COMPETITION BETWEEN LOLIUM-PERENNE AND POA-TRIVIALIS DURING ESTABLISHMENT

Three experiments were carried out in boxes to determine the response of L. perenne seedlings to competition from P. trivialis seedlings at different densities and ages and when the proportions of the two species were varied according to the replacement principle. Tiller numbers per plant were significantly reduced by P. trivialis at densities commonly found in the field. Prior establishment of P. trivialis caused disproportionate damage to L perenne tillering and the early removal of such plants resulted in yield benefits to L. perenne. When sown together, P. trivialis was shown to be competitive towards L. perenne during the first 4 weeks of establishment but during the next 4 weeks, although competition was still occurring between the two species to the detriment of Poa, relative productivity (but not total productivity) was marginally greater in the mixture. The need for early herbicide treatment to prevent interspecific competition between graminaceous species during establishment is discussed. Copyright © 1979, Wiley Blackwell. All rights reserved