CHEMICALS FOR PASTURE RENOVATION AND IMPROVEMENT OF HERBAGE QUALITY
Research into chemical pasture renovation was pioneered by NZ scientists in the 1960's but the technique was not widely adopted at that time. Subsequent work has confirmed that white clover (Jrifolium repens L.) is a poor competitor against browntop (Agrostis capillaris L.) for phosphate. This has implications regarding nitrogen fixation. Pasture renovation also provides an opportunity to introduce preferred pasture grasses, free of competition from resident grass species. White clover is now recognised as a high-quality feed for livestock. Work is reviewed showing the correlation between liveweight of ewe hoggets and subsequent breeding performance and that white cloverdominant pasture was superior i0 ryegrass-dominant pasture for flushing breeding ewes. In field-scale testing, the plant growth regulator mefluidide suppressed seedhead formation in pasture grasses and gave substantial, though regionally variable, liveweight gains in lambs, beef cattle and deer. In limited evaluation with dairy cows changes in pasture herbage have not been matched by improved milk or milkfat yield. Keywords: Chemical pasture renovation, fertiliser utilisation, pasture quality, chemical plant growth regulator