GORSE CONTROL WITH GOATS

Abstract

A grazing management trial in North Canterbury. compares the effects on burnt gorse, of goats or sheep grazed alone, or in mixtures with two goats equivalent to one sheep, with either rotational grazing or set stocking. Also, sheep alone are mob stocked on burnt gorse, and goats alone, set stocked on unburnt gorse. Goats alone at stocking rates up to 35/ha and a sheep/goat mixture which is rotationally grazed, have reduced gorse to negligible proportions after two years, although relatively few burnt gorse stumps have yet died. Gorse control has been less successful where a sheep/goat mixture has been set stocked or where sheep have been mob stocked at 2001ha. The least effective treatments have been sheep either set stocked or rotationally grazed at up to 17,5/ha. Stands of dense unburnt gorse up to 2m high were reduced from 66% gorse cover to 7% using 44 goats/ha set stocked for one year. Stocking rates of up to IO goats/ha had little effect on land with 50% gorse cover, but 30 goats/ha reduced gorse to 5% cover in the subsequent year. The persistence of five grass species ('Grasslands Nui' perennial ryegrass, 'Grasslands Wana' and 'Grasslands Apanui'cocksfoot, 'Massey Basyn' Yorkshire fog and browntop) and their abilities to suppress gorse, were compared under rotational and set stocked goat managements. After two years, there were no significant differences among grasses under rotational grazing, but browntop had become significantly moresuccessful than Apanui cocksfoot, under set stocking. Gorse cover was-=&% in all grass species treatments, including the unsown control plots, with no significant differences between set stocking and rotational grazing. Keywords: Gorse, goats, sheep, grazing management, ryegrass, cocksfoot, Yorkshire fog, browntop.