Alliance for Low Input Sustainable Turf

National Turfgrass Evaluation Program

2023 National Kentucky bluegrass Test

Join me on field day when I talk about turfgrass weed management issues that I’m seeing or that have been reported to me in 2024. There will also be a station rotation that demonstrates some newer and soon to be registered herbicides that I’ll compare to some industry standards for control of broadleaf weeds. I’ll also show trials that look at combinations of topramezone and quinclorac for control of crabgrass.

This link is to a general guide to herbicides used for turfgrass weed control Turfgrass Weed Control 2024

This link is a guide to broadleaf weed identification Gardner_Broadleaf ID

This link is a guide to grassy weed identification Gardner_Weedy Grass ID

Fertilizer for use on home lawns and high-cut turfgrass sites including sports fields and golf courses has traditionally been synthetic, and that may be providing excess levels of mineral nutrients.  There are concerns over the impact of these fertilizers on water quality following applications to lawns, and the increasing cost of the materials recently used to produce them. Because of this, there is greater interest from homeowners for alternative mineral nutrient sources to apply to their home lawns, and by professional applicators to use in parks or sports fields. This project aims to evaluate the use of soy co–products as an alternative source of mineral nutrients, either in liquid or dry form for fertilization of home lawns and other high–cut turfgrass areas such as sports fields and parks. 

This trial is ongoing at three sites – Wooster, OH Columbus, OH and West Lafayette IN. Treatments have been applied as liquid suspension currently with further work planned in 2025.

Tyler Carr

Assistant Professor and Turfgrass Extension Specialist

Introduction

Turfgrass managers aim for consistent turf growth and color. Nitrogen fertilization is typically used to achieve these goals, but frequent applications of quick-release nitrogen (like urea or ammonium sulfate) can result in uneven growth and color. While “spoon feeding” nitrogen—applying small amounts frequently—can address this, it’s impractical for large turf areas due to high labor costs and the limitations of typical lawn care service schedules. Slow-release fertilizers offer a solution by gradually releasing nitrogen, reducing the need for frequent applications and minimizing the growth spikes associated with quick-release sources.

Slow-release fertilizers reduce the frequency of fertilizer applications per year. However, it remains unclear whether turfgrass can maintain consistent growth and quality with only one or two applications annually compared to four applications of quick-release fertilizers.

Materials and Methods

This experiment was initiated in May 2023 on a mature Kentucky bluegrass lawn and continues through May 2025. The experimental area was mowed at 2.5 inches weekly, with clipping returned. Irrigation was not provided except for four fertilizer applications per year, each followed by a 0.25-inch watering to incorporate the product.

Four nitrogen sources were applied were applied at 2 lb N/1000 ft²/year according to the following structure:

Evaluations:

• Turfgrass color is assessed every two weeks using digital image analysis
• Turfgrass height is measured every two weeks using a Turf Height Tester

Results

Turfgrass color

2023

2024

• All spring applications had color similar to or greater than the standard urea treatment.
• Applying 2 lb N/1000 ft² in a single application resulted in the greatest magnitude of turfgrass color
• Sources differed in their duration of color
• Fall applications in 2023 generally improved color through mid-April 2024.

Turfgrass height

2023

2024

• In 2023, spring treatments at higher nitrogen rates resulted in the greatest magnitude of growth. This growth could be thought of as excessive.
• 1 lb N/1000 ft² treatments in both May and September provided more consistent growth and generally were similar to the standard urea control.
• Fall applications resulted in similar growth in the fall, but had greater growth in the spring.

Conclusions

Current data suggests that a single 2 lb N/1000 ft² of any of the fertilizer sources tested in either spring or fall will likely not provide consistent turf color or growth. However, 1 lb N/1000 ft² in both May and September can reduce fluctuations in color and growth, while providing labor benefits over four applications of urea at 0.5 lb N/1000 ft². Also, since some of the slow-release fertilizers elicit a turf response later than others, custom blends of quick- and slow-release sources can provide more consistent color and growth.

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

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.

Image overview of Columbus plot location with N=400 3’x3’ plots

Active blog site which provides updates and results: https://u.osu.edu/homelawnfertilizer/

Overview of rep 4 at the Columbus location showing the five levels of nitrogen rates color coded by treatment level. Photo taken two weeks after initial fertilizer application. White (0lbs N/M/yr), Blue (0.5lbs N/M/yr), Yellow (1 lbs N/M/yr), Green (2 lbs N/M/yr), and Red (4lbs N/M/yr).

