Interspecific competition and co-existence in permanent grasses+Trifolium repens mixed pasture in Karst region

Asymmetrical competitions play an actual role in population co-existence of permanent mixed pasture. Perturbation experiments was conducted on 20yr old binary mixed pasture, which composed of white clover with cocksfoot/red fescue, to study the mechanism of coexisted population. The net production of white clover increased after removal of company grass at both mixtures which suggested that company grass had a competitive effect on white clover. The competitive intensity varied in different seasons, with a low value at beginning of growing season and a high value at the late stage. However, company grass responded differently which decreased after the removal of white clover with the intensity values between -0.023～-0.394 and suggested that nutricism benefits exceeded competitive effects from white clover. In the current system with moderate grazing, asymmetrical competitions is very important for all components dynamically balanced over a long term.