Change of grassland productivity and strategy in Aletai Prefecture, Xinjiang Province

Based on Remote Sensing and Geographic Information System and field survey, historic document (grassland classification map, grassland grade map, grazing map before 1985) was combined with 2002 MODIS data and field yield data in comparison analysis, the ratio of available grassland, edible forage, and grassland utilization, i.e. K1, K2, K3, were determined, forage yield model for each type of seasonal grassland was established, forage yield, theoretical stocking rate, seasonal grassland stocking rate and grassland grade for whole prefecture and each county were calculated, the comparison analysis of theoretic, threshold and practical stocking rate was conducted, the information of grassland productivity change and relevant strategy were provided.