Dunbar: Sowing Native Tussock Species in High Altitude Vegetation Trials

Although a cover of grasses and legumes may be established on exposed mountain subsoils through seeding and the use of a complete fertiliser, this cover is not likely to last for more than a few years without the application of more fertiliser. Native tussock species once established in the protection of other low-growing species might persist and provide stability over a longer period. This paper describes the early results achieved on two sites in the Canterbury mountains, through sowing seed of four tussock species under five cover treatments. Sowing of seed of Notodanthonia setifolia produced very few seedlings but blue tussock, hard tussock and Gilver tussock gave reasonable results. Highest emergence was recorded under the least cover on the control plots, and there was, in general, an inverse relationship between cover treatment density and emergence of tussock seedlings. Survival of tussc<~k seedlings over the first eighteen months from sowing was, hQwever, in direct positive proportion to the amount of cover present. Growth of tussock seedlings was slow at both trial sites. Tiller numbers tended to be greatest in pIe.ts with least competition from cover species. Tussocks remaining amongst cover after the first winter tended to decrease in size and vigour over the second growing season.