Effect of fertilizer nitrogen on a dense sward of kikuyu, paspalum and carpet grass. 3. Nitrogen source

Abstract

In a 1-year experiment on red brown clay loam of pH 5.8 (1: 2.5 H2O) receiving a split application of NH4NO3, (NH4)2SO4, NaNO3 or urea at 50, 100, 200 or 400 Ib/acre N per year, dry-matter yields and N-yield responses to N were linear for all sources. At some harvests, significant interactions occurred between source and rate for dry-matter yield, N concentration and N yield. Generally, at 50 and 100 Ib/acre N there were no differences between sources, but at 400 lb/acre N, NH4NO3 produced 3 320 lb more dry matter per acre than urea. N recovery from NH4NO3 was 92% as against 58% for urea.