Author: nangle.1

Photoselective Filters Impact on Turf Quality

by

Photoselective Filters Impact on Turf Quality

D. Petrella, M. Berger, E. Nangle, and T. Morris

Introduction:

Shade management strategies have used multiple approaches which include reductions in nitrogen rates, use of plant growth regulators, management of moisture content (Nangle et. al., 2012) and increases in mowing height as well as removal of trees and plant material surrounding area of importance that help with air movement. Research on shade however has required different approaches based on the portion of the industry that is affected. For example stadium shade or inert structure shade reduces light intensity but does not affect light quality and thus research that reports on use of shade cloth is pertinent for those situations (Russell et al., 2020). Research that focuses on plant (or tree shade) influences have shown that changes in growth habit and physiology are much greater compared to the shade cloth influence (Wherley et al., 2005, Petrella et al., 2020) and thus further work should be conducted with these materials. The reason for this difference is believed to be the reduction in the red far red ratio which occurs due to differential wavelength absorption by tree lines (Bell et al., 2005) The objective of this trial was to evaluate and compare the impact of the two types of shade materials and also investigate if a novel approach of cytokinin application could help alleviate some of the issues. Cytokinin is a plant hormone linked to enhanced cellular division as well as a promoter of branching and root growth and so this may offer a solution to aid in retention of turf quality..

Materials and methods:

This trial was established at three locations (2 in Wooster OH; 7-1-23 and 1 in Columbus; 7-6-23). Two of the surfaces consisted of newly established S-1 creeping bentgrass Agrostis stolonifera and the other surface was a mixed stand of annual bluegrass Poa annua and creeping bentgrass. Mowing heights were 0.130″ in Wooster and 0.150″ in Columbus. Surfaces were given approx approx 1.5lbs N to date in 2023 and fungicides were applied in a preventative manner. Growth regulator was applied only to the mixed annual bluegrass and creeping bentgrass stand every 14d at a rate of 12 fl oz/ acre of trinexapac ethyl. Data were collected for turf quality and normalized difference vegetation index as well as images collected using a photobox. MaxCell a synthetic cytokinin was applied on 7/12/23 at a concentration of 2.54 µmol. Data were collected for light intensity and light quality also. Light quality data indicated full sun R:FR of approx 1.2-1.3, Shade cloth R:FR was measured between 1 and 1.2 (plants respond above 1 similar to full sun) and the filters were measured at 0.2.

Results:

The impact of the filters was clearly noted on the more established plots in Wooster OH with a faster and more severe negative response to the change in light quality. The application of the cytokinin based product (not currently labelled for turf) did not provide immediate improvement and there may be a need to evaluate the product from a rate standpoint. Currently the recommendations for reducing nitrogen inputs, use of plant growth regulators, closely monitoring irrigation requirements and, selective pruning and  tree removal where possible are all approaches that should be implemented to aid with maintenance of turfgrass quality during the heavy summer paying season.

Impact of photoselective filters on turf quality and applications of MaxCell to ‘S-1’ Creeping bentgrass summer 2023, Columbus OH

Treatment D2 D20
 Shade Cloth 3.5 a† 3.5 ab
Photoselective Filter 2.2 b 2.7 b
Full sun 2.5 b 3.9 a
LSD 0.8 1.1

†Means followed by different letters are significantly different at p<0.05

 

 

Impact of photoselective filters and applications of MaxCell on NDVI values of ‘S-1’ Creeping bentgrass summer 2023, Columbus OH

Treatment D2 D20
Shade Cloth 0.573 a† 0.472 b
Photoselective Filter 0.573 a 0.473 b
Full Sun 0.548 a 0.542 a
LSD 0.048 0.048

†Means followed by different letters are significantly different at p<0.05

Figure 1. Plot plan for trial evaluating Impact of photoselective filters and applications of MaxCell on NDVI values of ‘S-1’ Creeping bentgrass summer 2023, Columbus OH

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

References:

Bell, G.E., Danneberger, T.K. and McMahon, M.J. (2000), Spectral Irradiance Available for Turfgrass Growth in Sun and Shade. Crop Sci., 40: 189-195. https://doi.org/10.2135/cropsci2000.401189x

