丘陵山地区耕地水约束状态研究——以黎香溪流域为例

Study on the Constrained State of Water in the Arable Land of the Hilly and Mountainous Regions—A Case of Lixiangxi Watershed

建立一种土壤水循环机理与地形特征结合的层次评价模型,以长江一级支流——黎香溪流域为研究区,以土壤的蓄水量、土壤地形湿度、蒸散发量和灌溉用水条件作为评价因子,采用层次分析法对流域耕地水约束状态进行综合分析,将水约束状态分为轻度、一般、较重、重度、极重5个等级。通过对300个样本的抽样调查,分析结果总体正确率为78%。灌溉条件的影响力随着约束等级的降低而增加,正确率随着约束等级的降低而降低,从极重到轻度正确率分别为85.00%、81.67%、78.33%、75.00%和68.33%。流域内耕地受用水较重及以上程度约束占总面积的55%。模型对流域内部耕地用水状态的相对差异模拟精度较高,灌溉水平的差异是误差的主要来源。

This study established a hierarchical evaluation model of soil water cycle mechanism combined with topographic features. Taking a case of Lixiangxi river basin which is a tributary of the Yangtze river,constrained state of water in the arable land of Lixiangxi watershed was comprehensively analyzed by AHP method considering the evaluation factors such as water storage capacity of the soil,soil terrain moisture,evapotranspiration,irrigation water conditions. The constraint state of water in arable land was divided into five grades as mild, medium,intense,severe,and very severe. The results showed that overall accuracy was 78% through a survey of 300 samples. The influence of irrigated increased with the decreased of the constraint state grades while the accuracy decreased with the decrease of constraint state grades,and the accuracy were85.00%,81.67%,78.33%,75.00% and 68.33% from very severe to mild,respectively. The constraint state of water on 55% of the total area in the watershed was the severe or very severe grades. This model had high simulation accuracy on the relative difference of the water use state in arable land in the watershed, and the difference of irrigation level was the major source for the error.