Seasonal distribution of pasture production in New Zealand XVIV. Central Taranaki

Abstract

Pasture growth rates for 8 years are presented for a Stratford site, at an altitude of 311 m on the eastern ring-plain surrounding Mt Egmont. Yields were measured on grazed pasture cut with a standardised method using moveable cages. The mean yield and standard deviation over all years of measurement are given for the 2 standard cutting intervals — 14 and 28 days. The growth pattern for both cutting intervals had a spring peak, although the spring growth rates were lower but persisted longer under 14 day cutting than for 28 day cutting, and a marked winter depression occurred from June to August. The mean annual yield was 12 030 kg DM/ha under 28 day cutting, and 9 940 kg DM/ha under 14 day cutting. On average, 41 and 36% of the annual yield was produced in the spring months for 28 and 14 day cutting intervals respectively, 31 and 32% was produced in summer months and 19 and 23% over autumn. In winter, 9% of the annual yield was grown at both cutting intervals. The onset of spring growth and maximum growth rate attained showed marked variation between years. This affects decision-making for both calving date and paddock closure for conservation. Late summer/early autumn growth rates also varied markedly reflecting the variable summer rainfall and soil moisture. The growth pattern of the Lolium perenne component was similar to that of the entire sward, reaching a peak in October/November, while Trifolium repens did not reach peak growth until December/January. General climatological data, rainfall, and mean air temperature during the period of pasture measurement are given.

Keywords:

• pasture production
• ryegrass
• white clover
• seasonal distribution
• soil moisture