Nangle, E. J., Gardner, D. S., Metzger, J. D., Street, J. R., & Danneberger, T. K. (2012). Impact of Nitrogen Source and Trinexapac-ethyl Application on Creeping Bentgrass (Agrostis stolonifera L.) Physiology under Neutral Shade, Deciduous Tree Shade, and Full Sunlit Conditions. HortScience horts, 47(7), 936-942.  https://doi.org/10.21273/HORTSCI.47.7.936

Petrella DP, Breuillin-Sessoms F, Watkins E. (2022) Layering contrasting photoselective filters improves the simulation of foliar shade. Plant Methods. Feb 8;18(1):16. doi:10.1186/s13007-022-00844-8

Russell, TR, Karcher, DE, Richardson, MD. (2020) Daily light integral requirements of warm-season turfgrasses for golf course fairways and investigating in situ evaluation methodology. Crop Science. 60: 3301– 3313. https://doi.org/10.1002/csc2.20234
Wherley, B.G., Gardner, D.S. and Metzger, J.D. (2005), Tall Fescue Photomorphogenesis as Influenced by Changes in the Spectral Composition and Light Intensity. Crop Science, 45: 562-568. https://doi.org/10.2135/cropsci2005.0562

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

by

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 analzyzed using light box photos and the turf analyzer software. Soil tests were carreid 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.

Results:

Hard fescues and Kentucky bluegrasses failed to establish in Wooster; Hardtop was the best-established hard fescue in Wooster. Tall fescue is performing surprisingly poor in Findlay, regardless of the nitrogen applied. Kentucky bluegrass did not establish well at either of the Columbus or Blue Ash locations, Tall fescue is the top performer thus far at these two locations. Color differences across all cultivars is the most notable among the different nitrogen rates, especially with the Hard fescues.

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

 

 

The impact of No Mow May on pollinator numbers and turfgrass quality

by

The impact of No Mow May on pollinator numbers and turfgrass quality

E. Nangle D. Petrella T. Morris S. Cusack

Introduction:

No Mow May is an effort to increase pollinator number and diversity in homelawns focused on not mowing a lawn through the month of May. The idea originated in the United Kingdom and gained momentum in the United States after work published in Wisconsin (Del Toro and Ribbons, 2020) (now retracted) indicated potential benefits from this practice. Creation of areas that have greater amounts of flowering has been shown to increase pollinator levels (Blau and Isaacs, 2014; Billeisen et al., 2022) alongside maintained areas but the theory that simply not mowing a lawn will have the same effect has to date been untested. The objective of this particular trial was not to evaluate pollinator diversity but rather evaluate simply pollinator numbers as well as the impact of the practice on a home lawn and there were multiple hypotheses, firstly a traditionally maintained homelawn will not see any increase in pollinator numbers, the impact on the lawn through the summer may lead to undesirable effects and finally there may be difficulty in returning the lawn to its previous condition upon completion of the period.

Materials and Methods:

The trial was carried out on three different sites, two located in Wooster OH and one located in Columbus OH. Treatments were initiated on approximately on Apr 28 when all sites were mowed to a uniform height of 3″ and marked out. Plots were set up in a randomized complete design at all three sites with four replications per sites. Treatments consisted of a variety of mowing regimes throughout the summer period including the limitation of mowing during the month of May (Table 1). Plots were 10ft x 5ft in size to allow for commercial mowing decks to pass across the surface with a 5ft border around all plots and between reps. Prior to initiation of treatments treatments were evaluated for color (1-9 scale 6=acceptable 9 = dark green 1 = brown/dead), turf density (1-9 scale 6 = acceptable 9 = no soil visible 1 = bare soil 6 =acceptable), Weed cover (percent of plot), Pollinator count (5min timed counts occuring between 12-4pm on a date prior to the trial, during the trial and at the end of the trial). Turf height was measured using a laser height measurement tool (Bosch) and this occurred at trial completion.

