Factors affecting the performance of seedlings and ramets of invading grasses in an established ryegrass sward.
Seedlings and 2-tiller ramets of Poa trivialis, P. annua, Agrostis stolonifera and Festuca rubra were planted into an established sward of Lolium perenne in spring and autumn 1976 and 1977. Seedling survival after 1 year or 18 months varied from 0.4 to 38.5%. Fertilizer N and spring sowing reduced survival in F. rubra and P. trivialis but not in A. stolonifera or P. annua. Seedling mortality was greatest in P. annua and least in F. rubra. Ramet survival at final harvest varied from 21 to 95%, being greatest in P. trivialis and least in P. annua; it was greater among autumn planted ramets, especially in P. annua. Autumn planting and N application increased ramet weight, while PK fertilizer application decreased it. Differences between spp. in plant survival and plant size are discussed in relation to changes in the botanical composition of sown swards with age and management.