Pasture growth and quality on Southland and Otago dairy farms

Abstract

There is debate on how pasture growth rates and annual production on dairy farms in Southland/Otago compare to the comprehensive data collected at AgResearch Woodlands under sheep grazing. Additionally, there are no good data on seasonal variation in dairy pasture quality from the region. Six farms in different geographical regions of Southland and south and west Otago were monitored from spring 2007 until May 2012 to measure pasture growth rate, soil temperature and pasture nutrient composition (with the exception of south Otago). Pasture growth rates varied between farms and between years. The highest growth rates were recorded in coastal Southland and the lowest in northern Southland. Rainfall and soil temperature differences explained some of the changes in pasture growth rate throughout the seasons. Sharp drops in pasture quality in early summer were recorded on all farms. Considerable variation in pasture growth rate occurs across the Southland/Otago regions. Times of year when the greatest variability occurs have now been identified for each region. Keywords: Southland, Otago, pasture growth, pasture quality, dairy