Max Schlossberg, Ph.D. Penn State University • mjs38@psu.edu
Pennsylvania Turfgrass Associate Editor
President Tom Fisher
Wildwood Golf Club – Allison Park, PA (412) 518-8384
Vice President
Rick Catalogna Harrell’s Inc Territory Manager (412) 897-0480
Secretary-Treasurer
Shawn Kister
Longwood Gardens, Inc. –Kennett Square, PA (484) 883-9275
Past President
Pete Ramsey
Range End Golf Club – Dillsburg, PA (717) 577-5401
Director of Operations
Tom Bettle
Penn State University
Assistant Director of Operations
Nicole Kline
Pennsylvania Turfgrass Association
Directors
Steve Craig Centre Hills Country Club
Tanner Delvalle
Penn State Extension
Elliott Dowling USGA
Andy Moran University of Pittsburgh
Tim Wilk
Scotch Valley Country Club
Matt Wolf
Penn State University
Aerate and Play Right Away!
Decreased down time, increased revenue.
The surface is very “puttable.”
The dots are sand that is level with the turf.
DryJect® is a high-pressure, water based injection system that blasts holes through the root zone and fractures the soil profile. Plus, it automatically fills holes as it aerates.
DryJect®
TIPPING POINT
“It’s hard to find help these days.”
“These kids just don’t know how to work!”
“My generation would work every day of summer vacation.”
Hang out long enough in the right maintenance shops and you’ll hear these lines parroted from every corner of The Commonwealth. Aside from the nationwide economic fishbowl we find ourselves in, acquisition and management of our employees remains one of the greatest challenges we face as turfgrass managers. The generational divide between management and employees seems to have hit a tipping point and if it hasn’t yet for you, it will.
Our longing for the good old days is like a cup that can never be filled enough. The benefit of hindsight bronze plates our formative experiences and codifies the daily routine that we consider second nature. Your “Second Nature” is somebody’s first day of a summer job (or budding career in Turf Management); providing an encouraging environment could be the nudge that a young borderline employee needs to show up every day and thrive.
Like every generational epoch, it’s hard to suggest that The Kids are Alright. Statistically speaking, we’ve all burned the social/professional candle at both ends, letting our personal lives intertwine with our careers (McNitt 2006). You’ve probably upset a manager or three somewhere along the way, and if you really knew your stuff, challenged a direct supervisor on whose “Second Nature” was better. On the other end of each one of those interactions was at least one stakeholder, working with you to ensure the grass was still alive at the end of the day. Somebody took a chance on you, had patience with you and if you don’t believe that, your narcissism is showing.
Of course blind faith and excessive generosity are the bricks that pave the road to Hades, but much like your fledging employees, responsibility precedes privileges. Managerial responsibility keeps your seat cool and comfortable; recognizing and rewarding an employee’s work when earned is a bargain.
“Garbage in, Garbage out” is an axiom in the structured world of computer engineering, but fully applies to so many aspects of our ever so fluid careers. When you feel like you’ve had enough of an employee doing a less than perfect job on their task, consider whether you did a less than perfect job of instructing, communicating your expectations, and following through to completion? If we want to ask ourselves what today’s employees are truly capable of, we must first ask ourselves “Who are you?”
Senior Instructor in Turfgrass Weed Management 814-865-3005 • jborger@psu.edu
Michael A. Fidanza, Ph.D. Professor of Plant & Soil Science 610-396-6330 • maf100@psu.edu
David R. Huff, Ph.D. Professor of Turfgrass Genetics 814-863-9805 • drh15@psu.edu
Brad Jakubowski Instructor of Plant Science 814-865-7118 • brj8@psu.edu
John E. Kaminski, Ph.D. Professor of Turfgrass Science 814-865-3007 • jek156@psu.edu
Peter J. Landschoot, Ph.D. Professor of Turfgrass Science 814-863-1017 • pjl1@psu.edu
Ben McGraw, Ph.D. Associate Professor of Turfgrass Entomology 814-865-1138 • bam53@psu.edu
Andrew S. McNitt, Ph.D. Professor of Soil Science 814-863-1368 • asm4@psu.edu
Max Schlossberg, Ph.D. Associate Professor of Turfgrass Nutrition / Soil Fertility 814-863-1015 • mjs38@psu.edu
Al J. Turgeon, Ph.D. Professor Emeritus of Turfgrass Management aturgeon@psu.edu
Wakar Uddin, Ph.D. Professor of Plant Pathology 814-863-4498 • wxu2@psu.edu
Chlorpyrifos:
The Uncertain Future of the Controversial Insecticide and Implications for
Turfgrass Management
By Ben McGraw, Ph.D.
There have been more changes to the turfgrass insecticide landscape over the last 12–18 months than any other time that I can remember in my career. Many of the changes have been good ones for turfgrass managers in Pennsylvania (and much of the country) as new active ingredients have been registered, including a new anthranilic diamide (tetraniliprole (IRAC = 28), Tetrino®, Bayer), a combination product (alpha-cypermethrin (IRAC = 3A) + dinotefuran (IRAC = 4A), Alucion®, BASF) and an insect growth regulator (novaluron (IRAC = 15), Suprado™, QualiPro). On the other side of the turfgrass insecticide ledger, it is likely that older chemistries will be phased out of the market as federal agencies conduct periodic reviews of registrations. In February 2022, the Environmental Protection Agency (EPA) announced that it would be banning agricultural uses of the organophosphate chlorpyrifos (IRAC = 1B), leaving many to wonder about its continued use in turfgrass. A total ban of chlorpyrifos has already occurred in New York and Maryland, which has caused some confusion as to its use in other states. I admit that I was confused and did not fully understand the changes at the federal and state level, and therefore set out on a mission to better educate myself. This article is not an endorsement of chlorpyrifos, but rather a means to help inform readers of what to expect in the short-term regarding its use in turfgrass.
