Successful Pasture Establishment in Central Otago

New Zealand Journal of Agriculture, Volume 95, Issue 6, 16 December 1957, Page 545

Successful Pasture Establishment in Central Otago

By

R. C. SCHOFIELD,

Instructor in Agriculture, Department of Agriculture, Alexandra

THERE are thousands of acres of partially improved and unimproved country in Central Otago on which production could profitably be increased. Development of much of this country, which is virtually denuded of vegetation, depends basically on building up fertility to a stage where the land will support an improved pasture. The growing of greenfeed, fertilised with superphosphate, and its grazing by stock during both autumn and spring have brought about considerable improvement, to an extent that successful pasture establishment is assured.

FEW plants or associations of plants are capable of relatively high production on this denuded country. Therefore, to see if advantage could be taken of the increased fertility and to determine the plant species capable of reasonable production and of withstanding drought and severe winter conditions, an investigation was carried out in the Dublin Bay district, near Wanaka. The soil, which is a sandy loam with shingle outcrops overlying gravels, is somewhat similar to many Central Otago soils. The result of this investigation would have a very wide application throughout Central Otago, which is subject to winds from all quarters and is extremely dry during summer.

The basis of the investigation was the introduction of a suitable legume. At the same time the possibilities of various grasses were considered. The legumes selected and their rate of sowing were lucerne 121 b. per acre, Montgomery red clover 31b., white clover 31b., subterranean clover 41b., and sweet clover 41b. Cocksfoot 31b., Phalaris tuberosa 31b., tall oat grass 101 b., tall fescue 101 b., and meadow fescue 101 b. were the grasses chosen.

They were sown in various combinations with the legumes. As a comparison a mixture was sown containing perennial ryegrass 101 b., short-rotation ryegrass 51b., cocksfoot 41b., white clover 21b., Montgomery red clover 21b., and subterranean clover 41b., a total of 271 b. of seed an acre. The trial was sown on 1 October 1953 with 2cwt. of superphosphate per acre and observations were continued for three seasons. The result of this investigation showed that of the grasses cocksfoot was vastly superior. Its ability to produce under the drier conditions, to respond to the limited rainfall, and to recover after drought make it the most suitable grass available. Phalaris tuberosa, though suitable in the dry

periods, did not produce as well or recover as soon as cocksfoot. The ryegrasses and meadow fescue failed miserably. Tall oat grass proved to be a relatively low producing plant of questionable palatability. It was slow to establish and slow to recover after drought. It could have greater use on less fertile and inaccessible country. Tall fescue was extremely slow to develop and after three seasons was just beginning to show up.

Of the legumes subterranean clover was established successfully in spring and, provided critically dry conditions do not exist at seed setting, it will continue seasonally, but this is always doubtful in this climate. Montgomery red clover and white clover established readily, but there was a considerable mortality of plants each year, thus reducing the ability of this species to maintain itself under the normal dry conditions.

Lucerne is unquestionably the best of the legumes. It is the first to show growth in spring and the first to recover in autumn. With cocksfoot it formed the superior association over the whole period observed. In the early stages cocksfoot showed dominance, but this dominance was reversed in the second season, and by the third season a satisfactory relationship between these plants was achieved.

This investigation indicates that after the feeding off of greenfeed crops sown with superphosphate to improve the fertility, pasture can be established successfully, and that the best seeds mixture is lucerne at 81b. to 101 b. and cocksfoot at 31b. with 2cwt. of superphosphate per acre. The result of this trial is a worthwhile increase in feed production and carrying capacity, and the practices adopted could be applied on thousands of acres of Central Otago.