Herbage yield and botanical composition of Italian ryegrass forage crops associated with different types of nitrogen supply

Abstract

Italian ryegrass monoculture and mixtures with red clover (sowing ratios 75:25%, 50:50% and 25:75%) were established in the spring of 2008 at the Institute for Animal Husbandry, Belgrade, with the aim to analyse the possibilities of managing the N supply. There were four N rates for Italian ryegrass monoculture: 0, 100, 150 and 200 kg ha(-1), whilst no N fertilizer was applied to the mixture plots. The trial was carried out during 2008-2010 and the highest total DM yield was obtained with 200 kg N ha(-1), similar to that of the ryegrass-clover mixtures. Ryegrass contributed less to the total yield in the mixtures, because it had lower ratios in the structure of swards than those used at sowing. An Italian ryegrass-red clover sward may have advantages over a pure Italian ryegrass sward fertilized by high rates of N, providing high yield with a more sustainable land-use system.