Organophosphates
The insecticidal properties of organophosphates have been known since the mid-1800s with the first compound (tetraethylpyrophosphate) being synthesized in 1854. Organophosphates work by inhibiting an enzyme (acetyl choline esterase) in nerve cells. Acetyl choline esterase degrades the chemical neurotransmitter that causes a nerve impulse that would otherwise turn the impulse into muscle movement. The delivery of an organophosphate into the insect’s body essentially stops the enzyme’s normal functioning, the neuron fires repeatedly, which leads to muscle overuse and tetany, and eventual death. Human nerve cells also possess acetyl choline esterase and therefore can suffer adverse acute and/or chronic reactions when exposed to organophosphates. It is also for this reason that many organophosphates active ingredients were discovered. Organophosphates were used as insecticides in the 1930s, though thousands of compounds were developed in Nazi laboratories during this period to discover nerve toxins that could be used on the battlefield. Organophosphates that demonstrated promise in insect control were made available to the public for agricultural and residential use after World War II.
Organophosphates in turf management
Several organophosphates have been used to control turfgrass insect pests over the last 70 years though only three active ingredients (acephate, trichlorfon, chlorpyrifos) are commonly used today. General characteristics of organophosphates include contact activity, limited mobility (as they bind to organic matter), and relatively low residual activity or half-life within the soil. Subtle differences can be observed between organophosphate active ingredients, leading to slight changes in their use. For example, the biggest difference between all three organophosphates used in turfgrass is that trichlorfon (e.g. Dylox ®, Bayer) has much, much greater solubility than acephate and chlorpyrifos which are relatively insoluble. Trichlorfon solubility allows it to move through the soil profile despite having high binding potential like the other organophosphates. Therefore, it can be used as a curative white grub larvicide, whereas the other two actives are relatively insoluble and likely to bind to thatch and organic matter before reaching the target site. Therefore, the primary use for most organophosphates in turfgrass insect management is limited to contact control of surface-active insects.
Regulatory review
Chlorpyrifos, which became a mainstay for agricultural and household use after its discovery in 1965 due to its persistence and relative safety compared to others within the class, has been reviewed by the EPA multiple times. The EPA reviews the registration of any pesticide every 15 years and considers new scientific findings in the continued registration of the active ingredient. The EPA mandate is to only register a pesticide “when it determines that it will not cause unreasonable adverse effects on humans or the environment, while considering the economic, social, and environmental costs and benefits of the use of the pesticide (Federal Insecticide, Fungicide, and Rodenticide Act).” Several organophopshates developed around the same time as chlorpyrifos have been banned by the EPA for their potential adverse effects on human health, though the phase-out process can be lengthy. The phase out of diazinion began in 1988 after a link between its use and massive bird die-offs in open spaces (including golf courses) was established. However, the last sale of diazinon was not until in 2004. Phasing-out of certain uses of chlorpyrifos has also been a lengthy process. Changes to the Food Quality Protection Act (FQPA) in 1996 set a more rigorous safety standard to reduce children’s exposures to pesticides, which in turn led to the voluntary elimination, phase-out, or modification of certain uses of chlorpyrifos in 2000. Other reviews have occurred in the last 22 years, including changes to labels to protect workers (2002, 2012) and periodic human health risk assessments as new information becomes available (2011, 2014, 2016, 2020).
Sifting through the EPA documents pertaining to the EPA registration reviews can be dull, but five years ago things started to get interesting. In 2017, environmental advocacy groups brought forth a petition to revoke all chlorpyrifos tolerances and cancel all chlorpyrifos registrations based on the 2014 human health assessments. It has long been known that chlorpyrifos exposure can be more harmful during development than in adulthood and that these impacts to the developing brain can contribute to behavioral abnormalities. Despite this, the petition was denied based on the need for more time to examine the science addressing neurodevelopmental effects. This ruling was challenged in the U.S. Court of Appeals for the Ninth Circuit, which hears cases pertaining to civil and criminal matters that fall under federal law. In 2021, the Court found that the EPA’s denial was arbitrary and issued a final rule revoking the tolerances unless the EPA could show the tolerances were safe….otherwise, they would need to modify or cancel food-use registrations for chlorpyrifos. In February 2022, EPA issued letters to companies with chlorpyrifos registrations indicating that they will proceed with canceling the registered food uses.
It is important to note that these rulings have implications for food-use registrations as many non-agricultural/non-food uses of chlorpyrifos remain registered. I think much of the assumed deregistration of chlorpyrifos in Pennsylvania turfgrass has come from the media attention given to the cancellation of uses pertaining to agricultural uses without emphasizing allowance for certain systems. Some confusion may arise from the fact that our neighbors in New York and Maryland have total bans on
chlorpyrifos as well, which may have led to regional distributors discontinuing sales within turfgrass. Even with chlorpyrifos registrations in place in Pennsylvania turfgrass, this does not pertain to all turfgrass sites. According to the Pennsylvania Department of Agriculture, chlorpyrifos has been prohibited for residential turf sites within the Commonwealth. The Department has not taken any further action to restrict use of chlorpyrifos on golf courses, sod, and industrial or highway turf areas.
What next?
I wrote this article because I had assumed that chlorpyrifos bans in turfgrass were imminent and that Pennsylvania, much like neighboring states, had begun phasing-out chlorpyrifos. I had mentally moved on to a life without the active ingredient. For some (maybe most) this is not too hard to imagine. The good news is that better (i.e. more efficacious, more selective/less broadly toxic) alternatives to chlorpyrifos exist for almost every turf insect situation. The major exception to this rule happens to be one of the greatest challenges in turfgrass insect management. The management of pyrethroid-resistant adult annual bluegrass weevils (ABW) is hindered by a limited number of effective options. In this case, a single, well-timed application of chlorpyrifos against emerged, overwintering adults in spring is currently recommended to reduce some of the egg layers and synchronize larval development. Secondly, I am quite optimistic that solutions will be developed (and registered) for this issue in the very near future.
