Establishment of ryegrass, cocksfoot, and white clover by oversowing in hill country 2. Sown species and total herbage accumulation

Abstract

Herbage accumulation of ryegrass, cocksfoot, white clover, and total pasture was measured during the second (1982-83) and third (1983-84) years after oversowing these species in moderate-fertility, summer-moist hili country.'Grasslands Nui' ryegrass + 'Grasslands Huia' white clover, and 'Grasslands Wana' cocksfoot + 'Grasslands Huia' white clover mixes were sown into 5 sward treatments. Unsown swards of each treatment were included as controls. Cocksfoot herbage production and proportion of sward content were high (49.3 and 33.6% of total dry matter (DM) for the respective years) in plots sprayed with herbicide before sowing, but negligible in unsprayed swards. Ryegrass herbage production and proportion ofsward content were also high (45.0% oftotal DM) in all treatments, except lax grazing, during 1982-83. Important differences in species persistence occurred -sown ryegrass largely disappeared early in the third year after sowing, whereas cocksfoot persisted reasonably weil. Sowing cocksfoot or ryegrass did not increase annual or seasonal pasture production above unsown sward levels, irrespective of pre-sowing sward treatment. The value of introducing new grass cultivars into summermoist hilI country at moderate levels of fertility is therefore questionable, though further data are required to fully assess the impact on hilI farm productivity.

Oversowing ‘Grasslands Wana’ cocksfoot, ‘Grasslands Maru’ phalaris, and ‘Grasslands Tahora’ white clover in hill country at varying rates of paraquat and glyphosate

“…It is likely the close defoliation under continuous sheep grazing in this series reduced the competitive ability of Wana from that observed under rotational (on/ oft) grazing reported in previous work (Barker et al 1985;Chapman & Campbell 1986). The 3-4-year persistence of Wan a under continuous sheep grazing nevertheless supports the expectation that Wana may be more persistent under severe grazing than 'Grasslands Apanui' cocksfoot because of its dense and prostrate habit (Rumball 1982).…”

“…Wana cocksfoot was established from autumn oversowing to average 13-27% of total annual HA in four trials after 3 years from sowing, and these levels were maintained during a fourth year of measurement These improvements over a 3-year period in establishing Wana agree with previous observations (Barker et al 1985); however, the final levels achieved are considerably lower than previously reported levels of 34-49% Campbell 1986) and45-76% (Barkeretal.1985). It is likely the close defoliation under continuous sheep grazing in this series reduced the competitive ability of Wana from that observed under rotational (on/ oft) grazing reported in previous work (Barker et al 1985;Chapman & Campbell 1986).…”

Evaluation of clovers in dry hill country 9. White clover at “Ballantrae”, and in central Wairarapa, New Zealand

“…'Grasslands Huia' in the Ballantrae experiment produced considerably more DM than in the trials of Lambertet al (1986)and Chapman & Campbell (1986), also at Ballantrae, where it was oversown into pastures receiving high fertiliser inputs by comparison to this trial. Lambert et al (1986) recorded average total white clover yields ('GrasslandsHuia' plustheresidentgenotype) under sheep grazing of about 1150 kg DM/ha per year over 6 years when57 kg ofP was appliedper ha per year, and 500-550 kg DM/ha per year when only 11kg P was appliedper ha per year.…”

Allozyme markers suitable for pasture persistence studies in cocksfoot (Dactylis glomerata) cv. Grasslands Wana

“…Cocksfoot in general is not a significant component of hill country pastures, and any increase in cocksfoot content of a pasture following oversowing could be easily recorded by direct observation (as in Barker et al 1985;Chapman & Campbell 1986;Webby et al 1990;Barker et al 1991). However, the use of genetic markers to follow the establishment and persistence of oversown 'Grasslands Wana' will be necessary where pastures into which it is oversown already contain a significant population of previously introduced cocksfoot.…”