Research on grassland resources yield and balance between forage resources and livestock numbers in Haidong and Haibei prefecture of Qinghai.

Observed grassland yields from areas located by GPS in Haidong and Haibei prefecture of Qinghai,were used to design natural grassland yield estimating models with vegetation index of MODIS.Estimating models for maximum theoretical livestock carrying capacity were built.Livestock carrying capacity of added forage was calculated from by-products of farming and forest.Combing the reality of seasonal pasture in Qinghai,the models for balance between carrying capacity of natural grassland or added forage and actual number of livestock were established and the current states of both prefectures were analyzed.The grassland resources yields of Haidong and Haibei prefecture were 195.30×104 and 4 590.92×104 t,respectively.Grass forage intakes were 98.41×104 and 2 306.07×104 t,and the practical usage rates of natural grasslands were 50.4% and 50.23%.The maximum livestock carrying capacity of natural grassland in both prefectures were 90.97×104 and 856.18×104 sheep units respectively.Livestock overloading in Haidong was serious,being as high as 97.9%,but in Haibei the overloading rate was-32.2%.