Nutritive value of some high-country pastures

Abstract

Most of the observations and research work carried out to date on the high country of New Zealand have been concerned with the maintenance of the existing pasture cover or of regeneration in depleted areas. This line of work is obviously a most important one, but it should go hand in hand with a study of the animals grazing those pastures. This paper is concerned with an attempt to bridge the gap between the plant and the animal, by chemical analysis of the pasture to determine its value to the grazing sheep. Much work has been done on the food value of highly improved pastures of the ryegrass-clover type on the topdressable dairy and fat lamb country. Such pastures have been shown to be of exceptionally high value, being highly digestible, and containing ample protein, calcium, and phosphorus. By contrast our knowledge of the hill country is extremely limited. The only data available are Aston’s analyses on pastures from some areas in the Wairarapa and Poverty Bay, and Rigg and Askew’s survey of some hill pastures in the Nelson district, all done over 20 years ago. The most important feature of this work was the low phosphorus content of some Wairarapa pastures levels down to as low as 0.09 per cent of phosphorus in the dry summer-and this was associated with phosphorus deficiency of the stock. As far as I am aware, no chemical analyses have been reported on the pastures of the high country and the work to be described was undertaken to extend our knowledge in that direction. Our work at Lincoln has been along the following lines :- I. A preliminary survey of South Island hill country and high country pastures in regard to their chemical analysis. II. Analysis of individual species taken from Grasmere Station in the high country. III. Analysis of individual species taken from a North Canterbury Catchment Board enclosure in the high country near Lake Coleridge.