【摘要】 保水保土是石漠化治理的关键,掌握石漠化区土壤水分的变化规律对石漠化治理有重要的作用。2017年6月—2018年11月在重庆酉阳县龙潭槽谷两侧顺、逆倾坡(典型石漠化治理区)选择4个土壤剖面分15 cm、30 cm土层深度埋设探头,开展高分辨率土壤水分和土壤温度的动态监测。结果表明:(1)季节尺度上,土壤水分与降雨量的关系较大,与土温的关系较小;顺倾坡土壤水分高于逆倾坡,且多雨季节比少雨季节明显;多雨季节,裸岩出露影响降雨的再分配:顺倾坡得到双重补给,即降雨补给、裸岩地表径流补给。(2)降雨间歇期,顺倾坡失水量较逆倾坡少,这主要与坡面坡度和土壤质地的差异有关。(3)降雨期间,降雨强度较小时,土壤水分随土层深度的增加而增加;但降雨强度较大时,顺倾坡土壤监测点出现表层土壤水分大于底层土壤水分的现象,这主要与强降雨引起坡面的超渗产流有关。(4)受龙潭槽谷顺、逆倾坡空间差异的影响,槽谷两侧裸岩出露率、土层厚度、土壤有机质等自然要素差别明显,进而对该区土壤水分的时空分布有重要影响,因此在石漠化治理过程中应采取不同的保水保土措施。更多还原

【Abstract】 Soil and water conservation is the key to controlling rock desertification. Understanding the pattern of changes in soil moisture in rocky desertification areas plays an important role in rock desertification control. In this study, a high-resolution positioning for the dynamic monitoring of soil moisture and temperature was applied to four slope lands with 15 and 30 cm depths. This research was conducted from June 2017 to November 2018 in sloping and reversed slopes on both sides of Longtan karst trough valley(typical rock desertification control area), Youyang, Chongqing City. Results showed the following:(1) On a seasonal scale, soil moisture was closely related to rainfall, and slightly associated with soil temperature. The soil moisture levels of sloping slope were higher than those of reversed slope, and this phenomenon was more evident on rainy season than on less rainy season. On rainy season, rock outcrops affected the redistribution of rainfall. The sloping slope obtained double replenishment, that is, rainfall recharge and runoff recharge of the bare rock surface.(2) On continuous sunny days, the soil moisture loss of sloping slope was lower than that of reversed slope. This occurrence was mainly related to the difference between slope and soil texture.(3) At a low rainfall intensity, the soil moisture increased with the soil depth. At a high rainfall intensity, the soil moisture of the sloping slope at the surface(15 cm) was greater than that in the deep layer(30 cm). This phenomenon was mainly associated with the slope ultra-fluidity mechanism.(4) Influenced by the spatial difference in the Longtan trough valley, natural elements, such as rock outcrops, soil thickness, and soil organic matter, on both sides of the valley evidently differed. Moreover, the spatial difference has an important influence on the spatial and temporal changes of soil moisture. Thus, different water and soil conservation measures should be implemented in rock desertification control.更多还原