Increasing mowing height and nitrogen fertility does not enhance unirrigated centipedegrass summer drought stress

Abstract

Proper N fertilization and higher mowing heights are recommended to enhance rooting for greater turfgrass summer drought stress. To examine the effects of these primary cultural practices on centipedegrass [Eremochloa ophiuroides (Munro) Hack.] drought response in the mid-Southern United States, a study was conducted to evaluate four mowing heights (1, 2, 3 and 4 inches) and N fertilization versus no fertilization. During the study, roots were periodically harvested at upper (0–3 inches) and lower (3–6 inches) soil depths, and roots were analyzed for architecture which included root length (RL) and surface area (SA), and root weight (RW). In July, plant-soil cores were subjected to 36-day drought simulation under greenhouse conditions. All turfgrass exhibited a pattern of decreasing leaf quality as drought progressed with unfertilized treatments maintaining acceptable leaf color (≥5) for 19 days at 5.9 compared to 4.8 for fertilized centipedegrass regardless of mowing height. In the field, root architecture and biomass across all mowing heights, fertilities, and soil depths peaked at 883.9 inches, 35.6 in², and 5.8 grains for RL, SA, and RW, respectively, six weeks prior to drought simulation (WDPS) before declining to 740.5 inches, 29.6 in², and 4.9 grains at the initiation of the drought simulation. The inability of N fertility and mowing height to enhance root growth particularly from spring into summer indicates soil temperatures may be a factor in centipedegrass root growth and thus drought stress avoidance.