GROWTH AND QUALITY RESPONSES OF TALL FESCUE (Festuca arundinacea Schreb.) TO DIFFERENT IRRIGATION LEVELS AND NITROGEN RATES

A 2-year experiment was conducted to investigate the effects of different irrigation levels and nitrogen rates on visual turfgrass colour and quality and clipping yield of tall fescue (Festuca arundinacea Schreb.) under subhumid climatic conditions. The treatments consisted of five levels of irrigation, 25% (I-1), 50% (I-2), 75% (I-3), 100% (I-4) and 125% (I-5), of the evaporation measured from a Class A pan and two rates of nitrogen, 25 kg N ha(-1) (N-1) and 50 kg N ha(-1)(N-2). The N rates were applied as a monthly rate during growing seasons (May-September). The experimental area was irrigated by a pop-up sprinkler irrigation system. The irrigation was applied at 3-day intervals during May-September for both years. The seasonal crop evapotranspiration (ETc) under the treatments ranged from 315 to 1154 mm in 2007 and from 363 to 1100 mm in 2008. The ETc increased with increasing the both N rate and irrigation level, and the best seasonal turf quality of tall fescue was obtained for the I-4 and I-5 treatments under N-2 rate. This study demonstrated that, when the level of irrigation and nitrogen rate were evaluated together, the N2I4 treatment ensured sufficiently dark turf colour and quality. Based on the results of this study, it is concluded that an acceptable turf quality can be sustained under the N1I1 treatment in May, N1I2 treatment in June, July and August and N1I4 treatment in September (or N2I2 treatment in September) according to water conservation. When rainfall amountis high (132.2 mm) in September, the N1I1 treatment may sustain acceptable turf quality for this month.