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黄河中游地区的黄土高原,丘陵起伏,沟壑纵横,气候干旱,植被覆盖率低,水土流失严重。实践表明:要从根本上改变水土流失地区的自然面貌,改善农牧业生产条件,促进生态平衡,营造水土保持林是一项带根本性的措施。为了对水土保持林的小气候效益作出鉴定,研究它的水热状况和调节气候的作用,中国科学院林业土壤研究所在甘肃省天水县选择水土保持林(洋槐林)进行小气候对比观测,现将观测结果分析如下。一、观测地的自然概况和观测点的布设观测地选择在渭河支流(耒昔)河下游南岸的吕二沟小流域内(距天水市7公里),属黄土丘陵沟壑区第三副区,沟壑纵横,水土流失严重。据吕二沟流域测验,每年一平方公里流失水量57,300立方米,流失泥沙量为9,400吨。该区气候春季干旱,夏季多雨,年降水量540
In the middle reaches of the Yellow River, the Loess Plateau is characterized by rolling hills and ravines, arid climate, low vegetation coverage and severe soil erosion. Practice shows that it is a fundamental measure to fundamentally change the natural appearance of soil and water loss areas, improve farming and animal husbandry production conditions, promote ecological balance and create soil and water conservation forests. In order to appraise the microclimate benefit of soil and water conservation forest, and study its hydrothermal status and climate regulation, the Institute of Forestry and Soil Science, Chinese Academy of Sciences chose microclimate comparative observation in Tianshui County, Gansu Province to select soil and water conservation forest The results are analyzed as follows. I. The natural overview of the observation area and the layout of observation sites The observation area is selected within the Lv Ergou Small Watershed on the south bank of the lower reaches of the Weihe River (7 km away from Tianshui City), and is the third sub-district in the loess hilly and gully area. Gully vertical and horizontal, soil erosion is serious. According to the Lv Ergou Watershed Test, 57,300 cubic meters of water were lost per square kilometer per year and the amount of sediment lost was 9,400 tons. The climate in this area is dry in spring and rainy in summer with an annual rainfall of 540