西藏“一江两河”流域中部地区草地资源特点

（西藏“一江两河”流域中部地区是自治区工农业经济最集中发达的地区，畜牧业生产在本区农业经济中占有一定的比重。本文阐述了本区草地的资源状况，生产力特点及草地的分布规律。研究发现：本区草地面积５２５．４万ｈａ，草地类型较复杂，垂直分布明显，牧草组成较丰富，营养价值较高。但草地生产力水平较低，平均产草量为１２７５－１３５０ｋｇ／ｈａ。从草地资源的水平分布格局看，存在着明显的南北差异，雅鲁藏布江以北占６３％以上。从时间分布看，存在着明显的季节性差异，其冬季的草地现存量仅为秋季的１０－３０％，但本区饲草饲料构成、分布格局与畜牧业生产是相协调的，构成了一个相对匹配的草地畜牧业整体。

CHARACTERISTICS OF THE GRASSLAND RESOURCES OF THE MIDDLE REACH AREA OF THE“ONE RIVER-TWO STREAMS”WATERSHED IN TIBET

The middle reach area of the “One Rive-Two Streams”watershed is a region in Xizang Autonomous Region where the industrial and agricultural economy is most concentrative and developed. In this area, animal husbandry occupies an important position in the agricultural economy. This paper illustrates the state of the grassland resources and the characteristics of the productive force and the distributive regularity of the grassland of the area. The study has found that the grassland area is about 5.254 million ha, the grassland types are relatively complicated, the vertical distribution of the grassland is obvious,the forage composition relatively plentiful, and the nutrition value of the forage is relatively high. But the grassland productive force is relatively low. The average yield is about 1275-1350kg/ha. Viewed from the horizontal distribution pattern of the grassland resources, there is an obvious diversity between the north and the south. The proportion of the grassland on the north side of the Yaluzongbu River exceeds 63%.Viewed from the distribution time of grassland, the season diversity is notable. The grassland yield in winter is only 10-30%. But the composition and the distribution pattern of the forage grass in this area coordinate with the animal husbandry and they jointly form a relatively coordinative grassland-animal husbandry unity.