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- Title
AN ASSESSMENT OF THE ROLE OF PLANTING DENSITY IN COMPETITION BETWEEN RED CLOVER (TRIFOLIUM PRATENSE L.) AND LUCERNE (MEDICAGO SATIVA L.) IN THE EARLY VEGETATIVE STAGE.
- Authors
Black, J. N.
- Abstract
An experiment was conducted at the Royal Agricultural College, Uppsala, Sweden, in which competition between red clover (Trifolium pratense L.) and lucerne (Medicago sativa L.) was studied at a range of planting densities. Both species were grown in pure swards at eight densities, ranging from 50 to 12,500 plants/m², in order to establish yield : density relationships. Sixteen mixed swards were grown, comprising all combinations of the four following densities :—50,250, 1250 and 6250 plants/m². Plant numbers and dry weights of above ground material were obtained on two occasions in the early vegetative stage. The data for the pure stands showed that the maximum yield of lucerne was half and two-thirds that of the clover at the 1st and 2nd harvest occasions respectively, and that this maximum yield was reached at a lesser plant density in lucerne than in clover. Furthermore, seedling mortality was much higher in lucerne than in clover. It was therefore not surprising to find that, in the mixtures, clover suppressed lucerne at all but the lowest densities. From the pure sward data it was possible to calculate the expected weight of the two components of any mixture, on the assumption that interspecific competition was not operative, thus eliminating the yield differences due to specific differences in the yield : density relationships at the two occasions. Any difference between these calculated expected weights and the actual measured weights would therefore be due to interspecific competition. From this analysis it is postulated that the growth of one species was depressed when that species was present at high densities, with the other present at low densities, and was increased when that species was present at low densities and the other at high densities. This is considered to be a restatement of Clements. Weaver and Hanson's proposition that competition is keenest when the species are most similar.
- Subjects
SWEDEN; RED clover; FEASIBILITY studies; ALFALFA; LEGUMES; UNIVERSITIES &; colleges; COMPETITION (Biology); AGRICULTURE
- Publication
Oikos, 1960, Vol 11, Issue 1, p26
- ISSN
0030-1299
- Publication type
Article
- DOI
10.2307/3564882