A study of factors influencing grasses and clover establishment and survival on native pastures dominated by Zoysia japonica was made on infertile native grassland of college livestock farm. Factors studied included: effect of herbage cover, effects of nitrogen, phosphorus and lime(slaked). The results obtained are as follows; Nitrogen and slaked lime (Ca(OH)₂) depressed significantly establishment of clover. Slaked lime depressed clover establishment was probably due to a strong alkalization of surface soil at initial stage. Lime, nitrogen and phosphorus had no significant effect on initial establishment of grasses. in both presence and absence of Zoysia japonica, but lime aided clover survival in both presence and absence of herbage cover and phosphorus aided survival of grasses in absence of cover. Dense herbage cover had little effect on clover establishment and survival, but had depressed effect on grasses establishment and survival. It is considered that failure of grasses to become established amidst dense Zoysia japonica may be attributed to competition from existing herbage cover.