Lotus, White clover and Caucasian clover oversowing, Mesopotamia Station, South Canterbury

Abstract

Results from a legume oversowing and phosphorus topdressing experiment are reported. The depleted tussock grassland site at 700 m altitude with 1000 mm rainfall, soil pH of 5.25 and low available P plus Hieracium weed invasion was typical of much South Island montane grazing land. ‘Grasslands Maku’ lotus (Lotus pedunculatus Cav.) and ‘Grasslands Huia’ white clover (Trilolium repens L.) established rapidly and yields in the second year were similar but lotus gave higher yields subsequently. White clover had lower P% in leaf dry matter and higher scarab populations than lotus. Trijolium umbiguum cv. Prairie establishment was sparse and yields were low at first but after five years it had spread by rhizome growth to form a moderately productive sward. All legume species responded to increasing rates of P at establishment and to greater frequency of maintenance superphosphate but the most efficient superphosphate regime was for low to moderate rates (123 to 300 kg/ha) at sowing reinforced by annual topdressings at 125 kg/ha. Legume oversowing with fertilizer substantially reduced Hieracium pillosella cover.