Management of lucerne overdrilled with ‘Grasslands Tama’ Westerwolds ryegrass, on irrigated Wakanui silt loam

Abstract

Cutting and grazing treatments affecting the establishment of overdrilled ‘Grasslands Tama’ Westerwolds ryegrass in established ‘Wairau’ lucerne, and the competition between established Tama ryegrass and lucerne resuming growth in early spring, were studied in three experiments. Delaying defoliation after overdrilling Tama in mid March to 8 weeks rather than 4 weeks reduced yield of Tama ryegrass by 40% at the next defoliation in early spring. Competition between Tama ryegrass and lucerne with time of late-winter-early-spring defoliation was variable. In the cutting experiment (30 August and 4 October treatments) and in one of the grazing experiments (4 September and 24 September treatments), ultimate lucerne yields in summer were similar for both treatments. In the other grazing experiment, there was poor regrowth of lucerne after grazing under wet conditions on 12 August and 26 August and also when grazing was delayed to 23 September, but grazing on 9 September gave a satisfactory subsequent change from Tama ryegrass to lucerne.