基于GIS的黄丘区土壤水分制图及其定量化分析

Mapping and Quantitative Analysis of Soil Moisture Using GIS Techniques

以空间图形和数据库为基础,利用GIS把特定区域内的土壤水分样点数据与地理数据结合起来,建立不同利用类型——土地类型——坡度分级的浮点型土壤含水率字段,对流域尺度土壤水分制图及其定量化方法进行了研究和探讨,对不同土层土壤水分状态和分布进行了定量分析。研究结果表明从土壤水分结构看,安塞县土壤水分总体上处于较低水平,黄土丘陵区土壤水分环境非常恶劣,“土壤水库”的调节作用对于林木生长极其有限,大面积植树造林超越了“土壤水库”的供水和调水能力,是不适宜的,因此,在以适地适树原则适应土壤水分环境的同时,应加强土壤水分环境的改善和改良。

Soil water is crucial to plant growth and plays a vital role in re-vegetation.Based on spatial databases and sampled soil moisture data,a method was developed to relate the sampled soil water data to different combinations of land type-land use-slope grade thus using GIS techniques,and maps were made indicating the spatial variation of soil water in different soil layers.Using these maps,the authors calculated the amount and distribution of average soil water content in different soil layers in watershed scale.The results showed that the“soil water reservoir”had limited capability to adjust forest growth,and trees'planting on a large-scale was not feasible because its water consumption exceeded the supply of water from“soil water reservoir”.Quantitative analysis of the soil moisture structure demonstrated that soil water content in Ansai County was at a very low level as a whole.These findings showed that soil water environment was quite worse in Ansai County,and could not provide much water for vegetation restoration.Therefore,more efforts should be laid on the improvement of soil water environment while following the principle of selecting suitable tree species for sites in trees planting.