Evaporative demands and deficit irrigation on golf courses and other turfgrass areas

While lack of water is a major problem for turfgrass areas worldwide, Scandinavian golf courses have often been over-irrigated resulting in increased mowing costs, disease problems, nutrient and pesticide leaching, and reduced playing quality. By this pro posal, STERF wants to promote scientifically sound, environment-friendly and water-saving irrigation practises. The experimental work will be contracted to Bioforsk, collaborating with scientists from Cranfield University, UK, In WP1, the evapotranspirat ion (ET) of various turfgrass species on greens and fairways will be determined by daily weighing mini-lysimeters installed into the respective areas. The measurements will be conducted during dry-down periods. In half of the lysimeters, ET under non-limi ting water supply (ET0) will be determined by daily replenishment of the ET losses. In the other half of the lysimeters, actual ET (ETa) and leaf elongation rates will be determined under progressive drought. Our hypothesis is that leaf elongation is redu ced, but ETa remains constant until a critical water potential that is species dependent. The principle of deficit irrigation is to maintain turf quality but reduce mowing by always replacing less than the ET0 of well-watered turf. The objective of WP2 is to find the limits for this strategy on an Agrostis stolonifera dominated green and a Festuca rubra dominated fairway. Replacement of 50, 75 and 100% of ET0 will be compared at 2, 4 or 6 days irrigation intervals. Starting 1 July 2009, the trials will be conducted under a fully automated mobile rainout shelter during the seasons 2009-2011. In WP3, the preliminary findings in WP1+2 will be implemented in large scale trials on golf courses, football pitches and in public parks. The trials will be used a ctively for result dissemination. WP4 involves the publication of an irrigation handbook and two scientific papers in international journals. The amount of money applied for is 1.360.000 NOK over four years.