用灰色系统GM（1，1）模型预测棉花生产

Prediction of Cotton Production in China in 2000 Years with GM(1,1) Model of Gray System

近年来由于自然灾害、比较效益等因素的影响，棉花生产出现较大波动，这种非线性变化给预测工作带来了困难。本预测对以往灰色系统ＧＭ（１，１）模型进行了二点改进：（１）利用高斯主元素消去法解算未知参数，在计算方法上是一大改进，同时提高了运算速度和计算精度；（２）加入了迭代计算。通过建立误差方程式，给定收敛条件和趋近次数，使模型的拟合精度提高。预测２０００年棉花面积将达到６２８万公顷，总产５７６．５６万吨，标准误差分别为７４．３８公顷和±８９．４４万吨。考虑到９０年代以来棉铃虫的危害，预测值加上标准差下限，就是未来较低水平下的棉花生产趋势。

The cotton production in China has been unstable significantly in recent years be-cause of the insect, disease and lower comparative profit.With the improved GM(1 ,1) modelof gray system , he cotton production of China could be forecasted more accurately,Accordingto the forecast result, the cotton planting acreage will be 6. 28 million ha, the prduction 5.77million tons in 2000 years,and the standard error will be土0.74 million ha and土0.89 milliontons.