Mowing was resumed on June 2 (Wooster) or June 5 (Columbus) and regimes were installed in regard to how a return to a desired 3″ mowing height would occur. Mowing in Wooster used

Table 1. Treatments used during trial evaluating impact of No Mow May on pollinator numbers and turfgrass quality

Treatment
1 June 1– Mow plot back to previous height – 3” and remain mowing biweekly at this height for 2 months
2 June 1 – Mow Plot back to 5” June 15 Mow back to 4” June 29 Mow back to 3” mowing biweekly at this height for 2 months
3 June 1 – Mow Plot back to 5” June 15 Mow at 5” June 29, Mow at 4”, July 13 Mow down to 3” and continue at this bi weekly until trial completion
4 Mowing maintained throughout the period of May at 3” height and continued through rest of trial period biweekly
5 June 1 – Mow plot back to 4” June 15 – Mow back down to 3” mowing biweekly at this height for 2 months

 

Results:

Climatically it was a dry period of the year that the evaluation occurred. The monthly rainfall amounts for Columbus were 0.3″ below normal while the area was considered to be abnormally dry. This impacted turfgrass growth by limiting the amount of biomass that was accumulated. On average however in the plots that received no mowing there was a height 16″.

Wooster Maintained lawn data

Turf density and color showed some variability in Wooster on what might be considered a traditionally maintained home lawn and once conditions became warmer and drier later in the trial all plots exhibited declines in color. On the final rating date treatments 2 and 3 showed a significant loss of color (Table 2) compared to all other treatments. Density ratings were much above acceptable during the trial for all treatments until D56 after initiation when a return to mowing and increased temperature lead to a decline in turf density (Table 3).

Table 2. Daily color ratings (1-9) during evaluation of impact of No Mow May on turfgrass and pollinator numbers during Summer 2023 in Wooster, OH.

Treatment D0 D28 D41 D56 D67 D81
1 7.4 a† 6.1 a 6.6 a 6.5 a 5.8 a 5.9 a
2 7.4 a 6.5 a 6.5 ab 6.1 b 3.9 b 4.4 b
3 7.4 a 6.3 a 6.6 a 6.3 ab 4.1 b 4.1 b
4 7.5 a 6.1 a 6.1 b 6.3 ab 5.8 a 5.5 a
5 7.4 a 6.6 a 6.4 ab 6.3 ab 4.4 ab 5.5 a
LSD 0.4 0.5 0.5 0.3 1.4 0.9

† Means followed by different letters are significantly different at p<0.05

 

Table 3. Daily density ratings (1-9) during evaluation of impact of No Mow May on turfgrass and pollinator numbers during Summer 2023 in Wooster, OH

Treatment D0 D28 D41 D56 D67 D81
1 8.4 a† 8.5 b 6.5 ab 6.3 ab 5.8 a 5.6 a
2 8.4 a 9.0 a 6.4 ab 6.3 ab 5.8 a 5.5 ab
3 8.3 a 8.9 ab 6.6 a 6.4 a 5.8 a 5.3 b
4 8.5 a 8.5 b 6.1 b 5.9 b 5.8 a 4.8 c
5 8.1 a 8.9 ab 6.4 ab 5.9 b 5.9 a 5.4 ab
LSD 0.6 0.4 0.5 0.5 0.6 0.4

† Means followed by different letters are significantly different at p<0.05

Not mowing had no impact on weed development and hence limited amounts of flowering could occur (Table 4).

Table 4. Daily percent weed cover ratings during evaluation of impact of No Mow May on turfgrass and pollinator numbers during Summer 2023 in Wooster, OH

Treatment D0 D28 D41 D56 D67 D81
1 0.0 a† 0.0 a 0.0 a 0.0 a 0.0 a 0.0 a
2 0.25 a 0.25 a 0.25 a 0.25 a 0.25 a 0.25 a
3 0.0 a 0.0 a 0.0 a 0.0 a 0.0 a 0.0 a
4 0.0 a 0.0 a 0.0 a 0.0 a 0.0 a 0.0 a
5 0.0 a 0.0 a 0.0 a 0.0 a 0.0 a 0.0 a
LSD 0.3 0.3 0.3 0.3 0.3 0.3

† Means followed by different letters are significantly different at p<0.05

The timed counts provided limited information and no regime or treatment provided higher levels of pollinators in this site.

Daily pollinator count numbers during evaluation of impact of No Mow May on turfgrass and pollinator numbers during Summer 2023 in Wooster, Ohio.

Treatment D0 D28
1 0.0 a† 0.5 a
2 0.0 a 0.5 a
3 0.0 a 0.5 a
4 0.0 a 0.0 a
5 0.0 a 0.5 a
LSD 0.0 1.1

† Means followed by different letters are significantly different at p<0.05

 

Daily color ratings (1-9) during evaluation of impact of No Mow May on turfgrass and pollinator numbers during Summer 2023 Columbus Ohio.

