Management strategies to improve water-use efficiency of barley in Tasmania

Tasmania’s mild climate, long growing season and access to irrigation are amenable to the production of high-yielding cereal crops. For malting barley, the extended sowing window (winter to spring) and price premium makes it a flexible and potentially more profitable alternative to other grains in crop rotations. Barley is one of the few grain crops that can be sown late where waterlogging has prevented timely sowing of other crops or there has been a crop failure. However the shorter growing season and additional costs associated with irrigation and the lower yield potential of barley may reduce grower profits. Consequently there has been a trend towards earlier sowing to take advantage of winter rainfall, which however comes at the risk of greater frost damage at anthesis. Strategic nitrogen and irrigation management are also critical, so as to meet grain quality requirements for malting. Crop water-use efficiency (WUE) is an integrative measure of the impact these management strategies have on production, but there are few reports for WUE of barley in this environment. Grain yield was collated from field trials of barley conducted in Tasmania from 2008 to 2011 and WUE determined from crop simulation modelling. There was a good relationship between simulated and observed grain yield (r² = 0.83) and WUE ranged from 7 to 24 kg/ha.mm. The modelled impact irrigation management and time of sowing on predicted grain yield, WUE and quality are discussed.