Pasture growth and quality on West Coast dairy farms

Abstract

Variation in rainfall, soil type and growing degree days across the West Coast creates wide variation in pasture growth rates. Farmers require pasture growth rate and quality information local to their environment to assist them with their on-farm decision making. Four farms in different geographical regions of the South Island's West Coast were monitored for four years to measure pasture growth rate (weekly, plate meter), nutrient composition (fortnightly, pre-grazing) and soil temperature (weekly, 10 cm depth). Average monthly pasture growth rate varied between the farms, however the seasonal trends were similar in all regions. There was significant variation in average monthly growth rate between years for individual farms. Soil temperature explained some of the trends in pasture growth rate, particularly in winter and early spring. Pasture quality was lowest during the summer months when neutral detergent fibre concentrations were greater. Pasture crude protein concentration exceeded 25% in 63% of the samples collected. Information reported will allow dairy farmers and their advisors to develop feed budgets and assess the appropriateness of the stocking rate and calving date of the farm relative to the annual pasture growth patterns. Times of year when the greatest variability occurs have now been identified for each sub-region. Keywords: West Coast, pasture growth, pasture quality, dairy