Potential of deficit irrigation to increase marginal irrigation response of perennial ryegrass (Lolium perenne L.) on Tasmanian dairy farms

Abstract

In the cool temperate dairy regions of Tasmania, there is heavy reliance on irrigation to maximise pasture performance by ensuring that plants do not suffer water stress. Consequently, irrigation water has often been applied at a greater amount than plant water requirements, resulting in low efficiencies. An irrigation experiment was undertaken in north-western Tasmania between October 2007 and April 2008, examining the effect of deficit irrigation treatments on pasture growth and water-use efficiency. A rainfall deficit (potential evapotranspiration minus rainfall) of 20mm was implemented to schedule irrigation, at which point 20, 16, 12, 8, or 0mm of irrigation water was applied, referred ..