Evaluation of grassland productivity in Kizilsu Kirgiz autonomous prefecture of Xinjiang

The grassland vegetation index (NDVI) were selected to establish the model of estimation biomass in the Kizilsu Kirgiz Autonomous Prefecture by combing the MODIS data in July and August 2005 and the field biomass at the same time. This study established the estimating model of grassland yield through and the precision of the estimating model was good. The theoretical and Key Pasture carrying capacity were calculated by Key Pasture Theory. The result of this study showed that the theoretical and Key Pasture carrying capacity of Kizilsu Kirgiz Autonomous Prefecture were 1 776 100 and 1 137 100 sheep units, the overgrazing rates were 48.18% and 131.45% respectively when compared with the actual carrying capacity of 2 631 900 sheep units.