Treatment D0 D7 D35 D49 D69
1 6.8 a† 7.0 b 6.5 b 7.0 bc 6.3 a
2 7.3 a 7.5 ab 7.3 ab 7.4 b 6.0 a
3 7.0 a 7.5 ab 7.8 a 8.0 a 6.5 a
4 6.3 a 8.0 a 7.0 ab 7.3 b 6.5 a
5 7.3 a 7.6 ab 7.3 ab 6.8 c 6.8 a
LSD 1.8 0.9 1.0 0.5 1.0

† Means followed by different letters are significantly different at p<0.05

 

Daily density ratings (1-9) during evaluation of impact of No Mow May on turfgrass and pollinator numbers during Summer 2023 in Columbus, Ohio.

Treatment D0 D7 D35 D49 D69
1 6.5 a† 7.0 a 6.8 a 8.0 a 7.3 a
2 7.0 a 7.0 a 6.8 a 7.8 a 7.3 a
3 6.0 a 7.3 a 7.0 a 7.3 a 7.3 a
4 6.5 a 6.8 a 6.5 a 7.5 a 7.3 a
5 6.5 a 6.5 a 6.8 a 7.3 a 7.5 a
LSD 2.5 1.2 1.3 1.0 1.2

† Means followed by different letters are significantly different at p<0.05

 

Daily percent weed cover ratings during evaluation of impact of No Mow May on turfgrass and pollinator numbers during Summer 2023 in Columbus, Ohio.

Treatment D0 D7 D35 D49 D69
1 47.5 a† 45.0 a 32.5 a 37.5 a 45.0 a
2 47.5 a 42.5 a 45.0 a 42.5 a 40.0 a
3 42.5 a 47.5 a 45.0 a 47.5 a 42.5 a
4 37.5 a 37.5 a 32.5 a 42.5 a 47.5 a
5 50.0 a 45.0 a 42.5 a 47.5 a 57.5 a
LSD 22.7 12.0 20.9 26.2 28.4

† Means followed by different letters are significantly different at p<0.05

 

Daily pollinator count numbers during evaluation of impact of No Mow May on turfgrass and pollinator numbers during Summer 2023 in Columbus, Ohio.

Treatment D0 D7 D35 D49
1 0.0 a† 0.0 a 0.0 a 0.0 a
2 0.0 a 0.0 a 0.0 a 0.0 a
3 0.0 a 0.0 a 0.0 a 0.0 a
4 0.0 a 0.0 a 0.0 a 0.0 a
5 0.0 a 0.0 a 0.0 a 0.0 a
LSD 0 0 0 0

† Means followed by different letters are significantly different at p<0.05

 

Conclusions:

While the trial provided a range of interesting data, concerns would arise regarding the efficacy of the program. Unless wildflowers or similar are established in a lawn and premergent herbicides are not used then it is hard to see how much flower development can occur in suburban home lawns that might be maintained in this way. Further to this many weeds such as purple dead nettle and clover will flower at height of 2-3″ thus not mowing for a month seems fruitless. The lawns that had less long term maintenance did not provide dramatically high insect numbers and this was also of interest. Finally, anecdotally in the Cleveland area the day after the trial it was noted that clover flowered. Options going forward include communication with homeowners as well as understanding what homeowners wants are – as it may be that half a lawn is enough to sustain a bee population.

 

References:

Billeisen, T.L. Kilpatrick, L.D. Seth-Carley, D. & Brandenburg, R.L. 2022. Presence of pollinator-friendly habitat on pollinator communities in managed turfgrass systems. Int Turfgrass Soc Res J. 2022; 14: 295– 303. https://doi.org/10.1002/its2.56

Blaauw, B.R. and Isaacs, R. (2014), Flower plantings increase wild bee abundance and the pollination services provided to a pollination-dependent crop. J Appl Ecol, 51: 890-898. https://doi.org/10.1111/1365-2664.12257

Del Toro, I., & Ribbons, R. R. (2020). No Mow May lawns have higher pollinator richness and abundances: An engaged community provides floral resources for pollinators. PeerJ, 8, e10021. https://doi.org/10.7717/peerj.10021

 

Biostimulants and Drought Tolerance – what have we learned over the two years.

by

Biostimulants and Drought Tolerance – what have we learned over the two years.

