A study on below-ground biomass and net primary production of sub-alpine meadow in Northwest Yunnan Province

Below-ground biomass and net primary production were investigated in three used types communal grassland: grazing pasture,forage grassland,cultivated grassland in a tibetan village,Dala,Shangri-la county in Northwest Yunnan Province.The comparative studies were explicated from temporal variation and vertical distribution.Study results suggest that the temporal variation of below-ground biomass of three grasslands all represent two peak value,and the vertical distribution represent T model.The sequence of net primary production is forage grassland,cultivated grassland,grazing pasture.Perennial grazing reduce the below-ground biomass and mostly distribution in surface layer,at the same time,production is also reduced.A thorough cultivation can decrease below-ground biomass obviously,but accelerate the turnover rate of roots and also advance the production.The traditional forage grassland maintains the below-ground biomass and production well,benefiting the resuscitation of meadows.