多年冻土区活动层土壤水分对不同高寒生态系统的响应

发布时间：2018-03-17 07:17

本文选题：多年冻土　切入点：高寒生态系统　出处：《冰川冻土》2014年04期 　论文类型：期刊论文

【摘要】：土地覆被变化对土壤水分的影响是生态水文学和流域水文学研究的关键问题,基于长江源典型多年冻土区不同高寒草地土壤水分的观测,结合降水、生物量(包括地上和地下)和土壤理化性质,研究了活动层土壤水分变化对不同高寒生态系统的响应.结果表明:高寒草甸生物量、土壤养分含量均比高寒草原高,且对降水响应更为强烈,致使高寒草甸土壤水分变异性弱于高寒草原.在土壤完全融化阶段,高寒草甸土壤活动层存在一个低含水层(50 cm左右)和两个相对高含水层(20 cm和120 cm),但高寒草原土壤水分在活动层剖面上有随深度逐渐增大的一致性趋势;在秋季冻结过程中,高寒草甸土冻结起始日滞后于高寒草原土3~15 d;在春季融化阶段,高寒草原土更高的含冰量需要更多的融化潜热.此外,表层土壤中(0~20 cm),高寒草甸土比高寒草原土有更大的持水特性,而在活动层中下部则呈现完全相反的结果,不同高寒生态系统的演替改变了土壤的水热迁移过程.
[Abstract]:The effect of land cover change on soil moisture is a key issue in the study of ecological hydrology and watershed hydrology. Based on the observation of soil moisture in different alpine grassland in typical permafrost regions of the Yangtze River source, it combines precipitation. The physical and chemical properties of biomass (including aboveground and underground) and soil were studied. The response of soil moisture change in active layer to different alpine ecosystems was studied. The results showed that the biomass and soil nutrient content of alpine meadow were higher than those of alpine grassland. And the response to precipitation is stronger, resulting in the soil moisture variability of alpine meadow is weaker than that of alpine steppe. There is a low aquifer of about 50 cm in active layer of alpine meadow soil) and two relatively high aquifers of 20 cm and 120 cm ~ (-1), but the soil moisture of alpine steppe is increasing with the depth of active layer, and in the course of freezing in autumn, the soil moisture of alpine meadow has a tendency of increasing with the depth of active layer. The initial freezing date of alpine meadow soil lags behind that of alpine steppe soil for 3 ~ 15 days. In the melting stage of spring, the higher ice content of alpine meadow soil needs more latent heat of melting. In the surface soil, the water holding capacity of alpine meadow soil is higher than that of alpine steppe soil, but the result is completely opposite in the middle and lower part of active layer. The succession of different alpine ecosystem changes the process of soil water and heat transfer.
【作者单位】：兰州大学资源环境学院;兰州大学西部环境教育部重点实验室;中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室;重庆市荣昌县水务局;
【基金】：国家自然科学基金项目(41271092) 国家重点基础研究发展计划(973计划)项目(2010CB951402;2012CB026101)资助
【分类号】：S152.7;P642.14

【相似文献】