西北地区县域农业水资源平衡问题研究

水土资源不匹配和水资源时空分布不均的自然本底,加之人口大量增加和经济高速发展的驱动,使得西北地区农业水资源供需矛盾十分突出。论文系统分析了县域单元农业水资源平衡的两个层次及其计算方法,并对西北地区314个县域单元进行了实证研究。天然状态下农田水量平衡模型计算结果表明:西北地区各个县域单元降水均不能满足各种作物的水分需求,亏水为水量平衡的首要特征。就各省而言,新疆为亏水量最高的省份,其多年平均作物亏水量达628.02mm,陕西最小,其值为87.51mm。人工状态下水土资源平衡模型结果表明:受灌溉水平的影响,西北地区各个县域单元水量平衡差异明显。各省份中,新疆水土资源利用处于水少地多的超量承载状态,其它各省灌水量略有盈余,灌溉面积的扩大尚有一定潜力。

Study on the Agricultural Water Resources Balance in Northwest China

As land and water resources are out of proportion and the spatial,temp oral distribu,tion of water resources for agriculture is quite uneven in Northwe st China,it is important to study the agricultural water resources balance in th is region.This paper systemically analyzed the agricultural water resources bala nce from two hierarchical aspects and identified the calculation methods for bot h steps.Taking 314 counties as examples,it studied the agricultural water balanc e in Northwest China.Results showed that precipitation can not meet water demand of the crops,hence water deficit is the prime characteristic in water balance i n Northwest China.Deficits of all 12 crops were 898.28mm in Tulufan county,and t he precipitation satisfied ration ranged from 2.74% to 3.71&; for different crops .Total water deficits of 12 crops in Xinjiang reached to 628.02 mm,and the preci pitation satisfied ration was only 13.65%.So water deficit was serious in Xinjia ng.The precipitation satisfied ration was 82.37% in Shaanxi province,and the sit uation was the best.Satisfaction ration for different crops were not the same,as for vegetables and rice,since the water demand was much higher than the other c rops,the satisfaction ration was the worst,but the case for potato and hemp was the best.The results showed that even irrigation water was taken into account,it still can not meet the crop water demand in Xinjiang.In the year 2000,the net i rrigation water demand was 141.95×108m3,the water supply can't meet its demand, and the total water deficits were 18.24×108m3.The irrigation water can basicall y meet the water demand in other provinces,water surplus was 9.42×108m3 in Shaa nxi,7.87×108m3 in Gansu,7.38×108m3 in Qinghai,and 23.33×108m3 in Ningxia.Ther e is still certain potential to enlarge irrigated areas in these provinces.