宁夏灌区压减水稻面积对水环境的影响

Effect of reducing rice planting area on water environment in Ningxia irrigation area

从向空气中输送水分的角度,分析宁夏灌区压减水稻面积的不利影响。结果表明,减少1万hm^(2)水稻面积,其中一半改种玉米、另一半改种小麦,就会减少水分蒸散量3.032×10^(7) m^(3),在集中连片种植,静风条件下,近地层范围内,4—9月空气相对湿度减少11.6%。若灌区压减10%~30%的水稻,改种玉米和小麦,每年全灌区向空气中输送水量减少2.5×10^(7)~7.4×10^(7) m^(3),地下水位下降29.3~87.8 mm。可见,维持水稻面积对生态的贡献是巨大的。

From the perspective of transporting water to the air,the adverse effects of reducing rice planting area in Ningxia irrigation area were analyzed.The results showed that reducing the rice area of 10000 hm^(2),half of which was changed to corn area and the other half to wheat area,the water evapotranspiration would reduce by 3.032×10^(7) m^(3).Under the condition of concentrated continuous plant⁃ing and calm wind,the air relative humidity would decrease by 11.6%from April to September.If the irrigation area reduced rice area by 10%~30%and changed to corn area and wheat area,the water transported to the air in the whole irrigation area would reduce by 2.5×10^(7)~7.4×10^(7) m^(3),the groundwater level droped by 29.3~87.8 mm every year.It could be seen that the contribution of maintaining rice area to ecology was huge.