Estimation and change analysis of forage-livestock balance based on cold and warm season grazing region division in Yushu Prefecture, China

Yushu Prefecture, China, represents a core area of the alpine ecological barrier area in the Qinghai-Tibet Plateau, which combines agriculture and animal husbandry. The forage-livestock balance relates to the safety of ecological barrier and plays an important role in scientific economic management of animal husbandry. Therefore, we explored the changes in forage-livestock balance in the natural grassland of Yushu Prefecture, China, between 2014－2019. The MOD13A1 NDVI and MOD17A3H NPP product, statistical data, and vegetation type data were mainly used. This study considered the grazing region in cold and warm seasons in each county of Yushu Prefecture according to rotation grazing practices. The reasonable carrying capacity of natural grassland in each county was determined using "barrel effect" and the forage-livestock balance was evaluated. According to the theoretical law of natural rotation grazing, the cold season grazing region was located in the warm valley region, while the warm season grazing region was located in the alpine region, based on fixed area proportion and spatio-temporal NDVI distribution. The cold-season grazing region hay fields were bigger than that of the warm-season grazing region. Hay yields exhibited a fluctuating increasing trend in both cold and warm season grazing regions between 2014－2019. The average annual hay growth rate was > 3.00% in each county, of which the growth rate in the warm season grazing region was higher than that in cold season grazing region. Between 2014－2019, the forage-livestock balance in Yushu Prefecture gradually fluctuated from critical overload or overload to equilibrium; however, forage-livestock balances differed among counties, which might be attributable to the difference in the spatial scope of ecological engineering support between nature reserves and national parks. Our findings contribute to formulating construction plans for Sanjiangyuan Nature Reserves, National Parks, and realizing the benign development of the park’s ecology and animal husbandry economy.