青海省达日县退化草地研究 Ⅱ 退化草地成因分析与评估

通过对１９８５年至１９９７年两次草地畜牧业资源调查资料的分析认为，达日县产草量和载畜量的年减少量分别为３万ｔ青草和ｌ万个羊单位；黑土滩增加到８１８．９７ｋｍ２。在个别地区、个别时间、局部草地有超载，但从整体上讲，整个草地并不过牧；全球气温升高所引起的荒漠化，应是处于半干旱—半湿润干旱区的达日县草地退化、大片黑土滩产生的主要原因。

Causes of Grassland Degradation in Dari County of Qinghai Province

Through an analysis on the grassland survey data in 1985 and 1997, it appeared that the forage yield and stocking capacity of grasslands in Dari couty had been declining at a rate of 30 000 tonne and 10 000 sheep units per year respectively. The area of severely degraded grassland (bare spots of black earth) had increased to 818.97 km 2. In some places and in some periods overstocking did occur, but the grassland as a whole was not overgrazed. The degradation of local grasslands could be due to the global change in increased temperature.