EFFECTS OF DIFFERENT GRAZING INTENSITIES ON THE VEGETATIVE COVER OF THE GRASSLAND OF RED CLOVER AND RYE GRASS AND ON SOIL NUTRIENT
不同放牧强度对红三叶、黑麦草草地植被和土壤养分的影响

In this paper, the laws of changes of plants and soil under different grazing intensities are studied. The results show as follows. High-intensity grazing applied over a period of three years induces comparatively big changes in the total nitrogen content of soil and in the composition and structure of the grassland. It causes the herbage yield to decrease by 17.1%,the importance value of the main species of the grassland, namely, red clover, to decrease by 33.8%, the coefficient of homogeneity of red clover to increase by 51.1%, and the nitrogen-phosphorus ratio of soil to increase by 1.3. Low-intensity grazing causes the total nitrogen content of soil to decrease by 0.096%, and the coefficient of homogeneity of red clover to increase by 21.0%. Moderate-intensity grazing does not cause the herbage yield and the importance value of red clover to decrease. Meantime it keeps the coefficient of homogeneity of red clover far below the 1.0 level but causes the total nitrogen content of soil to decrease by 0.085%. From the above results it can be concluded that moderate-intensity grazing is the best option of grazing management for keeping the sustained high production of the grassland.