Evaluation of Mowing Height and Fertilizer Application Rate on Quality and Weed Abundance of Five Home Lawn Grasses

Abstract

Evaluation of turfgrass performance at low nitrogen fertility levels is important because many home lawns are fertilized below common recommendations. The objective of this study was to evaluate visible quality and weed susceptibility of common and alternative cool season grasses under multiple management regimes in Wisconsin. A split-split plot completely randomized block design was used to evaluate ‘Kingfisher' Kentucky bluegrass (Kentucky bluegrass), ‘Kenblue' Kentucky bluegrass, ‘Victory II' chewings fescue, ‘Grande II' tall fescue, and ‘Jiffe II' perennial ryegrass. Each species was mowed at 3.5, 6.0, or 8.5 cm, and fertilized with 0, 98, or 196 kg ha−1yr−1of nitrogen. Visible quality and weed cover were evaluated four times annually for 3 yr. Tall fescue had the greatest turf quality across all treatments. Kingfisher Kentucky bluegrass, an improved variety, responded most dramatically to nitrogen fertilization, with quality rating improved from 5.1 to 7.1 when annual nitrogen applications totaled 196 kg ha−1compared to the nonfertilized control. Kenblue Kentucky bluegrass, a common variety, had the greatest weed cover at all mowing heights and fertilizer rates. Assessment of common dandelion flowers by digital image analysis revealed that improved and common Kentucky bluegrass had greater common dandelion cover than fine or tall fescue when herbicides were withheld for 2.5 yr. Background soil fertility was found to have a significant impact on visible quality and weed cover. In an area with eroded, low-fertility soil, improved Kentucky bluegrass required 196 kg N ha−1yr−1to maintain high quality and limit weed invasion. These results suggest that tall fescue is best suited to low and high input conditions, while improved varieties of Kentucky bluegrass performed acceptably only under high inputs.