The influence of Nitrogen on seedling and early growth of perennial ryegrass and Cocksfoot

Summary The growth of seedlings of perennial ryegrass ( Lolium perenne L.) and cocksfoot ( Dactylis glomerata L.) was studied at different soil nitrogen levels. At all nitrogen levels, and at all stages of growth studied, perennial ryegrass seedlings produced more dry matter than cocksfoot. After the initial two‐weeks period, the dry‐matter production ratio of perennial ryegrass to cocksfoot was greater at the lower levels of nitrogen than at the higher. At high nitrogen levels the relative growth rates of the two species were similar, but at lower nitrogen levels the relative growth rate of perennial ryegrass was significantly greater than that of cocksfoot in the second two weeks of growth, and significantly less than that of cocksfoot in the fourth two weeks of growth. The results are discussed in relation to early competition as affected by soil nitrogen, light, and temperature, between these two species in pasture mixtures.