Publication Date
1989
Location
Nice France
Description
Pasture grazing managements have clearly identifiable effects on plant morphology, density and species composition. Typically, swards grazed continuously by sheep have relatively high populations of relatively small perennial ryegrass tillers while rotationally grazed swards contain rather fewer large/ tillers (Chapman and Clark 1984, Suckling 1959, Mitchelle and Glenday 1958, Collet et al., 1981). Generally, more severe defoliations are associated with greater tiller densities (Davies 1977). Management induced increases in tiller populations of perennial pastures are possible because plants tiller freely when competition for light is reduced by herbage removal (Hunt and Field 1978). If left undisturbed, tiller density is finally determined by self-thinning and tiller size in accordance with the 3/2 power law (Kays and Harper 1974). Where intense competition for light does occur, such as in infrequently defoliated swards in spring (Ong 1978b), reductions in population density are achieved at the expense of the smallest tillers, they being the first to die (Ong 1978a). Studies of the interaction between grazing management and tiller dynamics, must focus on differences in rates of tiller production and loss as the initial cause of divergence in tiller density. Parsons et al. (1984) suggest higher tiller densities occur in continuously stocked swards because the faster growing tillers w��ich could potentially eliminate their slower growing neighbours are inhibited from doing so because the faster growing tillers are the ones defoliated most frequently. This paper reports on a study in which the rates of production and loss of grass tiller and clover buds under three sheep grazing management systems was closely monitored with the objective of identify mechanisms whereby grazing management determines population density.
Citation
Hunt, W F., "Grazing Management Effects on Perennial Ryegrass and White Clover Triller Populations" (1989). IGC Proceedings (1985-2023). 22.
(URL: https://uknowledge.uky.edu/igc/1989/session9/22)
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Grazing Management Effects on Perennial Ryegrass and White Clover Triller Populations
Nice France
Pasture grazing managements have clearly identifiable effects on plant morphology, density and species composition. Typically, swards grazed continuously by sheep have relatively high populations of relatively small perennial ryegrass tillers while rotationally grazed swards contain rather fewer large/ tillers (Chapman and Clark 1984, Suckling 1959, Mitchelle and Glenday 1958, Collet et al., 1981). Generally, more severe defoliations are associated with greater tiller densities (Davies 1977). Management induced increases in tiller populations of perennial pastures are possible because plants tiller freely when competition for light is reduced by herbage removal (Hunt and Field 1978). If left undisturbed, tiller density is finally determined by self-thinning and tiller size in accordance with the 3/2 power law (Kays and Harper 1974). Where intense competition for light does occur, such as in infrequently defoliated swards in spring (Ong 1978b), reductions in population density are achieved at the expense of the smallest tillers, they being the first to die (Ong 1978a). Studies of the interaction between grazing management and tiller dynamics, must focus on differences in rates of tiller production and loss as the initial cause of divergence in tiller density. Parsons et al. (1984) suggest higher tiller densities occur in continuously stocked swards because the faster growing tillers w��ich could potentially eliminate their slower growing neighbours are inhibited from doing so because the faster growing tillers are the ones defoliated most frequently. This paper reports on a study in which the rates of production and loss of grass tiller and clover buds under three sheep grazing management systems was closely monitored with the objective of identify mechanisms whereby grazing management determines population density.