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

Brynn Johnson

Graduate Research Associate, The Ohio State University

Introduction

Increased traffic on community sports fields diminishes turfgrass coverage. To address this issue, this project aims to find the optimal combination of mowing height and nitrogen rate for tall fescue and Kentucky bluegrass under traffic. These turfgrasses were selected since Kentucky bluegrass is the most commonly used turfgrass for recreational sports fields in Ohio, while tall fescue is a lower-input alternative.

This experiment will test three mowing heights and six fertilizer rates over two years, 2024 and 2025. By fine-tuning management practices, we aim to equip sports field mangers with the tools to maintain high-quality turfgrass, despite unpredictable and often excessive use.

Optimizing mowing height and nitrogen rate is crucial as these are controllable factors in an environment where traffic levels are often beyond the sports field manager’s control. This research will help allocate resources efficiently by determining the most cost-effective mowing and fertilization strategies for different turfgrass conditions.

Objective

Determine the effect of mowing height and nitrogen fertilizer rate on the simulated athletic field traffic tolerance of (1) tall fescue and (2) Kentucky bluegrass.

Materials and Methods

• Mowing Program
  • Mowing occurs with a walk-behind rotary mower and clippings are returned
  • 1.5 inch mowing height: mowed on Monday, Wednesday, and Friday
  • 2.5 inch mowing height: mowed on Monday and Friday
  • 3.5 inch mowing height: mowed on Monday
• Fertilizer Program
  • 0, 1, 2, 3, 4, and 5 lb N/1000ft² are applied every two weeks (June-October) and watered in directly afterwards
  • Granular fertilizer was applied in the form of ammonium sulfate (21-0-0)
• Traffic Program
  • Traffic will occur August through October for 10 weeks using a modified Baldree traffic simulator (Toro ProCore 648)
  • These traffic events will occur 3x/week on Tuesday, Wednesday, and Thursday
• Data Collection
  • Data will be collected 1x/week for ten weeks starting in August
  • Turfgrass coverage will be assessed weekly using digital image analysis
  • Surface hardness will be collected weekly using the Clegg Impact Soil Tester (2.25 kg)
  • Rotational resistance will be assessed weekly using a Shear Vane
  • Soil moisture and temperature sensors have been installed at three different points throughout each trial area to continuously monitor these parameters

Expected Results

The objective of this project is to find the optimum combination of mowing heights and nitrogen rate under traffic stress. It is expected that higher amounts of nitrogen will increase green cover, though we do anticipate that there will be a point where additional fertilizer will not improve the quality of the turfgrass. We also expect that the optimal nitrogen rate for traffic tolerance may vary depending on mowing height. Additionally, each species may require different nitrogen rate and mowing height combinations for optimal performance. Overall, we aim to find the best nitrogen rate and mowing height combinations so that sports field managers can allocate their resources efficiently in different conditions.

Introduction

Fine fescue (Festuca spp.) turfgrasses have been shown to be among the most shade tolerant cool-season turfgrasses through anecdotal and scientific evidence (Petrella and Watkins, 2021; https://doi.org/10.1002/csc2.20279). This group of cool-season consists of multiple related species that can often look quite similar, but perform very differently under various types of stresses. The most commonly used fine fescues include strong creeping red (Festuca rubra L. ssp. rubra Gaudin; STF), slender creeping red (F. rubra L. ssp. littoralis (G. Mey.) Auquier; SLF), Chewings (F. rubra L. ssp. commutata Gaudin; CHF), hard (F. brevipila Tracey; HDF), and sheep fescue (F. ovina, L.; SHF).

Most data has indicated that Chewings and strong creeping red fescue cultivars are the most tolerant to foliar-shade (shade from trees and/or shrubs), but that doesn’t mean that other fine fescues are not shade tolerant. Fine fescues are in general extremely variable within species; some Chewings fescue cultivars are great in shade, some are bad; a lot of hard fescues are not the best in shade, but some are great in shade (Figure 1).

Figure 1: All fine fescues are thought to be great in shade, regardless of species or cultivar, this is not true. Some cultivars of the same species are very good under shade while others can be very bad. Choice of fine fescue cultivar under shade may be more important than species itself.

