Nitrogen and Cutting Height Influence Root Development during Warm-Season Turfgrass Sod Establishment
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Effective water conservation in the landscape requires identification of cultural management practices that maximize the genetic rooting potential of establishing turfgrass sod. Nitrogen is critical for successful turfgrass establishment; however, there has recently been debate over whether to restrict N fertilization during summer periods in parts of Florida and the United States. This study was undertaken to examine within four warm-season turfgrass species, the relative influences of cutting height and N fertility on the (i) rate of root extension and (ii) root biomass produced over a 10-wk period. 'Tifway 419' bermudagrass (Cynodon dactylon (L.) Pers. C. transvaalensis Burtt Davy), 'Empire' zoysiagrass (Zoysia japonica Steud.), 'Argentine' bahiagrass (Paspalum notatum Flugge), and 'Floratam' St. Augustinegrass (Stenotaphrum secundatum Walt. Kuntze) were established from 10-cm diam. by 5-cm deep plugs of turfgrass sod into 90-cm tall, clear acrylic tubes. Experimental treatments were arranged in a complete factorial that was repeated over two growing seasons. Rates of root extension were calculated from weekly measures of the deepest visible root in each column. Root extension rates ranged from ~1.0 to 1.8 cm d -1 during the studies, with bahiagrass exhibiting the most rapid root extension of the four species. The results demonstrated that increasing N fertility during establishment increased rates of root extension into deep soil, particularly in bermudagrass. Height of cut had no effect on rate of root extension for most species, but higher cutting height did promote more rapid root extension in bermudagrass. Although not significantly accelerating vertical root extension in most species, maintaining sod at the higher cutting heights resulted in significantly greater root proliferation within both upper and lower soil depths for all species. The results emphasize the importance of proper N fertility and cutting heights for optimizing root development of different turfgrass species during sod establishment 2011 by the American Society of Agronomy.