温性荒漠草地蒿类半灌木合理需水量探讨

文中对新疆伊犁河流域温性荒漠草地蒿类半灌木生物量随水分条件的变化规律进行了研究。结果显不：随着灌溉水量的增加,单位面积蒿类生物量明显表现出先增加然后下降的变化规律。据灵敏度（Sk）计算,灌溉水量在433kg／（m^2·a）时,Sk存在最大值,表明此时地表生物量对灌溉水量变化的响应最为灵敏。根据灵敏度变化曲线将不同灌溉水量下地表生物量变化分为3个区间。灌溉水量在（226kg／（m^2·a）-778kg／（m^2·a））区间,蒿类生物量增加的幅度超过灌溉水量变化的幅度,实施此灌溉水量可得到最优恢复效果。因此恢复当地草地的合理水量范围确定在（226k/（m^2·a）-778kg／（m^2·a））。从水资源利用的效率

Discussion on the rational water content for restoring semi-shrub Artemisia in desert grassland

Aiming at the status of the severe degeneration of desert grassland in Yili river valley,different water irrigation for semi-shrub Artemisia experiment were conducted for two years.The variation of aboveground biomass per square of semi-shrub Artemisia with different water content was studied.The results showed that with increasing water content,aboveground biomass of semi-shrub Artemisia increased distinctly firstly and then declined.The regression relationship between water content and aboveground biomass of semi-shrub Artemisia was: Y=0.00000001x3-0.0002x2 +0.795x+138.28(P<0.001,R2=0.962).Based on the result of the sensitivity index,the variation ratio of the aboveground biomass of semi-shrub Artemisia was maximum,namely SK=0.624 when the irrigated water content was 433kg/(m2·a) while SK was <0 at irrigated water content of more than 1498kg/(m2·a).This indicated that the aboveground biomass of semi-shrub Artemisia began to decline with increasing water content of more than1498kg/(m2·a).According to the change of the sensitivity curve with different irrigated water content,variation of aboveground biomass of semi-shrub Artemisia could be divided into three ranges.The variation ratio of aboveground biomass of semi-shrub Artemisia was greatly significant and the increased degree of the aboveground biomass of semi-shrub Artemisia exceeded more than that of the irrigated water content at the water content range of 226kg/(m2·a)~778kg/(m2·a).Therefore the rational range of the irrigated water content for restoring the local grassland was 226kg/(m2·a)~778kg/(m2·a).From the water utilization efficiency,it is reasonable that irrigated water content of 228kg/(m2·a) is regarded as the minimum water demand for restoring semi-shrub Artemisia in the study area.