摘要
Sampling and testing are conducted on groundwater depth and vegetation coverage in the 670 km2 of the Sangong River Basin and semi-variance function analysis is made afterwards on the data obtained by the application of geo-statistics. Results showed that the variance curve of the groundwater depth and vegetation coverage displays an exponential model. Analysis of sampling data in 2003 indicates that the groundwater depth and vegetation coverage change similarly in space in this area. The Sangong River Basin is composed of upper oasis, middle ecotone and lower sand dune. In oasis and ecotone, influenced by irrigation of the adjoining oasis, groundwater level has been raised and soil water content also increased compared with sand dune nearby, vegetation developed well. But in the lower reaches of the Sangong River Basin, because of descending of groundwater level, soil water content decreased and vegetation degenerated. From oasis to abandoned land and desert grassland, vegetation coverage and groundwater level changed greatly with significant difference respectively in spatial variation. Distinct but similar spatial variability exists among the groundwater depth and vegetation coverage in the study area, namely, the vegetation coverage decreasing (increasing) as the groundwater depth increases (decreases). This illustrates the great dependence of vegetation coverage on groundwater depth in arid regions and further implies that among the great number of factors affecting vegetation coverage in arid regions, groundwater depth turns out to be the most determinant one.
Sampling and testing are conducted on groundwater depth and vegetationcoverage in the 670 km^2 of the Sangong River Basin and semi-variance function analysis is madeafterwards on the data obtained by the application of geo-statistics. Results showed that thevariance curve of the groundwater depth and vegetation coverage displays an exponential model.Analysis of sampling data in 2003 indicates that the groundwater depth and vegetation coveragechange similarly in space in this area. The Sangong River Basin is composed of upper oasis, middleecotone and lower sand dune. In oasis and ecotone, influenced by irrigation of the adjoining oasis,groundwater level has been raised and soil water content also increased compared with sand dunenearby, vegetation developed well. But in the lower reaches of the Sangong River Basin, because ofdescending of groundwater level, soil water content decreased and vegetation degenerated. From oasisto abandoned land and desert grassland, vegetation coverage and groundwater level changed greatlywith significant difference respectively in spatial variation. Distinct but similar spatialvariability exists among the groundwater depth and vegetation coverage in the study area, namely,the vegetation coverage decreasing (increasing) as the groundwater depth increases (decreases). Thisillustrates the great dependence of vegetation coverage on groundwater depth in arid regions andfurther implies that among the great number of factors affecting vegetation coverage in aridregions, groundwater depth turns out to be the most determinant one.
基金
National 973 Program for Basic Research
No.G1999043506
关键词
地下水位
植被覆盖
空间变异
干旱地区
geo-statistics
groundwater level
groundwater depth
arid regions
vegetation coverage
semi-variance function
spatial variation
kriging