E.J. Nangle T. Morris, S. Cusack and D.P. Petrella

Introduction:

The use of biostimulants in turfgrass management is becoming more critical to the success of turfgrass managers as environmental stresses increase and limitations are continulaly expanded on what can be used in golf course settings. The consistency of the results obtained can however leave turfgrass managers with pause for concern . Issues such as variations in soil types, site specificity and variations in organic matter content, unclear pathways of plant uptake are components of the products that can impact the efficacy of these products. Results have been successful where products have had combinations of nitrogen included in the product and also in laboratory settings indicating there is potential for their use – however field applications have been where the conundrum arises.

One area that is going to be continually a concern for turfgrass managers is the ability to manage turfgrass surfaces with limited levels of moisture to sustain high quality turfgrass surfaces . Products such as wetting agents can help with soil issues that might arise but options for drought tolerance include breeding and potentially use of C4 grass species if conditions continue to deteriorate. The objective of this trial was to evaluate the use of a group of products that are commonly called biostimulants which offer potential solutions in regards to plant hormone changes, stress tolerances and a range of other issues. To compare these products against each other is a regular occurrence but evaluation of these products agaisnt an alternative approach such as the use of Urea also is required based on budget and potential return on investment.

Materials and Methods:

This trial was initiated in its second year at the Waterman Farm in Columbus Ohio on June 8th 2023 on a research green surface that contained a mixed stand of annual bluegrass Poa annua and creeping bentgrass Agrostis stolonifera. The green is mowed at 0.145″ 4x per week with clippings collected and received preventative applications of insecticides and fungicides. Applications were made on June 23rd, July 5th and July 19th using a back pack CO2 sprayer at high label rates for all products (Table 1).

Table 1. Treatments and rates for products used in evaluation of biostimulants for drought tolerance during Summer 2023 in Columbus, OH.

The treatments were replicated four times and laid out in a randomized complete block design (Figure 1). Drought stress was initiated on July 12 with the construction of a framed rainout shelter that was covered with polyethylene liner which was opened on the north and south end to allow for air movement. The drought period was completed on July 24th when hand watering was returned. Turf was evaluated for quality (1-9 scale), color (1-9 scale), percent stress on the plots, normalized difference vegetative index and volumetric water content at 3″ depth. Treatments will be made one final time and recovery will be evaluated through August 31st 2023.

Figure 1. Plot design for trial evaluating impact of Biostimulants on drought stress, Summer 2023, Columbus OH

 

Results:

Color ratings indicated some minor differences initially with treatments 3,4,6 and 8 having a slightly higher color rating but 0.2 difference overall would seem to be of limited consequence. At D27 variability increased but none of the treatments provided color rankings significantly higher than the check plot (9) (Table 2).

Table 2. Daily color ratings during evaluation of biostimulants for enhancement of tolerance to drought stress in Columbus OH, Summer 2023

Treatment D0 D15 D27 D41 D48
1 7.0 a† 6.6 bc 6.8 abc 6.6 bc 6.8 ab
2 6.8 b 6.5 b 6.6 bc 6.4 c 6.4 abc
3 7.0 a 6.6 bc 6.9 ab 7.0 ab 7.0 a
4 7.0 a 6.9 ab 6.9 ab 7.0 ab 6.0 c
5 6.9 ab 6.6 bc 6.5 c 6.8 abc 6.5 abc
6 7.0 a 7.0 a 7.0 a 7.1 a 6.9 a
7 6.9 ab 7.0 a 6.9 ab 6.8 abc 6.1 bc
8 7.0 a 6.8 ab 6.9 ab 7.1 a 6.8 ab
9 6.9 ab 6.6 b 6.8 abc 6.5 c 6.1 bc
LSD 0.2 0.3 0.3 0.4 0.6

†Means followed by different letters are significantly different at p ≤ 0.05

Turf quality with the exception of the final rating date was found to be acceptable for all treatments. On the final date treatment 4 provided an overall ranking that was below acceptable and across all treatments there was some decline in quality. Highest rated treatments were 1,6 and 8 for the final date (Table 3).

