Strategies to improve sheep liveweight gains and dry matter production of dryland tall fescue/clover pastures in Canterbury

Abstract

This study examined ways to improve sheep liveweight gains and dry matter production on dryland Canterbury farms using tall fescue/clover pastures. There were four pasture mixes sown in 2008 at Lincoln University. Each combination included one tall fescue cultivar (‘Advance’ (continental, summer active type) or ‘Flecha’ (Mediterranean, winter active type)) with either white clover (‘Nomad’) or subterranean clover (‘Denmark’ and ‘Campeda’), and was repeated at low (8 mg P/L) and high (18 mg P/L) soil fertility. Sheep liveweight gains and pasture yields were measured during the seventh year (2014). From 17 March to 27 May, the hoggets on the tall fescue/subterranean clover pastures gained 37 g/head/day compared with 14 g/head/day on tall fescue/white clover pastures at a similar stocking rate (31.3 sheep/ha). Clover content in the subterranean clover pastures was 8.5% compared with 5.6% in the white clover pastures. ‘Denmark’ was more abundant than ‘Campeda’ in the subterranean clover pastures after 6 years. ‘Flecha’ tall fescue swards produced more DM yield, but the yield had more weeds (49%) and less tall fescue (30%) than ‘Advance’ swards (34% and 46%). Subterranean clover pastures at high soil fertility provided a greater total herbage yield (6180 kg DM/ha) than white clover/high fertility pastures (6072 kg DM/ha), which contained more weeds than subterranean clover swards. Soil in the ‘Advance’/high fertility pastures contained more anaerobically mineralisable N (116 kg N/ha) than the ‘Flecha’/high fertility pastures (100 kg N/ha), but both treatments produced similar clover yields. Total N content in the top 7.5 cm of soil in subterranean clover pastures (0.226%) was higher than in the white clover pastures (0.218%), suggesting that the subterranean clover pastures fixed more N. The final recommendation obtained from the results of this study was that ‘Advance’ tall fescue should be sown with ‘Denmark’ subterranean clover in high fertile soils as a strategy to improve sheep liveweight gains and DM production of dryland tall fescue swards in Canterbury.