ODA Low-Input

Refining best management practices for nitrogen applications to cool-season turfgrass lawns across Ohio

T. VanLandingham, D. Petrella, E. Nangle, D. Gardner.

Introduction:

Turfgrass lawns need nitrogen fertilizer to be healthy. Healthy turfgrass areas provide erosion control, temperature control, increase air quality, purify water, sequester carbon, and increase quality of life for humans. There are currently NO guidelines for annual rates of nitrogen fertilizer applications in the state of Ohio. A survey from the Ohio Lawn Care Association found that respondents applied between 1.5 and 7 lbs/1000sqft of nitrogen to turfgrass lawns over the course of a growing season. Over-fertilization contributes to more surface runoff and leaching of nitrogen into water sources, affecting water quality and negatively impacting the environment. This issue is a concern for the state of Ohio and so industry needs guidelines to help them provide high quality surfaces while having minimal impact on the environment.

The objectives of this trial were to develop refined best management practices for nitrogen fertilizer applications for home lawns and high-cut turfgrasses across Ohio and examine to what extent different turfgrass species and new turfgrass cultivars affect nitrogen needs in order to reduce nitrogen fertilizer use.

Materials and Methods:

Four locations were chosen across the state of Ohio to encompass as much climate variability as possible: Columbus, Cincinnati, Wooster, Findlay. The seeding dates and cultivars can be found below (Table 1). All sites were set up as randomized complete block (RCB) split-plot design w/ repeated measures accounting for nitrogen applications. Annual Nitrogen (N) rates were 0.0, 0.5, 1, 2, 4lbs N/M/yr and treatments were split monthly from May-September. Plots are 3ft by 3ft in size with four species and five cultivars per species being evaluated.

All cultivars seeded at 2 PLS cm-2, using germination data and 1.0 lb of P (0.5 lb N) applied at seeding and 0.5 lb N was applied 2-3 weeks after seeding. All plots were covered with Futtera EnviroNet and irrigated during establishment and once mowing began plots were mowed every 7 days in 2023 at 3.5”. After establishment unless environmental conditions became extreme irrigation was not applied.

Table 1. Seeding dates, turfgrass species and cultivars used during trial focused on refining best management practices for nitrogen applications to cool-season turfgrass lawns across Ohio

Sites	Tall Fescue	Hard Fescue	Kentucky Bluegrass	Perennial Ryegrass
Cincinnati (Blue Ash)	Hemi	Hardtop	Dauntless	Accent II
Columbus (OSU)	Bullseye	Jetty	Aviator II	Fastball 3GL
Wooster (OSU)	Raptor III	Nanook	BlueNote	Overdrive 5G
Findlay (OSU)	Zion	Tenacious	Mercury	Silver Sport
	Rhizing Moon	Minimus	Moonlight SLT	SR4700

Data was collect bi-weekly from April-November at all four sites. Growth was measured in avg daily height using laser distance device (Bosch) and calculated based on time after mowing. Turfgrass health and vigor were evaluated using normalized difference vegetation index (NDVI) (Trimble Inc) while density was analyzed using light box photos and the turf analyzer software. Soil tests were carried out in year 1 and will be carried out again in year two. Weather data is being collected using weather stations (Meter Group) at each location. Soil water potential was quantified and and only irrigate when necessary.

Current Results:

After the conclusion of year 1, there is quite a bit to report. It is pretty clear that the 2N and 4N rates are providing the highest turf quality, but that difference is negligible depending on location. Columbus is providing the highest contrast between N rates while the other 3 locations have more nuanced differences. Early on in year 2, the bluegrass plots have started to shine at the higher N rates and tall fescue is remaining as the most consistent provider of high turf quality across N rates and across locations. While ryegrass was quick to establish and performed well early on, given this “home lawn” scenario with minimal inputs, it has become one of the worst performing species across all locations and N rates, especially during the meat of the growing season. Hard fescues do look really good, but may be running into excessive organic matter accumulation, especially at the higher N rates. Organic matter analysis from year 1 is currently ongoing and will be reported on in a future update.

 

 

 

 

Acknowledgements:

Funding for Project was made possible by the U.S. Department of Agriculture’s (USDA) Agricultural Marketing Service through grant AGR-SCBG-2022-02. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the USDA