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n recent times there has been a lot of fuss within the turf production industry regarding the awarding of grasses a tick of approval regarding their water usage rate. One particular grass was granted such an approval for the east coast of Australia, but not the whole of Australia. Why not? Because the turf community in Western Australia, headed by the researchers at the University of WA, were not happy with the data presented for the request of such approval and rejected it being given for the state. So how do you sensibly test grasses so that you can quickly tell if they are high water users or low water users? This is not easy because the quickest way is to use pot tests of restricted root volume under rain out protection, using weighing replacement of water lost. The key here is restricted root volume, because the expression of their genetic root volume by grasses in the field is the only real meaningful way of characterising one grass against another. Restricted root volume means restricted data on water use. In this context let us look further into the crystal ball and see where we get to. How much water does your turf need to perform and what makes for efficient use of water by various turf grass varieties? Over the
last century there have been a huge number of studies looking at these basic problems and how to understand them. The concepts of LAI (leaf area index) and ET (evapotranspiration) measurements and all the derived data from these using Penman-Monteith equations, the relationships of these to a standard Class A Pan evaporation surface, detailed weather stations etc… have all featured along the way. Soil/moisture tension meters to tell you what the soil was holding were early attempts to measure available soil moisture in situ. These used ceramic cups, while Australian inventor Ken Cumming used gypsum blocks more successfully. Are we any nearer to getting solutions? In the 1960s to 1970s there were many sprinkler set ups created to provide moisture gradients for investigating water use by various turf grass species and varieties. The man whose name stands out in almost every meaningful study of this kind is Dr Garald Horst. Never mind how many other names were on the papers produced, he was the brains behind the design work. It was also at this time that we saw an explosion in the sophistication of irrigation design both in the area of sprinkler heads and the control valves, but also in the computer hardware and programmes for managing delivery.
One of the leading lights in this area was Ed Hunter, initially in his days at Toro and then later with his own company, Hunter Industries. Along with these developments were the rising tides of design reform in delivery pumps as electronics made submersible pumps a reality. In 1985 a seriously good publication Turfgrass Water Conservation was put out by the University of California Riverside (UCR) edited by Dr Vic Gibeault and the late Steve Cockerham. This eminently practical book was later issued in 2011 in a revised edition with Cockerham and Bernd Leinauer as editors. Another excellent reference, Evapotranspiration and Irrigation Scheduling, was published in 1996 in the Proceedings of the International Conference of the American Society of Agricultural Engineers. In Australia, CSIRO and various universities have looked at any number of the limiting factors for crop production and soil water capture. Among the leading lights in the area was Dr E. Linacre who was at both Sydney and Macquarie University and whom I was privileged to have on my scientific advisory committee at the Australian Turf Research Institute. The most recent research in Australia for turf has been done at the University of WA funded by HIA industry funds and the Federal Government.
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