WHITE CLOVER RESPONSE TO A WATER-APPLICATION GRADIENT

Periods of drought, common during the summer and fall in the southeast ern USA, can be detrimental to growth of the shallow-rooted, temperate forage legume, white clover (Trifolium repens L.), Our objective was to determine the growth response (lateral spread, morphology) of white clover to a water-application gradient during the summer and fall on a Marietta fine sandy Loam (fine-loamy, siliceous, thermic Fluvaquenti c Eutrochrept). From May to October, a line-source irrigation system p roduced regimes of high, medium, low, and zero water-application acros s parallel 1.0-m rows of three cultivars and three germplasms transpla nted (10 plants row(-1)) into a common bermudagrass (Cynodon dactylon (L.) Pers, var. dactylon:) sod the previous fall. Plots were continuou sly-stocked (5-cm stubble) with cattle (Bos taurus L.). Each month, di fferences in lateral plant spread among entries were similar regardles s of water-application regime. Within each regime, spread declined sha rply after June and remained near a minimum (<0.20 m(2) row(-1)) from August until October, Yield and morphology differences among entries i n July were similar in each of the water-application regimes as well. By October, however, there were differences in herbage yield, stolen l ength, and number of stolen apices among entries at the high water-app lication regime, but not at the medium, low, and zero regimes. The res ults suggest that either there is no difference in drought tolerance a mong these cultivars and germplasms, or that white clover drought tole rance does not impact growth in the presence of stresses such as grazi ng and associated grasses.