CREEPING BENTGRASS CULTIVAR WATER-USE AND ROOTING RESPONSES

Low evapotranspiration (ET) rates and deep extensive root systems are desirable drought avoidance characteristics. In this study, 10 creeping bentgrass (Agrostis palustris Hudson) cultivars were evaluated for ET and rooting responses. Evapotranspiration measurements were made in the field during 1987 and 1988 using minilysimeters filled with fritted clay. Crop coefficients (Kc) were determined for each cultivar using a Nebraska modified Penman equation for potential ET. Root distribution experiments were conducted in a controlled environment using a specially designed hydroponic system. Cultivar ET rate differences were repeatable over the 2-yr field study. 'Seaside' and 'SR-1020' ranked high in ET and had Kc values consistently > 1, while 'Pennlinks' and 'National' ranked low, with Kc values consistently < 1. Cultivars differed for total root production and root distribution. 'Cobra', 'Pencross', Pennlinks, 'Providence', and SR-1020 produced roots to depths of 600 to 750 nm. 'Emerald', 'Prominent', and 'Penneagle' did not produce roots beyond 450 mm. Evapotranspiration rate and root distribution variability among creeping bentgrass cultivars could serve as selection criteria in a turfgrass breeding program interested in improving drought resistance.