Effects of nitrogen on oversown tussock grassland

Abstract

This trial investigated the effect of fertiliser nitrogen (N) on the productivity of tussock grassland oversown with a mixture of red and white clovers (Trifolium pratense L. and T. repens L. respectively) or ‘Grasslands Maku’ lotus (Lotus pedunculatus Cav.) and with or without a mixture of grasses. Seven weeks after 40 kg N/ha had first been applied, N had increased total dry matter (DM) yields by 64% (22 kg DM kg-1 applied N ha-1) and doubled the contribution to total yields of the sown grasses from 12 to 25%. During the 3 years of the experiment the efficiency of fertiliser N was estimated to be ≃ 36 kg DM kg-1 applied N ha-1. Nitrogen had no effect on legume productivity. Oversowing grasses had no effect on DM production, a result which brings into doubt the value of oversowing grasses into tussock grassland where there is already an appreciable exotic grass component. © 1985 Taylor and Francis Group, LLC.