Effects of November–April grazing pressure on hill country pastures 1. Pasture structure and net accumulation rates

Net dry matter accumulation rates (NAR) of pasture on flat and slope areas of a steep (32° mean), NW‐facing hillside were measured during 3 years for several combinations of grazing pressure. Comparisons involved: hard and lax grazing during November‐January (pre‐dry); hard grazing and spelling during January–March (dry); and hard grazing, lax grazing, and spelling during March–April (post‐dry). Hard grazing during the pre‐dry phase reduced total pasture NAR during that period, increased total pasture and green herbage NAR during the dry phase, and reduced total pasture NAR during winter‐spring on slopes. This response was linked to better density of perennial plants, and reduced regeneration of annual populations on slopes. Spelling during the dry and post‐dry phases reduced current NAR because of senescence and decay losses. Green herbage NAR in the period immediately after spelling was also reduced. Annual pasture production was not greatly affected by short‐term grazing pressure differences, except during the first year and by post‐dry treatments. More important were the short‐term differences in NAR that influence seasonal pasture availability. January–April pasture production was encouraged by maintaining pasture density and avoiding dead herbage accumulation, and winter‐spring production was reduced on slope areas where reseeding was restricted during November–January. Practical implications are discussed.