适宜绿洲规模数学模型的比较研究——以且末为例

根据且末绿洲综合分析的基础上,基于水量平衡法和适当的水热平衡绿洲规模数学模型,分析了且末绿洲适宜的发展规模,得出以下结论:①且末绿洲总面积为992.16 km^2,现耕地总面积为150.88 km^2;②通过水量平衡法计算的且末适宜绿洲规模为1 062.67 km^2,且末绿洲适宜耕地面积为336.59 km^2。绿洲的现有规模及现有耕地面积比适宜规模小,需增加70.51 km2的绿洲面积和185.71 km^2的耕地面积。可知,可以扩大绿洲面积,然而不能确定稳定性。③通过水热平衡法计算且末绿洲适宜规模为609.22~812.29 km^2,适宜耕地面积为92.66~123.55 km^2。即绿洲的现规模和现耕地面积远超适宜规模,同样超出适宜规模及适宜耕地面积的0.2~0.6倍。绿洲面积不宜再扩大。④结合且末绿洲的实际情况,且末绿洲稳定性指数约为0.5358,且末绿洲处于亚稳定状态,生态系统退化,绿洲需要较高的投入才能保持稳定。因此,水热平衡的适宜绿洲规模数学模型符合且末适宜绿洲规模计算的模型。

Comparison of Mathematical Models for Describing CropResponses to N Fertilizer

Four mathematical models were systematically evaluated in describing responses of four different cropsat 7 rates of nitrogen application. Residual sum of squares and a total point ranking method were used toassess the model fitting for crop responses to nitrogen application. Sparrow’s inverse quadratic polynomialmodel performed the best.