The relationships between community biomass and soil nutrients in the northern Tibet degradation grassland

Grassland degradation had characteristic of vegetation and soil degradation synchronization. In order to study the relationships between community biomass and soil nutrient during degradation processes in the northern Tibet grassland, alpine grassland in Nagqu, northern Tibet with different degraded degrees were selected to study the variations of soil nutrients and above ground biomass. The results showed that with increasing of grassland degradation, aboveground biomass and soil organic matter significantly decreased. Total nitrogen, total phosphorus and total potassium had significant positive correlation with soil organic matter (P<0.05) whereas soil pH had significant negative correlation with soil organic matter content (P<0.05). Aboveground biomass had significant positive correlation with soil organic matter content (P<0.05) but had no correlation with total nitrogen, total phosphorus, total potassium and pH (P>0.05).