Yield of Italian ryegrass mixed with red clover and balansa clover

Abstract

A mixture experiment was conducted at Lincoln University to investigate if mixtures of Italian ryegrass, red clover and balansa clover gave more high quality forage and suppressed weeds better than Italian ryegrass monocultures. Thirteen seed mixtures with varied species proportions were sown at 20 and 30 kg/ ha in March 2011. The minimum amount of Italian ryegrass was 50% of the total sowing rate. Plots were harvested six times over 12 months and were neither irrigated nor fertilised. Inclusion of red clover increased yield by 41% compared with the Italian ryegrass monocultures (13.79 vs. 9.75 t DM/ha), and provided effective weed suppression (<5% of total annual yield) and high quality forage (17.5% crude protein, 11.3 MJ/ kg DM metabolisable energy). No benefits were gained from mixing balansa clover with Italian ryegrass. The optimum seed mixture was 12 kg/ha of Italian ryegrass, 8 kg/ha of red clover and no balansa clover. Keywords: dryland, greenfeed mixtures, simplex design