The influence of subterranean clover pastures on soil fertility. II. The effects of certain management systems

Abstract

Three systems of pasture management were examined to assess the role of clover herbage in the build-up of soil fertility. In one system herbage was returned to the soil via the grazing animal as dung and urine; in another it was returned as dried plant material; and in the third it was discarded.

The rate of accumulation of soil nitrogen (72 lb/acre/annum) was not significantly affected by treatment. Moreover, four consecutive cereal crops which followed the clover ley showed no significant differential effects of the management systems on total yield, grain yield, or nitrogen uptake.

Nitrogen loss from the excreta and from returned herbage, and reduced nitrogen fixation due to the return of nitrogen in the excreta and herbage, were considered to be the factors mainly responsible for the absence of differential treatment effects.

The indispensability of the grazing animal for the maintenance or build-up of soil fertility is questioned.