It is not difficult to recognize that there are inherent issues with many early generation insecticides like organophosphates and the adverse neurodevelopmental effects to agricultural workers exposed to chlorpyrifos and their offspring should cause pause. The EPA will continue to review chlorpyrifos registrations in the future and it is likely that the situation in Pennsylvania could change quickly. So, though this article may be helpful to some for-product selection in the short-term, I think it wise to plan for alternative approaches in the future whether mandated or not. The Turfgrass Entomology Laboratory is committed to working on this issue and it is my hope to be reporting on our adult ABW control research in the near future.
For more information and documents related to the review process:
THE PENNSYLVANIA RESPONSIBLE FERTILIZER USE BILL IS LAW!
By Max Schlossberg
L
egislation mandating responsible use of fertilizer per updated application standards was recently signed into Pennsylvania law as Act 83 of 2022. The statute enacts several critical mandates to modernize the state’s existing fertilizer testing and labeling programs and establish clear rules governing fertilizer application to turfgrass, without introducing bureaucratic hurdles to our industry. Components of previouslyproposed bills that do not appear in Act 83 include the fertilizer applicator certification program and comprehensive fertilizer application record keeping requirements. Act 83 directs the Pennsylvania Department of Agriculture (PDA) to establish a new agricultural and homeowner education program to inform the public about best practices for the application of fertilizer.
Fertilizer Licensing & Registration
The first section of Act 83 refines regulations pertaining to fertilizer manufacturers and distributors in PA. One of the component requirements is turfgrass fertilizers must exclude phosphate (P2O5) and contain ≥20% enhanced efficiency nitrogen (N), unless the product is a starter, natural organic (derived from either plant or animal products and containing at least one mineral nutrient), or organic-based fertilizer (>50% of guaranteed primary nutrients derived from organic materials). Exceptions to this requirement are readily-available liquid, or granular, fertilizers.
Fertilizer Application and Prohibited Acts
Act 83 specifies restricted locations and dates of fertilizer application. Regarding location, fertilizer cannot be applied within 15 feet (4.6 meters) of the top of a bank of a lake, pond, wetland(s) or flowing body of water, such as a stream, river or creek; except when using a drop spreader, rotary spreader with a deflector, or targeted spray liquid. Application of fertilizer containing N and/
or P2O5 is prohibited for the purpose of melting ice (official airport use exempted) and when the ground is snow-covered or frozen to a depth ≥2 inches. Total N fertilizer applied between December 15 and March 1 is limited to 0.5 lbs N per 1000 sq. ft. Responsible methods of fertilizer application and storage are further mandated by Act 83. For example, it states no one shall apply fertilizer in a faulty, careless, or negligent manner; or with a device neither properly calibrated nor intended for the application of fertilizer. These are important and meaningful goals! I have already volunteered to assist PDA’s development of a practical rotary spreader calibration method to help DIY enthusiasts avoid needless steps and equipment procurement in fulfillment of this simple objective. Furthermore, Act 83 states no one shall dispose of, discard, or store a fertilizer product in a manner inconsistent with its label. Fertilizer over-application, or negligence resulting in direct discharge to a storm drain or waters of this Commonwealth is henceforth prohibited by state law. Resultingly, fertilizer labelled for use on turfgrass that is inadvertently applied to an impervious surface shall be removed from the impervious surface immediately following application.
General Fertilizer Application Rates for Turfgrass
As with most turfgrass fertilizer statutes in the Mid-Atlantic region, Act 83 restricts turfgrass fertilizer applications to 0.7 lbs of readily available (soluble) N and 0.9 lbs of total N per 1,000 sq. ft. per application made between 2 March and 14 December. Application of enhanced-efficiency N fertilizer exceeding 0.9 lbs total N per 1000 sq. ft. is permissible as long as ‘the amount of N released at any given time does not exceed 0.7 lbs N per 1000 sq. ft.’ This relates back to the ≥20% enhanced efficiency nitrogen (N) fertilizer guidance. For example, a 0.9 lbs N per 1000 sq. ft. application using a fertilizer containing 23% water-insoluble N would release <0.7 lbs readily-available N (per 1000 sq. ft.) upon activation.
Fertilizer manufacturers specify the water-insoluble and/or controlled-release N fraction of the fertilizer in the guaranteed analysis section of the label, and these percentages are validated by the state chemist. Either insoluble or controlled-release nutrient fractions comprise an efficiency enhancement by extending the opportunity for plant nutrient uptake and reducing potential nutrient loss to the environment.
The most effective turfgrass managers apply fertilizer for the purpose of rectifying a nutrient deficiency and/or satisfying the plant nutrient(s) requirement for an appropriate length of the growing season. Given an ongoing nutrient requirement, that length of the growing season would constitute the re-application interval. However, not every nutrient is required over all growing stages. Moreover, since the underlying soil may already possess nutrient(s) at satisfactory concentration(s), soil testing is a useful tool for determining a required need; i.e. rate, of nutrient addition. That needed nutrient rate is provided by the soil test recommendation, and we use fertilizer to promptly supply the recommended rate of nutrient to the plant.
Per Act 83, readily available P2O5 fertilizer can only be used at the specific rate recommended by PSU in a <3 year-old soil test report of intent to establish or repair the specific turfgrass system. Otherwise, single application of P2O5-containing enhanced-efficiency or natural organic fertilizer to mature turfgrass is capped at 0.57 lbs P2O5 (0.25 lbs P) per 1,000 sq. ft. and 1.14 lbs P2O5 (0.5 lbs P) per 1,000 sq. ft. annually.
