine the effect of biological soil crusts on the process of soil infiltration and evaporation. The results indicated that the effect of biological soil crusts on soil water infiltration was significant. Firstly, all three types of biological soil crusts decreased the initial infiltration rate significantly, but they differed in the degree of the reduction. The moss crusts, lichen crusts and algal crusts decreased the initial infiltration rates by 36.10%、46.42% and 50.39% respectively. The stable infiltration rate of sandy soil covered by the moss crusts, lichen crusts and algal crusts are as floow: 2.205-2.799 mm/min、1.622-2.283 mm/min and 1.128-2.254 mm/min. The moss, lichen(p<0.05)and algal crusts(p<0.05 also can decrease the stable infiltration rate by 16.50%、33.98% and 35.92% respectively. Secondly, movement of wetting front was slower in soils covered with these three types of biological soil crusts than in bare soil. The leakage time of soil under moss, lichen and algal crusts were respectively 2.13, 3.04, and 2.98 times that of bare soil. Thirdly, all three types of biological soil crusts reduced the cumulative infiltration volume. Relative to the bare soil, the reduction rates of moss, lichen and algal crusts are 16.10%、28.56% and 26.56% respectively. The effect of biological soil crusts on soil water evaporation was also significant. From may to september, the cumulative evaporation of sandy soil covered with the moss, lichen and algal crusts were 1.09, 1.14, and 1.01 times that of the naked soil. Over all, the sand covered by lichen crust has the strongest evaporation capability,and algal crust weakest. The moisture fixed in the BSCs maintain a higher rate of evaporation in a longer time, so most of them will loss through evaporation after precipitation. The soil covered by BSCs generally reduces the ability of precipitation that transform into the soil moisture. In this experimental situation, the Kostiakov equation is most applicable to describe the infiltration processes of sandy soil covered by the three types of biological soil crusts, and the Horton equation was the next best option.
学科领域自然地理学
语种中文
文献类型学位论文
条目标识符http://ir.xjlas.org/handle/365004/14732
专题研究系统_荒漠环境研究室
作者单位中科院新疆生态与地理研究所
推荐引用方式
GB/T 7714
刘翔. 生物土壤结皮覆盖下风沙土入渗特征及模拟[D]. 北京. 中国科学院大学,2016.
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