Long term nitrogen application to veld in South Africa

Abstract

The most important results of thirteen fertilizer experiments on veld, extending over periods of five to twenty years, are dealt with. In general, with nitrogen fertilisation climax grasses were replaced by grasses of a more pioneer type. Of the nitrogenous ferlilisers used, ammonium sulphate maintained the best basal cover (urea not considered) and produced the greatest yield response (urea included). Compared with ammonium nitrate, sodium nitrate and urea, it also displaced the climax grasses most rapidly, whilst urea had the slowest displacement effect. Above approximately 150 pounds nitrogen per morgen p.a., urea gave the lowest hay yield on veld, but this might not have great economic implications. Strong and fairly consistent correlations were observed between summer rainfall (October to March) and air-dry herbage yield, and better yields were obtained in dry years with adequate fertilizalion than in wet years without fertilization. The response of veld to nitrogen-fertilization in terms of crude protein production was much more marked than that of dry matter production.

Keywords: basal covers|sodium|grazing periods|crude proteins|hay|displacements|urea|yields|species lists|veld|nitrates|fertilisation|climax species|grasses|pioneer species|ammonium|sulphates|nitrogen