Provisions for Fertilizer Application Rates for Turfgrass
Act 83 affords exception to the above regulations given a sitespecific plan is used, and requires ALL of the following:
• A soil test was conducted within the previous 3 years in accordance with procedures recommended by Penn State Univ.
• Current soil, plant species, climate, use, topography or other appropriate management factors.
• Rates recommended by The Pennsylvania State Univ., or other institution of higher education in this Commonwealth, and approved by the PDA.
Likewise, the PDA may establish use and application rates for fertilizer(s) that is/are applied to turfgrass based on appropriately peer-reviewed scientific research representing conditions of this Commonwealth and recommended by The Pennsylvania State Univ. or other institution of higher education in this Commonwealth.
Summary
So while the described turfgrass fertilizer application rate, date, and location restrictions articulated in previous versions of the Fertilizer Responsible Use Bill were to be required of commercial operators, i.e., PDA-certified fertilizer applicators; they now apply to anyone fertilizing turfgrass in the Commonwealth. Meanwhile, none of the described restrictions pertain to: land used for an agricultural operation, lawful use of fertilizer in blasting (construction) per Dep. of Environmental Protection regulations, or use by a public or private institution of higher education for research purposes.
Compared to the other states within the Chesapeake Bay watershed, Pennsylvania possesses a host of unique nonpoint source challenges and opportunities in its sub/urban communities. Having entered the Final Phase 3 Watershed Implementation Plan, Act 83 comprises a successful Pennsylvania state government action supporting best management practices to reduce sub/ urban nonpoint N and P pollution loads in the Susquehanna and Potomac basins. Let’s all use less fertilizer more responsibly to maintain healthy turf AND achieve the water quality restoration goals needed in the Chesapeake Bay.
A PRACTICAL METHOD OF Rotary Spreader Calibration
By Max Schlossberg, Ph.D.
Accurate and uniform distribution is the essence of effective turfgrass fertilization, and broadcast application of granular fertilizer via spreader is the most common method used. Spreader calibration entails the measuring and establishment of fertilizer output from a spreader operating over a known area.
The first step in calibrating any spreader
Regardless of which book, article, website, or fact sheet you are reading, the first step of spreader calibration is determining the granular fertilizer or amendment application rate in lbs product per 1000 sq. ft. (M). For pesticides, lime, or amendments, this is typically best achieved by following label or soil test recommendations. For nutrient recommendations provided in a specific soil test report; e.g., a recommendation of 2 lbs K2O per M, the fertilizer grade will be required to scale the fertilizer application rate. This is achieved by inserting the recommended nutrient delivery rate into the numerator and inserting the decimal form of the percent nutrient contained in the fertilizer into the denominator (Figure 1).
It is crucial that the percent nutrient contained within the fertilizer, reported as a percentage by mass either in the fertilizer grade or guaranteed analysis, be included in its decimal form. In this example, the desired K-Mag fertilizer (0-0-22) application rate is 2 divided by 0.22, or 9.1 lbs K-Mag fertilizer (0-0-22) per M. Insert this value into the ‘Desired fert/amend application rate (lbs/M)’ slot of the rotary spreader calibration equation (Figure 2).
The second step of rotary spreader calibration
The next step in my rotary spreader calibration method is measuring the fertilizer specific treatment swath. It diverges from more commonly recommended approaches, but sensibly addresses a poignant question: Why does fertilizer application by a rotary spreader sometimes leave stripe artifacts (Figure 3)?
The answer(s) is one or both of the following:
1. Successive spreader passes, back and forth across the target area, were made too far apart.
2. When operated in the traditional back and forth manner, an asymmetric distribution of fertilizer from the spreader prevailed across the treatment swath; i.e., one side heavier than the other.
The opportunity for the first of these issues will certainly arise, while that for the second may or may not. The first reason stripe artifacts occur isn’t surprising given the only thing exceeding the number of approaches used to determine ‘the specific distance to maintain between passes’ is the number of ways to reference it.
Such crafty monikers include: treatment band/swath/width, distribution band/swath/width, effective spacing, and effective swath width, among others. Over the 25 years I’ve instructed turfgrass students on this topic, I’ve consistently used ‘distance to be maintained between pass centers (feet)’ in my rotary spreader calibration equation (Figure 2). Perhaps this intuitive, straightforward terminology is what deters widescale adoption, but I can dare to dream and will continue using it.
The second step of my rotary spreader calibration method has practitioners assess the right-to-left symmetry of the treatment distribution as well as its swath in feet. Thus, successful completion should resolve both the above-mentioned causes of striping artifacts. The outcome of the asymmetry test determines whether a 100% or 200% overlap should be employed during the ultimate granular product application but does not influence determination of the distance to maintain between passes (feet).
FIGURE 2
FIGURE 1
FIGURE 3
Measuring the treatment swath is a critical step of rotary spreader calibration as explained by Mr. Lance Walheim of the National Gardening Association:
‘To use a broadcast spreader properly, you need to know how wide a band the spreader covers. If the directions that came with the spreader don’t indicate the width, put some fertilizer in the spreader and run the spreader over a short stretch of lawn to find out.’
Word, Mr. Walheim! Determining the treatment swath in feet is by no means a ‘separate’ or ‘optional’ step in the procedure. The treatment swath (feet) will vary by product, and in some cases by walking speed too, but is required for every unique combination of rotary spreader model and granular product to be applied. Mr. Walheim further states; ‘don’t measure the coverage on concrete unless you plan to sweep up the fertilizer.’
