喀什地区近10a绿洲耕地变化及其地下水位效应分析

Cultivated land change and it's ground water level response in Kashghar in last decade

根据喀什地区绿洲耕地面积和地下水位实测数据,分析近10a来耕地面积和地下水的变化特征及其之间的关性。分析表明:1)近10a绿洲耕地面积呈现波动增加的态势,年均增长率3.40%,人均耕地面积经历从减少到增加的变化过程,年均递增1.14%;耕地空间变化区域差异明显,巴楚县耕地变化率最大,年均达11.49%,岳普湖县最低,为1.08%。2)地下水埋深基本规律是喀什噶尔河-叶尔羌河上游区地下水位较深,而在中下游及灌区的地下水位较浅。近10a全区地下水位平均下降0.67m,喀什噶尔河流域下降0.85m,叶尔羌河流域下降0.52m。年内月最高和最低水位相差0.37m,喀什噶尔河流域为0.55m,叶尔羌河流域为0.23m。4月出现年内最高水位,6～7月出现最低水位。3)耕地面积与地下水位之间存在较好的负相关性,年末耕地面积与地下水位之间相关性为-0.87,年内新增加的耕地面积与地下水位之间相关性为-0.77。人为因素对地下水位年际和季节变化起得极为重要的作用。

Based on the statistical data of cultivated land and ground water in Kashghar,we analyzed the changing characters of cultivated land and ground water and it＇s correlation for last decade.The results showed that：①The cultivated land area showed fluctuated increasing trend in last decade,it＇s annual increasing rate was 3.04%,average occupation of cultivated land area went through a course of gradually increasing,annual increasing rate was 1.14%.The spatial disparity of the cultivated land changes was significant.The variation rate of cultivated land area in Barquk County was large,annual variation rate was 11.49%,however,The variation rate of cultivated land area in Yopurgha County was small,annual variation rate was 1.08%.②the regulation of ground water depth was as fallows： ground water level of upper reach of Zarapshan river and Kashghar river was deep;whereas ground water level of middle and lower reaches was shallow.The average dropping depth of ground water was 0.55m,average dropping level of ground water in Kashghar river watershed was 0.85m,average dropping level of ground water in Zarapshan river water shed was 0.52m in the last decade.The difference between the highest and lowest ground water level in a month was 0.37m,in Kashghar river watershed the difference was 0.55m,in Zarapshan river watershed the difference was 0.0.23m.The highest water level occurred in April,and the lowest water level occurred in Jun-July.③Correlation between cultivated land area and ground water level was negative.Correlation at the end of the year between cultivated land area and ground water level was-0.87,Correlation at the end of the year between new cultivated land area and ground water level was-0.77.Human factors played the most influential role in annual and seasonal variation of ground water level.