水土保持研究

针对岩溶石漠化地区土壤含水量(Soil Water Content,SWC)和土壤温度(Soil Temperature,ST)的野外连续监测及相关研究较少,为深入探讨岩溶石漠化地区SWC和ST的动态变化规律及其耦合特征,在云南省蒙自市岩溶断陷盆地的典型高原石漠化地区择点,对气象因素和10 cm,40 cm,80 cm深度SWC,ST进行了一整年连续监测,结合多元统计和水热传输理论进行了分析。结果表明:(1)高原石漠化地区不同深度的SWC在非集中降雨期浅层大于深层,集中降雨期深层大于浅层。降雨停止后SWC迅速衰减至初始状态,浅层土壤干湿交替迅速,集中降雨有利于深层SWC补给;(2)基于多元统计的冗余分析(Redundancy Analysis,RDA)讨论了SWC和ST的影响因素,结果表明SWC的影响因素主要为降雨、日累计辐射、气温和蒸散发,ST的影响因素主要为气温,降雨对于SWC的方差解释率仅为39.5%,而气温对于ST方差解释率为77.4%;(3)在土壤物质与能量传输方面,越靠近地表的土壤在热传导方面作用越明显、热储存作用越弱,0—40 cm深度的土壤基本为向下传热层,40—80 cm土壤主要储存热量或向上传热。土壤蒸汽水夏秋季储存、春冬季排放,蒸汽水通量变化曲线与热通量变化曲线趋势近乎相同,ST是蒸汽水运移的主控因素。热量和蒸汽水储存在土壤中,可为石漠化地区的植被恢复提供条件。

The field monitoring and related researches on soil water content(SWC)and soil temperature(ST)in rocky desertification areas with bare rock are in deficiency. We select the typical plateau rocky desertification area in the karst fault basin of Mengzi City, Yunnan Province, and monitored the meteorological elements and SWC and ST continuously at depths of 10 cm, 40 cm and 80 cm for a whole year. We analyzed the data by combining multivariate statistics and hydrothermal transmission theory. The results show that:(1)once the rain stops, the SWC quickly decays to the initial state, resulting in alternation of wetting and drying continually in the shallow soil; the concentrated rainfall is beneficial to the deep soil water supply in the area; the shallow ST is affected by meteorological factors and has frequent fluctuation;(2)the influencing factors of SWC and ST are analyzed based on redundancy analysis( RDA ); the main factors affecting SWC are rainfall, daily cumulative radiation, air temperature and evapotranspiration; the main factor affecting ST is just the air temperature; the overall interpretation rate of rainfall for SWC is 39.5%, and the overall interpretation rate of temperature for ST is 77.4%;(3)the soil heat conduction in near the surface is more obvious, and heat storage in near the surface is weaker; the soil in 0—40 cm layer is basically a downward heat transfer layer, while soil in the 40—80 cm layer mainly stores heat or transfers heat up. Soil vapor water stores in the summer and autumn, and soil vapor water releases in the spring and winter. The vapor flux curve and the heat flux curve have the synchronous trend, indicating that soil temperature is the main controlling factor on vapor migration. Heat and vapor stored in the soil can support vegetation restoration in rocky desertification areas.