Lucerne (Medicago sativaL) establishment on uncultivated pumice hill country

Abstract

The establishment of luceme oversown into herbicide-treated pasture on steep hill country in the central North Island was investigated in 4 trials. Netting increased establishment and this was probably a result of protection of seeds and seedlings from predation. Trampling seed by stock after sowing improved plant establishment where nets were not used. Trampling seed after sowing was also beneficial where nets were used to control predation but the increased length of cover had a negative effect. Sowings from mi.d-July o~wards gave the most effective plant establishment; lime or seed pelleting generally improved plant establishment with seed pelleting replacing the need for Iime. Overall, however, luceme establishment by oversowing still cannot be achieved with complete reliability.

Effect of treading, herbicides, season, and seed coating on oversown grass and legume establishment in easy North Island hill country

“…At 8 weeks, % seedling survival was highest in the paraquat and glyphosate treatments where pasture regrowth was still negligible, intermediate in the maleic hydrazide treated swards where appreciable regrowth had occurred, and negligible in the untreated swards where there was considerable regrowth. These results extend and confirm the conclusions drawn from earlier studies that paraquat treatment of dense resident vegetation considerably improved the establishment and survival of oversown species through the creation of a dead, non-competitive ground cover (O'Connor 1963;Blackmore 1964;Cullen 1966Cullen , 1969Janson & White 1971;Baars et al 1982).…”

“…Although herbicide application -in reducing competition to the establishing seedling (Blackmore 1964) -and the treading in of oversown seed (Sewell 1950;Baars et al 1982) have been recognised as desirable, little has been done to quantify the results of these treatments.…”

The production and utilization of lucerne in New Zealand

“…On the other hand, in semi-arid environments closing land from grazing can be advantageous to lucerne establishment by improving cover (Musgrave, 1976). Cover also provides some protection from bird predation (Baars et al, 1982) but it may increase the damage from slugs (Campbell and Swain, 1973b). In Australia, ants can take a significant proportion of oversown seed (Campbell and Swain, 1973b).…”

Pasture establishment on non-cultivable hill country: a review of the New Zealand literature

“…Note also that herbicide residual activity sometimes has detrimental effects on establishing seedlings (e.g. Baars et al 1982) -timing of application is therefore critical.…”

“…Litter (dead matter) cover can assist germination by modifying the microclimate by reducing temperature extremes, increasing relative humidity and creating a soil surface that is more amenable for germination, as well as reducing seed predation Campbell & Swain 1973;Baars et al 1982). For example, Chapman & Fletcher (1985) found that seedling mortality was greatest where resident vegetation had been suppressed the most; up to 20% of seedlings died within 3 weeks of appearance in glyphosate-treated plots.…”