The direct and residual effects of the fertilisation of a grass/clover pasture

Abstract

The results of a factoral experiment in which various fertiliser treatments were applied to a mixed Paspulum dilatatum and N.Z. wild white clover pasture have indicated that under conditions of complete crop removal, highly significant responses to the application of nitrogen, phosphate and potash can be experienced. The results have also indicated that the response of the pasture to phosphate applications depends on the type of phosphate used and whether it is applied as a basal treatment or as annual top-dressings. Although these mean effects were of significance when the total production of herbage over five years was statistically analysed, the analysis of the seasonal yields indicated that the significance of the treatments declined with the passage of time. The results obtained from maize crops which followed the pasture phase of the experiment indicated that the application of fertiliser to the pasture was inadequate in meeting the demands of the pasture crop with the result that the plant nutrient resources of the soil were severely depleted. It was shown, however, that the productivity of the soil could be restored by the application of adequate quantities of fertiliser.

Keywords: basal areas|herbage production|yields|plant nutrients|soil nutrients|Natal|seasonal yields|East Griqualand|grasses|maize|fertilisation|clovers|potash|pastures|fertilisers|nitrogen|phosphate|treatments