Irrigation requirements, drought tolerance, and stability of warm‐season legumes intermixed in turfgrass

Abstract Integrating legumes into turfgrass systems can reduce nitrogen fertilizer needs in urban landscapes through biological nitrogen fixation while enhancing plant biodiversity in urban lawns. However, the persistence and water requirements of these associations have not been evaluated in warm‐season lawns. A field study was conducted from June 2021 to July 2023 at the University of Florida's West Florida Research and Education Center (Jay, FL) using a linear gradient irrigation system. In June 2021, three perennial peanut (PP) cultivars—Golden Glory ( Arachis pintoi Krapov. & W.C. Greg), Ecoturf ( Arachis glabrata ), and Cowboy ( A. glabrata )—along with the US native Mimosa strigillosa , were interplanted in centipedegrass ( Eremochloa ophiuroides Munro), St. Augustinegrass [ Stenotaphrum secundatum (Walt.) Kuntze], and bahiagrass ( Paspalum notatum Flugge). The experiment was arranged as a split‐strip‐block design with four replicates. The objectives were to evaluate the percent cover of the legumes when growing with three different turfgrass species under an irrigation gradient and to estimate the stress coefficients (Sc) and soil volumetric water content thresholds to maintain acceptable legume quality. Overall, most legumes increased in cover since trial initiation when examined under mowing heights of 5.0–7.6 cm. The average Sc for Cowboy, Ecoturf, mimosa, and Golden Glory were 0.29, 0.32, 0.37, and 0.73, respectively. The rhizomatous peanuts and mimosa exhibited greater drought tolerance and lower irrigation requirements than turfgrass monocultures, highlighting their potential for water conservation via reduced irrigation inputs. Results show that rhizomatous PPs like Ecoturf and Cowboy could be interplanted into turfgrasses to enhance lawn sustainability.