Changes in forage yield and botanical composition in a species diversity by harvest height by frequency experiment over 3 years in Hawke’s Bay

Abstract

There has been considerable interest in regenerative agriculture and the potential impact of diverse forage mixtures and grazing to higher residuals on pasture production and soil quality. This study evaluated the species mixtures at three defoliation heights and two defoliation frequencies. The experiment was carried out over 3 years at a summer-dry site in Hawke’s Bay. The treatments were: mixtures of six cultivars of four species (ryegrass/clover) and 18 cultivars of 16 species (diverse), defoliation heights of 5, 10 and 15 cm to replicate normal, lax and very lax grazing, and defoliation frequencies of 4 and 8 weeks, over the 3 years. Total dry matter production was 23,910 kg/ha for the diverse mixture compared with 19,060 kg/ha for ryegrass/clover and decreased from 29,410 kg/ha for the 5 cm defoliation height to 21,200 kg/ha for 10 cm and 13,840 kg/ha for 15 cm, with no effect of defoliation frequency. As defoliation height increased, so did the amount of dead matter, and thus feed quality would have declined. The greater dry matter production in the diverse mixture was likely to be at least partially due to the presence of chicory and plantain.