Utilizing Trifolium Species in Managed Turfgrass Polycultures: Establishment and Maintenance Issues.

Including and managing for legume biodiversity within turfgrass offers a means of maintaining adequate soil nitrogen. However, little is known about establishing and maintaining turf-legume polycultures. Our research reveals practical information concerning establishment and management of Trifolium spp. in maintained turf.

Legumes, such as Trifolium spp., host soil-born bacteria within their roots which are capable of biologically fixing atmospheric nitrogen. However, information concerning pre-plant inoculation with clover specific bacterium is limited. Our analysis failed to detect root nodulation differences due to inoculation by N-rate interaction or by inoculation main effect. N-rate had a limited effect upon acute clover phenology, including many important leaf characteristics.

Three studies were initiated on October 22, 2010 to evaluate white-clover (T. repens) establishment methodology, seeding rate, and timing within bermudagrass. Scalping, verticutting, or small tine aerification prior to seeding (1.5 g m^-2) resulted in greater clover density (530 trifoliate leaves m^-2) than did non-treatment (3.8 cm un-mown turf; 375 trifoliate leaves m^-2). Seeding rate was highly correlated with plant densities. Across rates, nearly 10% of all seed resulted in successful plant establishment. Fall to early winter establishment is likely necessary for adequate spring plant density. Due to reduced germination and plant survival, November through February seeding dates resulted in limited clover establishment.

Greenhouse and field experiments evaluated cool-season legume (T. repens, T. dubium, T. arvense, T. incarnatum, T. nigrescens, and Medicago arabica) response to common turf herbicides. Efficacy was evaluated weekly. In general, bentazon (<20% injury) and imazethapyr (<35% injury) were least injurious to all species while dicamba, clopyralid, triclopyr, and atrazine effectively controlled all species. All clovers were partially tolerant to 2,4-DB (<70% injury). Other notable results include rabbitfoot-clover tolerance to trifloxysulfuron and white clover tolerance to MCPA. These results indicate varying tolerances between legume species and common turf herbicides.