What are the best pasture improvement options for different South Island hill and high-country environments?

Abstract

A range of options exist to improve pasture in the South Island hill and high country. Pasture yield and the cost of seed, lime and fertiliser from 55 trial sites were used to calculate partial gross margins (GM) for a range of improvements on different slopes and aspects. On drillable land, for average rainfall <500 mm/yr, pastures should be based on subterranean clover or perennial lupins. Lucerne can be used where root growth is not limited by soil depth. At 500-750 mm/yr rainfall, lucerne and perennial lupins, with subterranean or Caucasian clover, are viable. Where rainfall is >750 mm, lucerne and Caucasian, white and red clover can be sown. At similar rainfall, soil moisture is more limited on non-drillable hill compared with drillable land, and aspect must be considered. At <750 mm/yr on sunny aspects, clover, e.g., subterranean or balansa,
are the best options, and shady areas can be improved with subterranean clover. Late winter application of 30- 50 kg/ha nitrogen can be used on shady aspects with less than 750 /yr rainfall or sunny aspects with higher rainfall. For >750 mm/yr rainfall on shady aspects, pasture should be managed to maximise legume content, and over-sowing white clover should be considered.