Luxury Water Use by Bermudagrass Turf
- W. R. Kneebone and
- I. L. Pepper2
In an earlier study of the effectiveness of turf-soil filters for tertiary treatment of sewage effluent, we irrigated with effluent at very high application rates, and noticed that water use increased with application rate. This study investigates luxury water use by bermudagrass, and the effect of high application rate on evapotranspiration (ET). The primary objective of this study was to measure the effects of three high irrigation levels (114, 243, and 364 mm 7 days−1) on ET from seeded certified bermudagrass (Cynodon dactylon L. Pers.) turf growing on three sand-soil substrates (19:1, 18:2, and 16:4) mixed with Pima clay loam (fine-silty, mixed, thermic Typic Torrifluvent). The data used were derived from a study of the effectiveness of bermudagrass turf growing in sand-soil mixes irrigated with secondary treated sewage effluent. Percolation lysimeters were irrigated twice each week with effluent. Leachate was collected and measured each week. The difference between applied effluent and recovered leachate measured ET. The lysimeters were arranged in three complete blocks. In each block, the nine treatment combinations of sandsoil mixes and irrigation levels were assigned at random. As irrigation levels increased, ET levels increased. Mean values at the three rates averaged over sand-soil mixes were 31,49, and 53 mm 7 days−1. Evapotranspiration levels were highest on substrates highest in soil, and values averaged over all rates were 36, 44, and 53 mm 7 days−1. Differences due to irrigation levels and to sand-soil mixes were significant at the 0.001 level. Overall rates of irrigation were 254, 540, and 808% of Class A pan evaporation during the 1 year study period. Corresponding ET values were 68, 109, and 119% of Class A pan. Fluctuations in ET paralleled pan evaporation but the ratios of ET to pan were higher during periods of low pan evaporation in winter and spring. Calculations based on solar radiation showed that advective heat from nearby streets and bare ground was a component of the latent heat represented in ET levels measured.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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