Yield benefits of pasture mixtures with species drilled in the same and alternate rows

Abstract

This study investigated the effect of sowing species in alternate drill rows on dry matter (DM) yield of pasture mixtures. Seven mixtures of ‘Base’ perennial ryegrass, ‘Tonic’ plantain and ‘Apex’ white clover (three pure, three binary and one ternary) were drilled into plots in March 2015 at Lincoln University. Binary and ternary mixtures were also sown with species in alternate drill rows. Ryegrass-white clover and plantain-white clover mixtures yielded more than the average monoculture yields of their constituent species (over-yielding). This diversity effect averaged 7.01 t DM/ha in Year 1 (2015/2016) and 3.45 t DM/ha in Year 2 (2016/2017) of sown yield (total minus weeds) when species were drilled together. Diversity effects were due to synergistic interactions and white clover interacted more strongly with plantain than ryegrass. There was no additional yield benefit from increasing the number of species from two to three in the mixture, and from sowing species in alternate rows.