Water availability is becoming limited across many areas of the United States. In recent years, deficit irrigation, or application of water at levels less than maximum evapotranspiration (ET) demand, has been practiced as a strategy to minimize water, resulting in overall water savings. An irrigation deficit can be achieved by returning less water than would occur through actual ET. In some cases, this involves extending the time between irrigations and, in other cases, applying water amounts less than actual ET on a more frequent schedule. Deficit irrigation has been successfully used on some turfgrasses for water conservation without significant loss of turf quality (Brown et al., 2004; DaCosta and Huang, 2005; Feldhake et al., 1984; Fry and Butler, 1989).
Growth and physiological changes of turfgrasses in response to deficit irrigation are not well understood. Growth rate and tiller density may be impacted as may carbon metabolism. Reductions in growth during water deficits are related to a negative whole-plant carbon balance that results from photosynthetic capacity declines during drought. Maintaining a balance between photosynthesis and respiration is particularly important for plants to survive a long-term water deficit, because each may be differentially affected (Pande and Singh, 1981).
Water use efficiency (WUE), expressed as the amount of water lost through ET relative to the amount of carbon fixed, may also be affected by deficit irrigation. Generally, higher water use rates in turfgrasses are associated with increased soil water availability (Beard, 1973). Turfgrass subjected to deficit irrigation or limiting soil moisture may use less water when compared with well-watered turfgrass (Qian and Engelke, 1999). Overall, the extent of allowable deficit irrigation may vary among species and cultivars with warm-season grasses typically being better able to withstand greater levels of deficit irrigation when compared with cool-season grasses (Carrow, 1995; Qian and Engelke, 1999).
In an earlier publication that presented turf quality responses to deficit irrigation in the same study area described here, we reported that tall fescue quality in Kansas was acceptable between June and September when irrigated at 60% and 80% of actual ET in 2001 and 2002 (Fu et al., 2004). However, if the turfgrass manager could tolerate 1 week of unacceptable quality, then a MDIL of 40% and 60% in 2001 and 2002, respectively, would have sufficed. Zoysiagrass quality was acceptable only when irrigated at 80% ET. Using the lower MDIL assumptions for tall fescue and 80% ET irrigation for zoysiagrass, tall fescue required 28% less water than zoysiagrass in 2001 and the same amount of water as zoysiagrass in 2002.
Our objective was to determine growth and physiological impacts of the previously reported MDIL on tall fescue and zoysiagrass, and also evaluate responses across all deficit irrigation levels.
Biran, I., Bravdo, B., Bushkin-Harav, I. & Rawitz, E. 1981 Water consumption and growth rate of 11 turfgrasses as affected by mowing height, irrigation frequency, and soil moisture Agron. J. 73 85 90
Brown, C.A., Devitt, D.A. & Morris, R.L. 2004 Water use and physiological response of tall fescue turf to water deficit irrigation in an arid environment HortScience 39 388 393
DaCosta, M. & Huang, B.R. 2005 Minimum water requirements for creeping, colonial, and velvet bentgrass under fairway conditions Crop Sci. 46 81 89
DaCosta, M., Wang, Z.L. & Huang, B.R. 2004 Physiological adaptation of Kentucky bluegrass to localized soil drying Crop Sci. 44 1307 1314
Ebdon, J.S. & Kopp, K.L. 2004 Relationship between water use efficiency, carbon isotope discrimination, and turf performance in genotypes of Kentucky bluegrass during drought Crop Sci. 44 1754 1762
Feldhake, C.M., Danielson, R.E. & Butler, J.D. 1984 Turfgrass evapotranspiration. II. Responses to deficit irrigation Agron. J. 76 85 89
Huang, B. & Fu, J. 2000 Photosynthesis, respiration, and carbon allocation of two cool-season perennial grasses in response to surface soil drying Plant Soil 227 17 26
Huang, B. & Fu, J. 2001 Growth and physiological responses of tall fescue to surface soil drying Intl. Turfgrass Soc. Res. J. 9 291 296
Huang, B. & Gao, H. 2000 Growth and carbohydrate metabolism of creeping bentgrass cultivars in response to increasing temperature Crop Sci. 40 1115 1120
Pande, H. & Singh, J.S. 1981 Comparative biomass and water status of four range grasses grown under two soil water conditions J. Range Mgt. 34 280 284
Qian, Y.L., Fry, J.D. & Upham, W.S. 1996a Rooting and drought avoidance of warm-season grasses and tall fescue in Kansas Crop Sci. 31 1331 1334
Qian, Y.L., Fry, J.D., Wiest, S.C. & Upham, W.S. 1996b Estimating turfgrass evapotranspiration using atmometers and the Penman-Monteith model Crop Sci. 36 699 704
Saradadevik, R.A. 1994 Inhibition of photosynthesis by osmotic-stress in pea (Pisum-sativum) mesophyll protoplasts in intensified by chilling or photoinhibitory light-intriguing responses of respiration Plant Cell Environ. 17 739 746
Schmidt, R.E. & Blaser, R.E. 1967 Effect of temperature, light, and nitrogen on growth and metabolism of ‘Cohansey’ bentgrass (Agrostis palustris) Crop Sci. 7 447 451
Starman, T. & Lombardini, L. 2006 Growth, gas exchange, and chlorophyll fluorescence of four ornamental herbaceous perennials during water deficit conditions J. Amer. Soc. Hort. Sci. 131 469 475