A study of the influence of aspect on the nutrient requirements and soil chemistry of a selection of Hurunui steepland soils in South Canterbury

Abstract

Soils belonging to the Hurunui steepland set are extensively distributed along the foothills and lower slopes of the Eastern Ranges in the central and northern portions of the South Island, east of the main divide (Soil Bureau Staff, 1968). Because of their geographical position these soils enjoy relatively mild temperatures together with a reliable rainfall of 30 to 45 in. (762 to 1143 mm.) per annum. The favourable climate combined with their medium natural fertility and widespread distribution have made these soils one of the most economically important steepland soils in the South Island with significant production potential for pastoral or forestry use.

The Field Research Section of the Department of Agriculture recognised this potential and initiated a research programme on Hurunui soils in 1967 with the ultimate aim of establishing a Stocking Rate by Fertiliser Rate trial on a representative site (Gregg, 1970). The aim of this study was to extend the trial work of the Department of Agriculture into representative areas of Hurunui steepland soils within South Canterbury. Within each area the specific aims of the study were: (i) to assess the nutrient requirements of oversown white clover and to find whether these nutrient requirements were influenced by differences in aspect, (ii) to determine the impact of changing aspect on some soil chemical properties at each trial locality, (iii) to establish whether field trial results were influenced by soil fertility or by other causes as well.