The Effects of Cutting and Grazing Systems on Herbage Production From Grass Swards

Abstract

Studies were made on two perennial ryegrassdominant swards of the effects of cutting and grazing systems ou herbage production. A motor scythe was used for cutting and sheep in small enclosures for grazing. In both systems, herbage production was measured hy a ground-level sampling technique, using sheep shears, and the difference between pre-treatment and post-treatment herbage was expressed as 'utilized yield'. Correction for soil contamination is ensured by quoting all results on an organic-matter basis.Grazing treatments averaged 14-16% more organic matter and 36-45% more crude protein than cutting treatments in both experiments. These differences were ascribed to recycling of N under grazing. Infrequent defoliation gave higher yields than frequent, and severe defoliation higher yields than lenient under both cutting and grazing systems. The trends shown by cutting and grazing intensities are comparable and can be quantified.There is need to examine closely the relationships between the effects of cutting and grazing techniques on herbage production, since such knowledge would allow a more accurate prediction of the relevance to the grazing situation of results obtained under cutting.

Effects of cutting regime on pasture production

“…Also, if the pasture is cut to 3 em at each cutting DM production is greater than when it is cut to 6 em. These results agree with those from several cutting experiments with mixed grass-clover pastures (Reid 1959;Frame & Hunt 1971;Appadurai & Holmes 1964), but disagree with the results of Brougham (1959) and Weeda (1965). Brougham (1959) showed that there was more DM production from lax defoliation (e.g., grazed to 8 em compared with 3 em) when pastures were frequently grazed.…”

“…Several experiments, designed to simulate rotational grazing systems, have demonstrated that the frequency and severity of grazing can affect pasture production. Infrequent defoliation can be expected to improve dry matter (D M) production over frequent defoliation (Frame 1966;Anslow 1967), and close defoliation produces more DM than lax defoliation (Frame & Hunt 1971). In practice many rotational grazing systems, especially on dairy farms, have a rotation based on a fixed regrowth period between grazings.…”

Growth factors and management technique used in relation to the developmental rhythm and yield formation pattern of a pure grass stand

“…The dependence between cellulase and in vitro digestibility determined for fescue corresponds well to correlations for clovergrass mixture and coach grass (Pulli 1976). (Carter and Law 1948, Huokuna 1957, Brougham 1959, Heinrichs and Crark 1961, Laine 1965, Anslow 1967, Frame and Hunt 1971, Pedersen et al 1974, Wolton 1976.…”

Micro-patterns in grassland vegetation created and sustained by sheep-grazing

“…The sheep preference for recently burnt heathland areas was correlated with a high N content of heather leaves (Grant & Hunter, 1968). Frame & Hunt (1971) found that in grass swards the frequently defoliated herbage had a higher percentage of crude protein than that of other treatments. Btirkle (1980) found more crude protein when the remainder was mown than in the part not cut of a continuously grazed area.…”