In Pursuit of the “Self Feeding Lawn”: Exploring the Feasibility of Grass-Legume Species Mixtures for Lawns.

Nitrogen (N), is the nutrient required most in turfgrass systems and is the most common nutrient deficiency. As a result, fertilizers are applied to provide supplemental N. The practice of fertilizing turfgrass systems has received public criticism due to off target movement of the fertilizer, ultimately disrupting ecological systems and compromising water quality. This event has led to alternative strategies to supplement lawns’ nutritional needs while also protecting the environment and water quality. A legume is a plant that is able to access N from the atmosphere and turn it into a usable form during a process called N-fixation. During the N-fixation process, N is added to the soil over time becoming available to the grass plant. To examine the feasibility and management of a grass-legume system, a field study was initiated to evaluate and compare a traditional, cool-season-lawn mixture, and the mixture combined with Trifolium repens var.‘Microclover’ under two N-fertilizer regimes. The turf was fertilized with 0 or 97.74 kg N/Ha/Yr and applications split into five increments across the growing season. Data recorded for the study included seasonal growth (dry matter yield: DMY), visual appearance, clover populations, and canopy greenness as reflectance was measured. Total DMY for the first year for traditional cool-season and combined ‘Microclover’ lawn mixtures receiving 0 kg N/Ha/Yr were 2776.87 kg/Ha/Yr and 5303.02 kg/Ha/Yr respectively. Total DMY for the traditional cool-season and combined ‘Microclover’ lawn mixtures receiving 97.74 kg N/Ha/Yr were 5118.71 and 7140.42 kg/Ha/Yr. Total DMY for the second season through July for traditional cool-season and combined ‘Microclover’ lawn mixtures receiving 0 kg N/Ha/Yr were 764.78 and 2265.12 kg/Ha/Yr respectively, and the traditional cool-season and combined ‘Microclover’ lawn mixtures receiving 97.74 kg N/Ha/Yr were 4987.57 and 5389.81 kg/Ha/Yr. Future research needs include how annual N rates and N sources affect clover populations.