Development of a high country winter-feed option using irrigated nitrogen-fertilised tall fescue

Abstract

A 2 ha 6-year trial on pure stands of irrigated Grasslands Roa tall fescue compared the effect of high (600-300 kg N/ba/yr as urea) and moderate (300-150) nitrogen rates split over either 2- or 4- weekly application, on hay production, some summer grazing and autumn regrowth prior to winter and fed to pregnant ewes on the same plots. Annual yields averaged 13.8 t DM/ba with a 24% advantage to high N. Pregnant ewes break fed a mixed allowance of hay and grass regrowth lost c. 2.4% body weight over a g-week winter period. There was thinning of the stands under high N and long summer regrowth period. It was considered better to forego some of the winter feed potential for some summer grazing, or a further hay cut, to maintain stand density.