Table 3. Daily Quality ratings during evaluation of biostimulants for enhancement of tolerance to drought stress in Columbus OH, Summer 2023

Treatment D0 D15 D27 D41 D48
1 7.0 a† 6.5 a 6.8 abc 6.8 ab 6.6 ab
2 7.0 a 6.4 ab 6.8 abc 6.5 b 6.4 abc
3 6.9 ab 6.4 ab 6.8 abc 7.0 a 6.6 ab
4 6.9 ab 6.5 a 7.0 a 6.8 ab 5.9 c
5 6.6 b 6.6 a 6.8 abc 6.6 b 6.4 abc
6 6.8 ab 6.6 a 6.9 ab 7.0 a 6.9 a
7 6.9 ab 6.1 b 6.5 c 6.8 ab 6.0 c
8 7.0 a 6.6 a 6.9 ab 7.0 a 6.9 a
9 6.9 ab 6.1 b 6.9 ab 6.6 b 6.1 bc
LSD 0.3 0.4 0.3 0.3 0.5

†Means followed by different letters are significantly different at p ≤ 0.05

NDVI values showed some variability at D15 and that pattern continued through D48 when plots were under the most drought stress. Treatment 7 provided significantly lower values along with treatment 9 and 2 on D41 while treatments 3,6 and 8 were rated significantly higher than four other treatments on that date (Table 4).

Table 4. Daily NDVI Ratings during evaluation of biostimulants for enhancement of tolerance to drought stress in Columbus OH, Summer 2023

Treatment D0 D15 D27 D41 D48
1 0.728 ab† 0.772 bc 0.758 bcd 0.776 ab 0.663 ab
2 0.722 b 0.772 abc 0.742 d 0.757 de 0.638 bc
3 0.736 a 0.788 a 0.762 abc 0.785 ab 0.690 a
4 0.737 a 0.780 ab 0.766 abc 0.771 bcd 0.600 cd
5 0.725 ab 0.777 abc 0.754 bcd 0.762 cde 0.653 ab
6 0.727 ab 0.787 ab 0.769 ab 0.783 ab 0.700 a
7 0.721 b 0.769 c 0.748 cd 0.747 e 0.585 d
8 0.731 ab 0.783 abc 0.775 a 0.791 a 0.703 a
9 0.726 ab 0.777 abc 0.753 bcd 0.762 cde 0.638 bc
LSD 0.014 0.016 0.018 0.017 0.052

†Means followed by different letters are significantly different at p ≤ 0.05

Stress did not develop until D41 which was 7 days after drought was initiated and on both dates (D41 and D48) percent of stressed turf increased. Treatments of Urea att he highest rate provided plots with the lowest levels of stress and this was significantly lower than many of the other treatments. The lower rate of urea also began to show stress at D48 while plots receiving treatments 2,7 and 9(UTC) showed greater stress to the drought (Table 5).

Table 5. Daily stress ratings (% plot) during evaluation of biostimulants for enhancement of tolerance to drought stress in Columbus OH, Summer 2023

Treatment D0 D15 D27 D41 D48
1 0.0 a† 0.0 a 0.0 a 3.1 a 7.5 bc
2 0.0 a 0.0 a 0.0 a 2.5 ab 27.5 a
3 0.0 a 0.0 a 0.0 a 0.0 b 8.1 bc
4 0.0 a 0.0 a 0.0 a 0.0 b 10.0 ab
5 0.0 a 0.0 a 0.0 a 1.3 ab 7.5 bc
6 0.0 a 0.0 a 0.0 a 0.0 b 8.1 bc
7 0.0 a 0.0 a 0.0 a 2.5 ab 26.3 ab
8 0.0 a 0.0 a 0.0 a 0.0 b 4.4 c
9 0.0 a 0.0 a 0.0 a 1.9 ab 21.3 ab
LSD 0.0 0.0 0.0 2.9 19.3

†Means followed by different letters are significantly different at p ≤ 0.05

 

Conclusions:

In 2022, treatment #7 provided turf quality as high as the urea treaments but this did not happen in 2023. The additional rate of urea showed a dose response in the sense that the lower rate showed increased stress during the drought period. Recovery data will be collected and analyzed for both years to complete this study. The products used other than urea currently cannot form a stand alone program for drought stress and should only be used in combination with other agronomic practices.

Welcome

by

 

 

Welcome,

This site serves for reports from past, current and future turfgrass field day research at The Ohio State University – feel free to use this at any time and if you have questions reach out to the researcher linked to the specific data.

Thanks and go bucks!

Biostimulants and their impact on drought stress in Ohio during Summer 2022

by

Biostimulants and their impact on drought stress in Ohio during Summer 2022.

