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

Abstract

The influence of six pre-sowing herbicide treatments (no spray, two rates of glyphosate, and three rates of paraquat) on oversowing success of three species (,Grasslands Wana' cocksfoot, 'Grasslands Maru' phalaris, and 'Grasslands Tahora' white clover) were compared in autumn at two southern Hawke's Bay hill country sites (Ballantrae and Dannevirke) and in two seasons (spring and autumn) at the Ballantrae site. Pasture suppression by herbicide was compared using point analysis. Initial results from oversowing were compared by regular counts of seedling appearance and long -term results were determined from the contribution of introduced species to total herbage accumulation (RA) during the following 3-4 years. Paraquat and glyphosate were similar, at equal rates of active ingredient, for the establishment and performance of Wana or Maru, and were best at the highest rate of 0.7-0.8 kg a.i./ha. The contribution of Wana increased over 3 years under continuous sheep grazing to be 13-27% of total RA depending on the site, year, and herbicide combination, and was maintained during a fourth year. Wana did not significantly increase seasonal or annual total HA. Maru failed to establish and produce successfully. The establishment of Wana and Tahora was significantly and linearly related to rainfall in the first week and first 2 weeks respectively, following sowing, but unrelated to rain before sowing or 3 weeks after sowing. Spring oversowing atBallantrae was unsuccessful.

Review: World checklist of white clover varieties II

“…Responds to added P by increasing leaf number and stolon length to a much greater extent than KOPU (Mackay & Caradus 1988). Relatively unaffected by paraquat and glyphosate (Barker et al 1988). Less salt-tolerant than HAIFA and IRRIGATION (Clark 1991a).…”

Direct seeding of indigenous tree and shrub species into New Zealand hill country pasture

“…With the exception of suppression of resident vegetation (not tested in this study), all of these factors appeared to influence the outcome of this study and are discussed systematically in the following sections. The effect of resident vegetation suppression is already well recognized as a critical step in establishing new species (Barker et al . 1988; Stevenson & Smale 2005).…”

“…Significant research has been undertaken in New Zealand hill country in this respect, and a fairly standard approach has been developed (Sithamparanathan et al . 1986; Barker et al . 1988).…”

Effects of cultivar introduction and fertiliser on characteristics of white clover (Trifolium repensL.) plants and populations in a hill pasture

“…Although herbicide pre-treatment of the existing pasture was used here to aid establishment, this is not a prerequisite for successful cultivar introduction. Several experiments in hill country have shown similar rates of white clover seed germination and seedling establishment following oversowing into unsprayed and sprayed pasture (e.g., Chapman & Fletcher 1985;Barker et al 1988), though seedlings usually develop and spread more rapidly when herbicide is used (Chapman & Fletcher 1985). Provided careful attention is paid to seedbed preparation, timing of sowing, and post-sowing management (Lambert et al 1985), white clover cultivar introduction can be a successful and relatively low-cost operation which yields annual returns for an initial one-off investment.…”