桂西北环境移民迁入区不同利用方式坡地土壤水分动态变化

Effects of Landuse on Dynamic Change of Soil Moisture in Immigrant Demonstration Area of Northwest Guangxi Province

土壤水分是土地开发利用和生态环境建设的关键性限制因子。利用2006年4—9月土壤水分定位观测数据,研究了桂西北环境移民迁入区坡地开发后不同利用方式土壤水分的时空动态变化规律。结果表明,不同土地利用方式间土壤储水量变化与降雨量变化基本一致;在时间尺度上,不同月份各利用方式土壤储水量差异显著,0—1 m平均储水量依次是坡耕地>园地>荒草地>灌丛>林地;在空间尺度上,不同利用方式土壤储水量为中等变异,在表层(0—20 cm)荒草地和灌丛的土壤储水量较大,在深层(60—100 cm)坡耕地和园地土壤储水量较大;不同土地利用结构土壤水分从坡顶到坡脚呈增加趋势,但修筑梯田的坡地较自然坡地土壤水分沿坡面变化幅度小。

Soil water is a critical factor of eco-environmental construction and land exploitation. Based on the fixed observation in the immigrant demonstration area of Northwest Guangxi Province from April to September in 2006, the dynamic change of soil water on hillslope with various landuse types was analyzed. Results showed that the dynamic change of soil water storage had the similar trend with the change of rainfall. In temporal scale, soil water storage in 0-1 m layer had the significant differences among various landuse types. Landuse types rankes in the decreasing order of slope farmland, orchard land, wasteland, natural shrub land, and arbor woodland. In spatial scale, soil water storage on hillslope was in moderate variation and had some differences among various landuse types. Soil water storage of grassland and shrub land was higher in 0-20 cm layer, but it was higher on slope farmland and orchard land in 60-100 cm layer. Soil water had the increasing trend from the top down to the bottom along the hillslope with the different landuse structures. However, the range of variation for soil moisture along the hillslope with contour terrace was smaller than that of natural slope.