Irrigated lucerne with perennial grasses and Tama ryegrass for prime lamb production

Abstract

To improve the system of irrigated lucerne-Tama ryegrass for prime lamb production as outlined by Vartha & Fraser (1978), the period of hay feeding in winter needed to be reduced, as the required amount of hay could not be obtained within the system. So, pastures of Matua prairie grass and Maru phalaris (both with lucerne), and of Nui ryegrass with white clover, were added to the existing system. Comparison between this extended system and lucerneTama was made over 3 years. For the lucerne-Tama system, hay produced was only 53% of that required for supplementary feeding in winter over 100 days. For the extended system, the perennial grasses enabled later grazing in autumn and earlier grazing in late winter with the result that winter feeding was required only over 62 days, and hay made in the system exceeded that required by 40%. Whereas the lucerne-Tama system, stocked at 25 ewesha and offered 12 t DM/ha per year, produced 470 kg meat/ha (with 88% of lambs exceeding 25 kg liveweight) the extended system, stocked at 22 ewes/ha and offered 12.15 t DM/ha per year, produced 390 kg meat/ha (with 91 % of lambs exceeding 25 kg liveweight). A final stocking rate/production result was not reached for the extended system, because insect attack of lucerne ended the experiment. Maru phalaris was successfully maintained with lucerne, but Matua prairie grass dominated lucerne in the first winter from sowing and subsequently became a mixture with unsown white clover. Keywords