Summer production of alternative species in comparison to perennial ryegrass and white clover for high input pasture systems

The increase in irrigable land in the Midlands region of Tasmania presents an opportunity to increase animal production, whether it is lamb, dairy or beef. However, challenges including low rainfall (<650 mm annual average rainfall, high amounts of irrigation are required to maintain soil moisture), high summer temperatures (days >27°C) and duplex winter wet soils in this region put into question the suitability of the traditional intensive pasture base of perennial ryegrass Lolium perenne and white clover Trifolium repens. This study evaluated the performance of alternative grass and legume species under high input management for diversifying the feedbase in this region. The experiment was sown with 29 pasture treatments consisting of mixed swards and monocultures of 5 grass species (perennial ryegrass, tall fescue Festuca arundinacea, coloured brome Bromus coloratus, cocksfoot Dactylis glomerata and phalaris Phalaris hybrid) and 4 legume species (white clover, red clover Trifolium pratense, strawberry clover Trifolium fragiferum and Caucasian clover Trifolium ambiguum). The experiment was fully irrigated and nitrogen was applied at 40 kg N/ ha following each harvest event. Dry matter (DM) yield was assessed at six defoliation events between November 2014 and April 2015. Perennial ryegrass and coloured brome were the best performed grasses, with coloured brome only significantly (P<0.05) lower than perennial ryegrass on one of the six harvest dates. The addition of the 4 clover cultivars to each of the 5 grass swards made no significant difference to yield except where white clover was in combination with phalaris. This study highlights the potential of coloured brome as an alternative to perennial ryegrass in high input systems although its tolerance of waterlogging, typical in the Midlands region requires further evaluation.