COLUMBUS, Ohio – Researchers at The Ohio State University are studying the introduction of Microclover into turfgrass to test the feasibility of developing a more environmentally friendly, sustainable turfgrass ecosystem. They gave a brief overview of the study at the university’s turfgrass field day this past August.

Speakers at the OSU Field Day stressed that sustainability and reduced cultural inputs in turfgrass management are becoming increasingly important in the eco-friendly/green movement in society today. White clover (Trifolium repens) is considered an undesirable species in turfgrass swards. There are potential benefits to the inclusion of legumes in turfgrass mixtures to increase sustainability by reducing cultural inputs.

Microclover (Trifolium repens L. microclover) is a leguminous species. Legumes can fix nitrogen from the air. This N-fixation takes place in root nodules that are formed by symbiotic Rhizobium bacteria. The continuous process of parts of the roots dying and degenerating means that the accumulated nitrogen is made available tothe surrounding grass plants, says literature from DLF-TRIFOLIUM. 

Microclover, a registered product from DLF-TRIFOLIUM, is a clover species touted to be more diminutive in growth habit and reduced flowering resulting in better compatibility in a turfgrass sward compared to white clover. 

The OSU turf team is investigating the benefits of Microclover in mixtures in Kentucky bluegrass and tall fescue (5 percent Microclover by weight) to determine the ecological dynamics of a Microclover/turfgrass mixture, in reducing cultural inputs (fertilizer, pesticides and water) and enhancing sustainability. The study is evaluating turf color, turf quality, sward composition, soil and sward nitrogen content, weed populations and drought tolerance for the potential benefits and use of Microclover in turfgrass management systems.

The drought tolerance study is being conducted at The Ohio State University Research and Education Facility here. The treatments consist of tall fescue alone, tall fescue in combination with microclover, tall fescue and fertilizer, tall fescue with fertilizer and microclover, Kentucky bluegrass and fertilizer and Kentucky bluegrass with microclover and fertilizer. The plots were seeded on Sept. 14, 2011. Tall fescue was seeded at 8 lbs./1,000 square feet and the Kentucky bluegrass was seeded at 2 lbs. /1,000 square feet. Microclover was seeded at the recommended rate of 5 percent by weight of the grass species.

Fertility (starter fertilizer) was included in all treatments at seeding and again in the spring to promote establishment. The fertility treatment regime consists of four applications per year. The grass/fertilizer treatments will receive a season total of 3 lbs. of N/1,000 sq. ft., and the grass/microclover /fertilizer treatments will receive a season total of 2 lbs. N/1,000 sq. ft.

A rain-out shelter was constructed to cover the study during the dry-down/drought stress periods to reduce drought stress. The shelter consists of two 18 ft.-18 ft. garage doors mounted horizontally on rails attached to a treated lumber framework. The doors move over the study plots during rain events and rest between them otherwise.

Plots are monitored for quality, turfgrass color, weed invasion, disease incidence, clipping yield, percent microclover, visible drought stress, percent soil moisture, canopy temperature and microclover flowering. Soil and tissue samples are being analyzed twice a year for total nitrogen.Irrigation is provided as needed except during the dry-down, drought-stress periods.