His middle name is ‘Butta’ because he’s on a roll! When the ultimate destination of the product is maintained turfgrass, this should be measured on maintained turfgrass. Measuring the treatment swath on smooth pavement increases spreader travel rate, boosts speed of the impellor disc rotation, and exaggerates the treatment swath; further contributing to stripe artifact by way of Issue #1. It will also extend the time needed to complete the spreader calibration task due to sweeping requirements.
Excepting the clean, dry rotary spreader and granular product to be applied, Figure 4 comprehensively depicts all the equipment required to calibrate a rotary spreader. No future surprises, it’s all there in full! Step 2 requires each of the two clean rectangular tarps be spread approximately 15 inches apart on an eligible, representative turfgrass system. Next, examine the rotary spreader and ensure the metal screen is set in position (Figure 5). Open the hopper gate and examine the gate openings on the hopper bottom. They should be approximately one-third open ( Figure 6 ). If not, shut the hopper gate and follow the spreader instructions to adjust the hopper gate openings to an approximately one-third open position.
FIGURE 5
FIGURE 6
FIGURE 4
Close the hopper gate, tighten the adjustment knob (for good measure), and carefully fill the hopper with 10 lbs of the desired granular product.
Next, the intended applicator positions the spreader 20 feet away from the tarps (Figure 7) and begins walking at a safe yet briskly consistent pace toward the gap between the tarps.
FIGURE 7
Rochester,NY
Excalibur™
CompetingSurfactant
Firmness(TrueFirm)
Once up to speed, and no less than 15 feet from the leading edge of both tarps, the applicator should firmly swing open the hopper gate lever while directing the spreader straight through the gap between the tarps (Figure 8). Once aligned with the trailing edge of the tarps, the applicator can close the hopper gate lever. This process should be repeated, always travelling in the original direction, until a measurable quantity of granules is visible on both tarps.
At this time, a measuring tape is used to determine the treatment swath in feet. The outer edge of granules on the tarp should not be
considered the boundary of the treatment swath. Rather, it should be used as a guide to locate the outer edge of granules in the turfgrass (along the leading edge of each tarp). The boundary of granules in the turfgrass is what should be used for measurement. If the granules bounced across the tarp, then the outer edge of granules in the turfgrass will rest closer to the gap than the outer edge of granules on the tarp. Place a pin flag to denote the boundary, then repeat using the leading edge of the granules on the other tarp as a guide to locate the outer edge of granules in the turfgrass.
FIGURE 8
Once set, measure the distance between the two pin flags in feet (Figure 9), and record as the treatment swath. Then retrieve the pin flags and measuring tape. To complete Step 2, divide the treatment swath by two. For example, the treatment swath depicted in Figure 9 is 18 feet. One half the treatment swath is the distance to be maintained between pass centers, or 9 feet in this example. Yes, meeting a 100% overlap goal is just that easy (Figure 10).
Ubiquitous alternatives to the above method are inextricably elaborate, yet poorly supported by experimentally-derived fertilizer distribution from commercial, walk-behind rotary spreaders. Given a treatment swath measuring 18 feet, enter the value of 9 feet into the ‘Distance to be maintained between passes (feet)’ slot of the rotary spreader calibration equation (Figure 11).
Many refer to this method as ‘spreading wheel-to-wheel’ and consider their view of it to be much simpler than mine. Sure, spreading wheel-to-wheel is a simplistic way of saying your next pass center will be made at the edge of where your last pass distributed fertilizer. Conceptually, the wheel-to-wheel directive would indeed amount to a 9-foot distance maintained between pass centers for the Figure 10 example. However, as simple as a directive that may be to one employee, it may prove operationally problematic for another.
FIGURE 10
FIGURE 9
FIGURE 11
As an assistant superintendent who trained teammates to calibrate a rotary spreader for their use, I felt comfortable identifying the finite distance to maintain between subsequent passes. Effective communicators give directions that are not open to interpretation. Likewise, when critical precision is ultimately required of the planned granular treatment, practitioners can use measuring tape and alternatingcolored pin flags to ensure that 9-foot distance is in fact maintained between passes (Figure 12). Without belaboring it further, trust me when I say I’ve collected a lot of data, acquired even more, and run a hundred simulations. All other inanely-complex distribution sampling, plotting, and midpoint calculating steps will not prove more reliable a method as maintaining half the total treatment swath between passes, period. The more diligent the operator is about determining and maintaining this half the treatment swath distance between passes, the more successful the outcome.
Now that you are convinced of that, grab one of the two clean buckets and carefully lift the corners of one tarp to collect all the granules along the middle of one edge. Position the bucket accordingly and transfer all granules into it, then set that granuleladen bucket safely aside on a stable surface. Repeat the process on the second tarp using the second clean bucket. If the mass of granules in each bucket resides within the operating range of your balance, then carefully determine each mass and record. Alternatively, the volume of granules collected from each tarp
can be measured by transferring the granules into a graduated cylinder. Gently tap the filled cylinder to facilitate consistent settling and a uniform bulk density, then carefully determine each volume and record. This information will be used momentarily.
The next step is to mark out a practice run length on representative turfgrass. The length of the practice run should be no less than 25 ft but need not exceed 60 ft. I’ve noticed some industry YouTube videos encourage their subjects to determine the practice run length by dividing 1000 sq. ft. by the number of feet the spreader treatment swath is wide. These folks then go on to present a simplified equation, where the practice run target mass equals the desired fertilizer/amendment rate in lbs per M. Yet the spreader treatment swath width is never again mentioned.
So, allow me to briefly support my characterization of this recommendation as highly-suspect, or ‘sus’ as PSU students sometimes say. First, accurate balances and proportional properties of multiplication facilitate precise calibration at reduced scale, i.e., we don’t have to treat 1000 sq. ft. (M) in each practice run to calibrate our rotary spreader to lbs per M.
