Effect of grazing intensity on subsequent regrowth of a Lolium perenne sward | The effect of grazing intensity on subsequent regrowth of a Lolium perenne sward
1977
Nicholson, M. J. L. | Hodgson, John
Perennial ryegrass swards were grazed differentially by sheep by means of constant sheep number per plot but varying plot size in order to alter herbage allowance per animal. Following two 12-day grazing periods, one in mid-summer and one in early autumn, the sheep were removed and subsequent regrowth studied for four weeks after defoliation. Growth was described in terms of biomass (standing crop), extended sward height, morphological composition and changes in the structure. Differences in regrowth were attributable to the only variable, herbage allowance, which dictated grazing intensity. Severe defoliation resulted in a smaller standing crop biomass after four weeks and a lower extended sward height. However, total leaf extension was not dependent on allowance and since tillering rate and rate of green leaf production was greatest following highest grazing intensity, it is concluded that it is more beneficial to defoliate a sward intensively in order to discourage a build up of senescent material and that no harm is detected in the short term, provided the sward is not physically damaged.
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