The establishment and early growth of cocksfoot cultivars in tussock grasslands

Abstract

There are more than ten million acres of tussock grassland used for pastoral purposes in the South Island of New Zealand, the greater portion being crown leasehold. The 1948 Land Act makes provision for the limitation of stock numbers on this land to the winter carrying capacity. An important influence upon this is the amount of palatable grass available to stock in this period of minimum growth, as little else of feed value remains once the winter frosts begin.

Soil fertility is the principal factor limiting herbage production in the region. These tussock grasslands are inherently low in nitrogen and the technique of correcting this deficiency has been to encourage legume growth and its associated nitrogen fixation. For the introduction and growth of suitable legumes the most important limitations have been the lack of sulphur, phosphate and molybdenum.

The present practices of oversowing and topdressing result in the production of clover-rich pastures and greatly increased summer production. Clover nitrogen assists the vigour of the resident grasses. Where summer grazing is required, clover invigorated swards of predominantly native and naturalized grasses have proved satisfactory but the resultant increase of grass production in winter has been disappointing. For winter and early spring production the introduction of cocksfoot and ryegrass has been recommended. Cocksfoot particularly has proved one of most successful grasses in this environment but in many areas its establishment has proved difficult.

This thesis work was initiated to study the seedling growth of six different cultivars of cocksfoot and to assess whether this had any bearing on their establishment under field condition. Early seedling growth was compared in glasshouse and growth cabinet experiments, and the establishment of these cultivars assessed in field trials in inland Otago. Some pelleting of seed was attempted.