Second, using a practice run length equal to 1000 divided by the treatment swath width, for the purpose of setting the practice run target mass equal to the desired fertilizer/ amendment rate, presumes the treatment swath width distance will be maintained as the distance between pass centers.
And while a 0% overlap approach proves adequate when operating a drop spreader, expectations of further versatility are misguided. While all turfgrass scientists may not agree whether rotary spreaders apply granules in a semi-circular, triangular, or trapezoidal distribution across the swath width, I’m pretty certain none are betting the perfectly-rectangular horse.
Getting back on topic, next use paint or pin flags to mark at least one 25- to 60-foot practice run over representative turfgrass. Employ of a calibration kit (Figure 13) facilitates reuse of a single practice run as many times as necessary. If a calibration kit is not available, multiple practice run lengths will be required and any number will be treated by the product at a rate less or greater than the desired application rate. Frankly, it depends on how close your first hopper gate setting guess comes to delivering the target mass.
You will employ pin flags to avoid double treating practice run lengths. If calibrating your rotary spreader to apply a desired rate of pesticide, then you could really use a calibration kit! Otherwise, the area receiving product from iterative practice runs must be accurately described in pesticide application records; and treated areas may not be re-treated in a manner prohibited by the label.
Again, one can never be certain how many practice runs will be required, but the number typically exceeds one.
The third step of rotary spreader calibration
Before I get too far ahead of myself, let’s suppose several practice runs 25 feet in length will be marked in the representative turfgrass area. Insert this value into the ‘Length of practice run (feet)’ slot of the rotary spreader calibration equation and solve for ‘Target lbs fertilizer applied in practice run.’ The resulting target fertilizer mass to be applied over a 25-foot practice run is 2.05 lbs K-Mag ( Figure 11 ). We have now completed over half the rotary spreader calibration steps. A remaining task is committing to either 100 or 200% overlap. Committing to 200% overlap is the more admirable option but requires twice as many traversing passes when making the planned granular treatment. The information I use in the decision rule, and encourage the readers to use as well, is the right-to-left distribution of granules as determined by the tarp collections.
FIGURE 13
If the masses or volumes of granules collected from the adjacent tarps were identical (or nearly), then a 100% overlap will suffice in preventing stripe artifacts. This means the calculated ‘practice run target mass= 2.05 lbs K-Mag fertilizer)’ should be employed in the final step (#4).
If the masses or volumes of granules collected from the adjacent tarps were dissimilar; then you may have options for resolving this issue. If your rotary spreader has a distribution adjustment cone between the hopper and impellor disc, then you can consult the spreader manual and follow the instructions they provide for centering the distribution swath. That’s your Option #2. Using two tarps, this will prove a time-consuming and iterative process without assurance of rewarding outcome. Using eight to sixteen ‘cake pans’ or ‘egg cartons’ spread across pavement to iteratively center the treatment swath defers a notable sweeping commitment, and is without question the most ludicrously impractical suggestion I have typed this year. If you agree, or your rotary spreader does not feature a distribution adjustment cone, then consider Option #1: Calculate the ‘asymmetry ratio’ by dividing the bigger tarp collection value by the smaller. When employing 100% overlap, the extent to which this asymmetry ratio exceeds 4/3 (1.33) correlates directly to the likelihood of striping by way of Issue #2. Thus, to prevent stripe artifacts, practitioners are suggested to employ a 200% overlap when the asymmetry ratio exceeds 1.33. This means the ‘as calculated’ practice run target mass is then further divided by 2, which makes sense given twice as many passes will ultimately be made across the treatment area.
In our example, 247 mL of fertilizer was collected from one tarp and 185 mL collected from the other (Figure 14); resulting in an asymmetry ratio of 247/185= 1.34. Thus a 200% overlap should be employed, making 2.05∕2= 1.025 lbs K-Mag the ‘practice run target mass (lbs fertilizer)’ goal of the final step.
FIGURE 14
The final step of rotary spreader calibration
Now it is time to iteratively confirm the hopper gate setting satisfies the desired application rate. There are three general ways to do this, selection of the most ideal method will depend on your specific rotary spreader and available ancillary equipment.
I. Volume replacement procedure (good for large, mounted, or tractor-drawn spreaders)
STEP 1. Set the spreader on a (suspected) desirable setting, making sure spreader is off (closed).
STEP 2. Fill the spreader hopper full, or to a clearly marked and repeatable level, with your fertilizer.
STEP 3. With the spreader, begin walking at a typical and constant rate and open the hopper gate at the marked/ flagged starting point, continue over the practice run length, and close the spreader at the appropriate end point.
STEP 4. Return the spreader to the scale vicinity.
STEP 5. Tare a bucket, fill it with the fertilizer material, and weigh and record the material mass.
STEP 6. Use the fertilizer in the bucket to refill the spreader hopper to the original level (Step 2).
STEP 7. Weigh the fertilizer remaining in the bucket.
STEP 8. By subtraction, determine the mass of fertilizer spread while walking. This is fertilizer mass applied per linear distance (at previously walked speed, NOT ANY speed).
STEP 9. Determine if more or less than the target mass was applied, adjust the hopper gate setting accordingly, and repeat.
II. Indirect mass (or remainder) procedure (good for small spreaders that can easily be emptied)
STEP 1. Set the spreader on a (suspected) desirable setting, making sure spreader is off (closed).
STEP 1. Tare a bucket and fill it with the fertilizer material, then weigh & record the material mass.
STEP 3. Carefully, transfer all the fertilizer to the spreader hopper.
STEP 4. Begin walking at a typical and constant rate with the spreader, open the hopper gate at the marked/ flagged starting point, continue over the practice run length, and close the spreader at the appropriate end point.
