The impact of land use and land cover changes on soil moisture and hydraulic conductivity along the karst hillslopes of southwest China
The impact of land use and land cover changes on soil moisture and hydraulic conductivity along the karst hillslopes of southwest China
复制标题
土地利用和土地覆盖变化对西南岩溶山坡土壤水分和导水率的影响
DOI：
10.1007/s12665-009-0077-6
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发表时间：
2009-02
影响因子：
2.8
通讯作者：
shi,peng
中科院分区：
文献类型：
--
作者：
chen,xi;zhang,zhicai;chen,xunhong;shi,peng
了解土壤水分和水力特性的时空动态对于研究多种水文和生态过程至关重要。由于土层薄、土壤持水能力小，喀斯特环境极其脆弱。由于人口增加和农业面积扩大，农业用地和森林砍伐明显加剧，喀斯特环境更加脆弱。本研究分别采用时域反射仪和圭尔夫渗透仪对四个喀斯特山坡的土壤水分含量（SMC）和导水率（K）进行了现场测量，每个测试点都有不同的植被覆盖、地形、地表坡度、土壤性质和岩石碎片含量。测量统计结果表明，土地覆盖变化强烈影响土壤水分和水力特性的分布。与裸土区的SMC相比，森林区、灌丛区和草地区的SMC值分别高出30.5%、20.1%和10.2%。植被根系显着增加低层淤泥土壤的渗透性。森林、农业和裸露土壤区域的测量 K 值分别为 0.8、0.6 和 0.01 厘米/分钟。当森林因火灾或砍伐成为农业区或裸露土壤时，SMC将分别减少13.1%和32.1%。如果森林砍伐导致严重的石漠化，SMC就会减少70%。基岩裂缝显着降低了上覆层的SMC，但增加了K值。对于嵌入有裂缝和没有裂缝的岩石的土层，SMC 值将从 30-45% 分别减少到 17-30%。K 值可以从 1.0 增加到 8.5 厘米/分钟。 SMC 对地形很敏感。倾斜角增加 1° 将减少 SMC 约 0.82%。这些由土地覆盖和土地利用变化引起的变化为进一步研究生态系统演化对水动力过程的响应提供了有用的信息。
The understanding of the temporal and spatial dynamics of soil moisture and hydraulic property is crucial to the study of several hydrological and ecological processes. Karst environments are extremely fragile because of thin soil and small soil water holding capacity. A marked intensification of agricultural land use and deforestation due to increase of population and thus expansion of agricultural areas has made the karst environment even more delicate. In this study, the soil moisture contents (SMC) and hydraulic conductivities (K) along four karst hillslopes were measured in situ by time domain reflectometry and the Guelph Permeameter, respectively, at test plots, each of which has a different vegetative cover, landform, land surface slope, soil property and content of rock fragment. The statistical results from the measurements show that land cover changes strongly affect the distribution of soil moisture and hydraulic properties. Compared with SMC in the bare soil areas, SMC values are 30.5, 20.1 and 10.2% greater in the forest, shrub and grass areas, respectively. Vegetation roots significantly increase permeability of low-layer silt soils. MeasuredKvalues were 0.8, 0.6 and 0.01 cm/min for the forest, agriculture and bare soil areas, respectively. When the forest was destroyed by fire or cut to become an agricultural area or bare soils, SMC would be reduced by 13.1 and 32.1%, respectively. If deforestation leads to strong rock desertification, SMC was reduced by 70%. Bedrock fractures significantly reduce the SMC in the overlying layer, but increaseKvalues. SMC values of 30–45% would be reduced to 17–30% for the soil layer embedding rocks with and without fractures, respectively.Kvalues could be increased from 1.0 to 8.5 cm/min. SMC are sensitive to terrain. A slope angle increase of 1° would reduce SMC about 0.82%. These changes resulting from land cover and land use alterations offer useful information to further investigate the response of ecosystem evolution to hydrodynamic processes.
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