Cutting effects on growth characteristics, yield composition, and population relationships of perennial ryegrass and white clover in mixed pasture

Abstract To research the effects of cutting on growth characteristics, yield, proportion composition, and the population relationships of perennial ryegrass ( Lolium perenne ) and white clover ( Trifolium repens ) in mixtures, the number of tillers and leaf growth of perennial ryegrass, number of branches and stolon growth of white clover, and herbage yields and the proportion of each component in total yields were measured under different cutting systems (i.e., simulated grazing) in 1998 and 1999. The results showed that increased cutting frequency inhibited tillering of ryegrass, stimulated ryegrass leaf growth and clover branching, reduced death of ryegrass leaves and clover branches, and maintained proportions of perennial ryegrass and white clover in the mixed pasture. Cutting frequency had no significant effects on herbage yields or vegetative composition ( P > 0.05). As the cutting frequencies decreased, the population relationships of the two species transformed from mutual promotion to inhibition. Higher cutting frequencies promoted a positive interaction between ryegrass and clover. Thus, cutting decreased the inhibitory effects of these two species on each other.