 

E.J. Nangle1, T Morris1, D.P. Petrella1 S. Cusack2, B. Stith2.

1OSU CFAES Wooster Campus, 1328 Dover Rd, Wooster 44691

2OSU Turfgrass Research Facility, 2710 Northstar Road Columbus OH 43221

 

Introduction:

Drought stress has become an increased problem for turfgrass managers both in Ohio and across the Midwest with excessively dry periods combined with heat leading to large volumes of water use and concerns about turfgrass quality on high value surfaces. Traditionally golf course superintendents have relied on judicious use of fertility and water management combined with reductions in agronomic inputs to retain turf quality. Recently however with newer turfgrass cultivars emerging for putting greens and ever lower mowing heights there is added pressure to find extra roll and smoothness which has led superintendents to investigate the use of a class of products known broadly as ‘biostimulants’. Further to this, potential changes in legislation may begin to see curbs on pesticide applications. There is a two-fold need then to look more closely at these products and evaluate where they might fit into the golf course managers tool box and also compare these products against what might be considered traditional agronomic practices.

 

Materials and Methods:

This trial was initiated at the Ohio State University Turfgrass Research Facility in Columbus OH on June 9th 2022. Treatments were then applied on June 23rd, July 7th and July 21st. The trial was placed on a pushup rootzone with mixed annual bluegrass Poa annua creeping bentgrass Agrostis palustris cv. ‘Penncross’ stand. There were eight treatments with four replications, and they are shown in Figure 1. The treatments were laid out in a randomized complete block with dimensions of 0.91m x 1.83m. Treatments were applied using a CO2 backpack sprayer with a carrier volume of 300 L/ha. Treatments were applied for all products at the high label rate (Table 1). Plots were mowed daily at a height of 4.3 mm with clippings collected until the second week of the drought study when plots were only mowed twice.

All areas received current environmental conditions prior to July 13th 2022, with a last wetting agent application made on June 8th and preventative insecticide and fungicide treatments made through out the duration of the trial. On July 12th all supplemental irrigation was removed and a rain out structure was installed to prevent any external rainfall landing on the surface. This allowed for no water to be applied to the research surface for 16 days in total. On July 28th irrigation was applied to a depth of 2.45 cm on all plots and on July 30th irrigation was applied to a depth of 1.25cm.

During the trial color ratings were taken on a weekly basis on a 1-9 scale with 6 = acceptable. Normalized difference vegetation index (NDVI) data were collected as well as images collected using an NDVI camera weekly, stress on the plot (% of turf stressed) and turf quality with voids and loss of density being the main focus (1-9 scale with 6 = acceptable). During the dry down period firmness (depth of penetration in cm) (Spectrum Technologies, Trufirm) and soil moisture readings (% volumetric water content) Spectrum Technologies, TDR 300.

Five days post rewatering turf color, quality, percent stress and NDVI values were collected and analyzed. Data were analyzed using SAS 9.4. Weather data was collected at the site using a Campbell Scientific weather station.

A second trial site in Creston OH at Hawks Nest GC on a creeping bentgrass cv. ‘Pure Distinction’ putting green was run with the same methodology with the only differences being species type, rootzone construction and mowing height on the sites.

Figure 1. Plot layout with treatments and rates for treatments used in a trial evaluating biostimulants and their impact on drought stress in Ohio in the summer of 2022.

Treatment 5 Cytogro – .4 Floz/M = 1.1mL/1L
1 Griggs Bros Carboplex 6-4-4 – 6 Floz/M = 16mL/1L 6 Urea .1N/M = 9g/1L
2 Foliar Pak Foundation Forty 4-0-8 – 3 Floz/M = 7.9mL/1L 7 Harrells Bio Max Root Enhancer Iron (5%) plus Fulvic Acid – 6 Floz/M = 16mL/1L
3 Plant Food Co. Green T Impulse 6-0-0 – 9 Floz/M = 23.9mL/1L 8 Untreated
4 Progressive Turf Greater Green 5-0-7 – 12.8 Floz/M = 34.1mL/1L

 

Results:

 

Climatically conditions were both warm enough and dry enough to lead to drought stress occurring on the plots (Figure 2,3 and 4). Of interest was the relative humidity with average numbers at 50% or lower for an extended period during mid – late June (Figure 3).

