祁连山海北冬春气温变化对草地生产力的影响

THE INFLUENCES OF WINTER-SPRING'S AIR TEMPERATURE CHANGE ON GRASSLAND PRODUCTIVITY IN HAIBEI AT QILIAN MOUNTAIN

祁连山海北地区冬春气温与高寒草甸牧草产量具有很高的反相关关系。冬春气温升高导致牧草产量有所下降，主要原因是冬春气温升高，使冬季土壤冻结层变薄，土壤水分散失严重；在牧草营养生长阶段初期，又正值我国北方天气气候“干旱”胁迫最严重的时期，自然降水量显得不足，进而限制了牧草生长发育的水分需求，最终影响到牧草年产量的提高。对冬春气温进行主成分处理后建立的气温影响牧草产量的回归关系表明，回归模型拟合率较高，试报１９９５年牧草产量误差很小，效果良好。

Grass production of Alpine Meadow is highly negatively correlated with winter-spring air temperature of Haibei at Qilian mountain. The rising of winter-spring air temperature leads to the decrease of grassland production, and this is maily because that the rising of winter-spring air temperature makes winter frozen layer thinning and soil water lossing seriously. At the beginning of nutritional growing period,faced with the most severe“drought” pressure and deficient natural precipitation in North China, the requisite water for grass growing and developing are limited, and the rise of grassland production is ultimately limited. analysing the winter-spring air temperature by EOF, a regression model is set for the effects of air temperature on grass production. The regression results show that the fitting rate is relatively high, the results of prediction for 1995 show the model's erros is small,and the effect is very good.