STEP 5. Carefully transfer the fertilizer remaining inside the spreader hopper to the original tared bucket.
STEP 6. Weigh the fertilizer in the bucket and record its mass.
STEP 7. The difference in fertilizer mass, from before walking the practice run to after, is the fertilizer mass applied per linear distance (at previously walked speed, NOT ANY speed).
STEP 8. Determine if more or less than the target mass was applied, adjust the hopper gate setting accordingly, and repeat.
III. Direct mass measurement (best, but REQUIRES a PENN PRO calibration kit)
STEP 1. Set the spreader on a (suspected) desirable setting, making sure spreader is off (closed).
STEP 2. Install the enclosure kit PROPERLY (covering the spinning rotor plate/impellor disc).
STEP 3. Remove and empty collection pan, place pan on balance, tare to zero, return pan to kit enclosure.
STEP 4. Fill the spreader with an ample quantity of your fertilizer.
STEP 5. Begin walking at a typical and constant rate with the spreader, open the hopper gate at the marked/ flagged starting point, continue over the practice run length, and close the spreader at the appropriate end point.
STEP 6. Carefully collect all the material into the detachable collection pan, ensuring all prills have been collected from the calibration kit enclosure! Failure to recover all fertilizer from the kit will result in improper calibration.
STEP 7. Detach collection pan and weigh. This is the fertilizer mass applied per linear distance (at previously walked speed, NOT ANY speed).
STEP 8. Determine if more or less than the target mass was applied, adjust the hopper gate setting accordingly, and repeat.
Review: When is using a 200% overlap (spreading at ½ rate in two perpendicular directions) appropriate?
1. When the rotary spreader distribution is skew, or heavier on one side than the other; i.e., the asymmetry ratio exceeds 1.33.
2. When applying seed (or a seed/amendment blend) to a bed prepared for turfgrass establishment.
3. When spreading fert./amend. on a windy day.
4. When the desired application rate (lbs fert./amend. per M) exceeds the maximum rate of delivery by the spreader. For instance, when you seek to apply 35 lbs pelletized limestone / M but can only apply 19 lbs pelletized limestone / M with the hopper gate wide-open (and at your typical walking speed). In this event, do not slow down your walking speed to achieve a 35 lbs pelletized limestone / M rate! Instead, maintain your original walking speed (and treatment swath) and calibrate the spreader to apply ½ the original rate (1/2 of 35), or 17.5 lbs pelletized limestone / M. Apply the 35 lbs pelletized limestone / M by making two perpendicular passes over your target area.
Covers That Make the Difference
Turf Institute Targets High School Ag Teachers and Their Students
Turfgrass science offers careers in “an industry that includes recreation, stewardship, and art,” says Penn State Agricultural and Extension Education Science PhD student Carson Letot. However, he is concerned about the labor shortage in the turf industry. Declining numbers in turf programs at the post-secondary level are leading to staffing gaps across the industry, but intervention at the secondary level to create interest and awareness may help. Youth competitions, content delivery, and experiential learning opportunities have all been shown to attract high school students. Previous experience on golf courses or playing sports on turf fields may also influence students to consider a career in turf. But with so many different requirements in levels of education and training in skillsets ranging from agronomy to leadership, the challenge of filling jobs remains enormous. One approach is to work through key figures like coaches, athletic directors, and science educators at the secondary level to expose students to the industry.
Turf Science for High School
KAFMO has been at the forefront of developing strategies to raise awareness of turf careers in high school. This past May, it sponsored its first weekend-long Turf Institute at Penn State University to introduce high school ag teachers to turfgrass science. According to Kristen Althouse, Education Manager for the Sports Field Management Association and one of the organizers of the Turf Institute, “Agriculture teachers are highly influential when it comes to introducing high school students to career options. Jobs in the turfgrass science industry offer exciting opportunities for young people who enjoy working outdoors and doing something different every day, take pride in their work, and have a passion for sports. Currently, job opportunities are abundant with job availability exceeding demand either as a summer job or long-term career.” The hope is that teachers will add the study of turfgrass to their curriculum and raise awareness of turfgrass science among students at the secondary level.
Carson Letot gives us an overview of the weekend institute. Ten teachers from Pennsylvania and Virginia met on the campus of The Pennsylvania State University for the 2022 Turf Institute, a program to engage educators in two days of professional development centered on golf and sports turf.
Participants visited Mountain View Country Club, Beaver Stadium, Medlar Field, and Valentine Turfgrass Research Center. At each site they had an opportunity to work with the field manager paired with a Penn State turf science faculty member. Teachers learned about the skills and training needed to begin a career in turf management, as well as the science behind how the turf is maintained. They left the institute with tools and practical knowledge to bring the science and art of turf management back to their classrooms and expose students to a discipline that can take advantage of the fields around their schools as learning spaces and the turf managers in their communities as facilitators for experiential learning opportunities.
Researching Teacher Efficacy
The weekend was not just a hands-on opportunity for educators to add to their own knowledge of turf science, however. It also served as a pilot study to investigate teacher efficacy in turf science teaching and explore opportunities for future activities, according to Letot. The objectives for the study were to (a) Identify the level of familiarity educators have with turfgrass content; (b) Identify the level of competence educators have in delivering content in turfgrass science; (c) Describe the best practices teachers have for establishing connections with turf managers to facilitate experiential learning opportunities. This pilot study was initiated in a partnership between the Center for Professional Personnel Development (CPPD) and the Center for Turfgrass Science at Penn State. Three main research questions in the areas of curriculum, instruction, and outreach emerged:
• How do we improve the content knowledge of educators through curriculum offerings?
• How do we approach training for educators through teaching interventions in a workshop centered on turf-related skill building?