Shade is a very difficult environment for turfgrasses to grow in due to shade consisting of multiple stresses; competition for water and nutrients with trees, higher humidity, cool days followed by warmer nights, reductions in light intensity, alterations in spectral quality – alterations in the color of the light after being filtered by the tree leaves, and sudden exposure to short periods of high-intensity light (sun flecks; dappled shade). All of these stresses make real-world shade research difficult – some plots may be in a very different environment compared to others and results from this trial show this variation.

The objective of this trial was to examine variation in shade tolerance among hard fescue, strong creeping red fescue, and Chewings fescue cultivars under tree shade in Columbus Ohio.

Materials and Methods

Plots were established at the Ohio Turfrgass Foundation (OTF) research and education center on 9/28/18 by Dr. Ed Nangle and Dr. David Gardner. A total of 16 fine fescue entries were evaluated; 6 Chewings fescues, 5 strong creeping red fescues, and 5 hard fescues (Figure 2 and 3). All cultivars were seeded at a rate of 5 lbs. of seed per 1,000 sq. ft.

Starter fertilizer was applied at 1.0 lbs. of nitrogen per 1,000 sq. ft. on 10/2/18 (14-28-10) along with a pelletized paper mulch at 25 lbs. of product per 1,000 sq. ft. No supplemental irrigation was applied at establishment or during the entire trial.

Figure 2: Fine fescue species and cultivars used in this trial.

Figure 3: Layout of fine fescue trial at the OTF center in Columbus Ohio.

Plots were maintained with minimal maintenance and were only mowed once per week at 4.0 inches during 2019 and 2020. Mowing was infrequent to absent during 2021 and plots were not mowed until July 2022.

In 2022, 2023, and 2024 plots have only been mowed 2-3 times per year. Broadleaves were controlled with herbicide in late 2022, and 0.50 lb of N per M has been applied in the spring of each year.

Results and Discussion

As of summer 2024 there were no significant differences in turfgrass density or turfgrass quality between the species and the cultivars used (Figure 4 and 5). However, in summer 2023, Chewings fescues were the most dense species.

This is primarily due to the large amount of variation in the trial. For example, ‘Radar’ Chewings fescue had acceptable turfgrass quality in replicates 1 and 2, but the placement of replicate 3 was in an extreme location leading to a large decline in density and quality – the same for ‘Shademaster III’ strong creeping red fescue.

Figure 4: Turfgrass density and quality for the fine fescues species used in this study from 2022 to 2024.

Figure 5: Turfgrass density and quality for the fine fescues cultivars used in this study from 2022 to 2024.

Fine fescue cultivars showed inconsistent results across all replicates and all years. ‘Aberdeen’ strong creeping red fescue (Figure 6), ‘Marvel strong creeping red fescue, ‘MNHD’ hard fescue, ‘Momentum’ Chewings fescue (Figure 6), and ‘Chantilly’ strong creeping red fescue (Figure 6) were some of the most consistent entries across the last 3 years (7-27-22 Fine fesuce shade plot pictures; 7-27-22 Fine fescue shade trial overhead drone pictures; Fine fescue shade plot pictures 2024).

Turfrgass cover increased for all cultivars and species in 2023. In 2024, all entries performed well during the beginning of summer, but drought led to decline for many cultivars (Figure 5). The most consistent species in this trial was hard fescue, and the only hard fescue to show little change in quality over time was ‘MNHD’. Hard fescues are espically known for their tolerance to drought compared to Chewings and strong creeping red fescue. Hard fescues may have performed the most consistent in this trial becuase of this and due to the fact that plots had very little input.

Figure 6:Drone pictures of plots taken on July 27th 2022.

The way in which these cultivars gained higher visual density and quality varied. Some cultivars had shorter leaves and more tillers to cover the soil surface, while other cultivars had less tillers and longer leaves that laid over to cover the soil. While these cultivars gained shade tolerance differently, the way in which they are managed may make some lose turfgrass quality. For example, cultivars that exhibit shade tolerance from longer leaves that lay over to cover the soil while having less tillers may not maintain high turfgrass quality when mowed at a lower height or when mowed frequently. While cultivars with more tillers and shorter leaves may maintain quality under different management practices.