soil nutrients

Fire has been an important management tool in the pastoral use of New Zealand tussock grasslands. The effects of a farm-scale pastoral fire and subsequent grazing by sheep on soil biochemical properties in tussock grasslands dominated by the narrow-leaved snow tussock (Chionochloa rigida ssp. rigida) were investigated, 1.5 and 2.5 years after the fire event, in 0-2 cm depth mineral soil at a site at 975 m altitude in Central Otago, New Zealand. The nitrogen (N) and phosphorus (P) concentrations of C. rigida leaves were also measured.

The rate of spread of mouse-ear hawkweed (Hieracium pilosella) patches, the effect of hawkweed on soil properties, and the nutrient content of hawkweed biomass was investigated on grazed unfertilised land on Glencairn Station (altitude 440 m, mean annual rainfall 500-600 mm) in the Mackenzie basin, southern South Island, New Zealand. Pallic soils (Typic Ustochrepts) under hawkweed patches and under surrounding herbfield were analysed for exchangeable cations, organic C and total N. Total nutrients in hawkweed and herbfield biomass were measured.

The heathland vegetation of northern New Zealand is usually regarded as a "derived" vegetation type resulting from forest destruction during the Maori and European periods of settlement. Plant species cover-abundance data from sample quadrats in the Far North are analysed using Detrended Correspondence Analysis (DCA) and Two-way Indicator Species Analysis (TWINSPAN) and are then correlated with soil nutrient data. Variations in species composition of heaths appear to be related primarily to soil type. Age since last fire is also important but was not examined in detail in this study.

Litterfall reflects forest productivity and is an important pathway of nutrient cycling in forests. We quantified litter quantity, nutrient concentrations, and decomposability for 22 permanently marked plots that included gradients of altitude (a range of 320–780 m), soil nutrients and past disturbance in a cool temperate evergreen montane rain forest in the western South Island of New Zealand.