• How do we improve teacher efficacy in outreach through the establishment of connections with local industry to provide opportunities for students?
Letot described his methodology in assessing teacher progress in these areas. The ten participants were pre- and post-assessed on their knowledge of curriculum, instruction, and outreach. Results showed significant growth in overall confidence in teaching turfgrass science as well as facilitating opportunities for their students to work with local turf professionals through outreach. Baseline assessments in outlets for turf science in existing courses showed that educators are willing to connect concepts in turfgrass science to topics in existing courses at the secondary level. In addition to course connections, participants showed improvements in confidence to teach turfgrass science. This confirms that even shortterm professional development opportunities can lead to improvement of knowledge, self-confidence, and understanding.
Contact: Linda Kulp, Executive Secretary Phone: 717-497-4154 kulp1451@gmail.com
Contact: Dan Douglas, President Phone: 610-375-8469 x 212 KAFMO@aol.com
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Reaching the Next Generation
Finally, participating teachers revealed that their view of the turf industry had improved. They are now willing to reach out to local professionals and bring turf experiences to the students and may also now be more likely to be advocates for employment in the turf industry. When students experience success and encouragement in subject areas, they develop positive attitudes towards those subject areas and studies have shown improvements in the career prospects of STEM majors when support was provided. Support in the turfgrass industry is plentiful and the results could have a positive impact on the future labor market.
Carson Letot hopes that future research will explore student response to turfgrass science and career opportunities. The role of high school science educators on influencing students to choose a career in turf or a turf major at a post-secondary institution has not yet been measured, he says. He believes that measuring the effectiveness of training in the form of professional development for high school educators will not only reveal opportunities for recruitment but also provide feedback so that KAFMO and SFMA can improve the programs offered to high school teachers and ultimately reach greater numbers of the next generation of young turf science recruits.
IN MEMORIAM
Wakar Uddin
Wakar Uddin, PhD, Professor of Plant Pathology and Turfgrass Disease Specialist in Penn State’s College of Agricultural Sciences, passed away peacefully on April 29, 2022.
A Rohingya American born in Maungdaw, Arakan State, Burma (Myanmar) in 1954, Wakar immigrated to the U.S. where he received bachelor’s and master’s degrees in integrated pest management at the University of Nevada. He received his doctorate in plant pathology from the University of Georgia in 1996, then supervised the Georgia Plant Disease Clinic before joining Penn State in 1998 as the Turfgrass Pathologist.
Dr. Uddin taught plant pathology courses to hundreds of undergraduates and World Campus students and conducted educational seminars for the industry. His research focused on epidemiology and management of gray leaf spot of perennial ryegrass turf, induced resistance in turfgrass systems through integration of plant defense activators, and integrated management of turfgrass diseases. His findings led to new disease control products and practical guidance on disease management appreciated by golf course and sports turf managers worldwide. He is remembered as a great communicator who was well respected and esteemed by his students and colleagues.
In addition to his work in plant pathology, Dr. Uddin served as director general of the Arakan Rohingya Union, a federation of 61 Rohingya organizations worldwide recognized by the international community as the official voice of the Rohingya people. He was also the founding chairman of The Burmese Rohingya Association of North America and the president and chairman of the board of Trustees of Muslim Aid America.
Turfgrass
recovery of fertilizer N from
single
application of 100% polymer-coated urea (PCU)
Relative to soluble N sources, controlled release fertilizers (CRF) foster consistent turfgrass growth and improved canopy quality while reducing N loss from target systems. Commercial CRFs like polymer-coated urea (PCU) afford conscientious turfgrass managers greater operational efficiency and flexibility in nutrient management planning. Resultingly, polymer-coated urea (PCU) application rate thresholds are investigated annually within the PSU Valentine Turfgrass Research Center. This turfgrass nutrition research supports development of Pennsylvania Dep. of Agriculture regulations and fertilizer applicator guidance as mandated by the recently approved Responsible Fertilizer Use Act.
With technical assistance from George Fitch, pictured alum (TURF ’16), three field experiments were conducted to evaluate temporal response of Kentucky bluegrass yield, canopy density, color, and fertilizer N offtake to one practical application of granular fertilizer. Each mid-May, plots were fertilized by conventional urea or Duration 45 PCU at a N rate of 0.9 lbs N/1000 ft2; or Duration 90, Duration 120, or Polyon (43-0-0) PCU at a N rate of 1.8 lbs N/1000 ft2. Response proved similar over the 18-week experimental periods and was highly dependent on N rate and PCU attribute. Significant main effect showed mean clipping recovery of fertilizer N from conventional urea, Duration 45, Duration 90, Duration 120, or Polyon (43-0-0) totaled 63, 87, 82, 78, or 77%, respectively.
Varied N release curves among the PCU fertilizers indicate wide suitability by species and/or seasonal nutrient requirement(s). Greater detail is available in a 2022 open access publication; doi.10.3390/horticulturae8030207. Meanwhile, hypothesis tests on unaccounted, experiment-end fertilizer N totals show a single 1.8 lbs N/1000 ft2 application of 100% PCU fertilizers under conditions described poses no greater environmental risk than a 0.9 lbs N/1000 ft2 application made using conventional urea fertilizer.
Dates! These Save
NOVEMBER 15 – 17, 2022 PSU Golf Turf Conference
Penn State HUB Student Union
JANUARY 26, 2023
Northeastern PA Golf, Lawn, Landscape and Sports Turf Conference
The Woodlands Inn and Resort Wilkes-Barre, PA
FEBRUARY 2, 2023
Eastern PA Golf, Lawn, Landscape and Sports Turf Conference
Shady Maple Conference Center East Earl, PA
For use on: Trees, landscape plants, golf course tees, greens, fairways, and sports turf.
