Research note: The effect of sward height on volatilised nitrogen from a dryland Pennisetum clandestinum Hochst. pasture

Abstract

An experiment, using the micrometeorological mass balance method, was conducted to determine the effect of pasture sward height on volatilized nitrogen (N) losses. An altered sward structure (cut to a height of 30 mm) demonstrated higher volatilized N losses after fertilizer application than a sward retaining approximately 1.00 mm of residual herbage. The mean difference between treatments was estimated at 765 ± 109 g N ha^‐1 (P<0.05) for 33 h after the application of urea at 50 kg N ha^‐1. This implies that residual herbage remaining on a pasture at the time of N fertilizer application may reduce volatilized N from the pasture.