 

Figure 2. Daily high temperatures Columbus OH during trial evaluating biostimulants and their impact on drought stress in Ohio in the summer of 2022.

Figure 3. Daily high temperatures in Columbus OH during trial evaluating biostimulants and their impact on drought stress in Ohio in the summer of 2022.

Figure 4. Average daily percent relative humidity in Columbus OH during trial evaluating biostimulants and their impact on drought stress in Ohio in the summer of 2022.

Quality ratings indicated that during the period where there was no limitation on irrigation or rainfall that there was very little difference between treatments. On D28 Urea provided significantly higher quality turf (p=0.05) than a majority of the treatments (Table 1). At D35 when drought stress was initiated urea was again rated amongst the highest treatments along with Harrells BioMax Root Enhancer, Plant Food Co. Green T impulse although only Urea was significantly higher than any of the other treatments (1,2,5,8). Ten days after drought initiation turf was all ratred above acceptable with minor differences being noted. At D52 all treatments showed a decline and only Harrells BioMax Root Enhancer, Urea and Plant Food Co. Green T Impulse were considered above acceptable quality (Table 1). There was no significant difference however between treatments at this time.

Table 1. Daily quality ratings for treatments during trial evaluating biostimulants and their impact on drought stress in Ohio in the summer of 2022.

†Means followed by different letters are significantly different at p=0.05

*Date rainout shelter was installed

Color ratings indicated that through D14 no differences existed while on D21 after initiation Urea rated highest with Harrells BioMax next and all other treatments rated significantly lower (p=0.05). At D35 prior to drought initiation greater variability existed with Urea, Progressive Turf Greater Green and Harrells BioMax providing the highest rated treatments. Only Harrells BioMax and Urea however were significantly higher (p=0.05) than the check plot. Ten days after initiation of the drought all treatments were the same and above acceptable color. D52 the final day of the drought stress showed a decline in some color with four treatments just below acceptable on average while Plant Food Co. Green T, Cytogro, Urea and Harrells BioMax providing turf color above acceptable with all others at or below that rating (Table 2).

Table 2. Daily color ratings for treatments during trial evaluating biostimulants and their impact on drought stress in Ohio in the summer of 2022.

†Means followed by different letters are significantly different at p=0.05

*Date rainout shelter was installed

Evaluations of stress development including wilt, loss of density and color indicated no issues arose until D45 which was 10 days after drought initiation. On that date Foundation 40 rated significantly higher than the Urea plots but not significantly different from any of the rest of the plots. On the final day of the trial Griggs Carboplex had on average 26.9% stress on the plots which was significantly higher (p=0.05) than both Urea and Harrells BioMax treatments (Table 3).

Table 3. Average percent of stress showing on plots for treatments during trial evaluating biostimulants and their impact on drought stress in Ohio in the summer of 2022.

†Means followed by different letters are significantly different at p=0.05

*Date rainout shelter was installed

 

Firmness data indicated that there were no differences between treatments on the final day of the drought study while some variability existed between treatments in regard to moisture. The untreated check had the lowest moisture ratings along side Progressive Turf treatments while Foliar Pak, Urea and Cytogro were found to have the highest moisture content, and this was significantly higher (p=0.05) than the check and Progressive turf only (Table 4).

Table 4. Volumetric water content and firmness readings on final day of drought study during trial evaluating biostimulants and their impact on drought stress in Ohio in the summer of 2022

†Means followed by different letters are significantly different at p=0.05

Conclusions:

This trial has shown that there is potential for some of these products to offer turf managers help during stressful periods. The application of urea however did act in a comparable manner to many of the treatments which was somewhat surprising. It must be noted of course that the urea rate was marginally higher than many of the treatments but is also an industry standard rate. Drought stress, heat stress and other environmental stresses are going to continue to occur and with greater frequency, turfgrass managers, researchers and companies are going to have to work together to utilize all tools available and thus these products deserve further attention and also different methods of analysis. It is expected this work will continue to run for many summers to come on a range of cultivars and soil types.

OSU Turfgrass Research and Education Field day

by

Thank you for visiting the exclusive turfgrass research and education field day website. This site is going to give you access to research reports for this years activities and information related to any education that you will see during the field day. Please feel free to browse the content but the aim is to try and use each QR code from each stop the give you access to content specific to each stop.

We hope this helps you enjoy the day a little more and if there are any questions dont hesitate to reach out to us!