The effects of lime on pasture composition and production in western Waikato hill country

A 4-year lime rate trial was established on a hill country sheep and cattle property near Te Akau to determine lime effects on pasture utilisation. Four rates of lime were applied (1.25 t/ha, 2.5 t/ha, 5 t/ha and 10 t/ha) to 2 m × 2 m plots, from which soil Al, Ca and pH, pasture grazing heights, dry matter production, pasture species composition, feed quality and brix levels were measured. Lime application reduced soil Al (14.6 to 1.1 mg/kg), and increased Ca and pH (5.0 to 6.2) over time in the highest application rate. Dry matter production responded to all rates of lime in each year, and by the fourth year it was 27% greater (1.25 t/ha treatment), 35% greater (2.5 t/ha treatment), 69% greater (5 t/ha treatment), and 97% greater (10 t/ha treatment) than in the un-limed plots. Ryegrass and subterranean clover content increased with lime rate, whereas chewings fescue and dicot weed content declined. There were no sustained differences in pasture grazing heights, feed quality or brix levels between the control and rates of lime. On this site, all rates of lime were economic to apply by truck or plane when the benefits were spread over 4 years, with the greatest cost-benefit from thelower rates of lime.