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Surface Hardness Response to Localized Decompaction

Clegg impact tester

Clegg impact tester

Summary of new research by Christopher Sitko, Joshua Fontaine, Carl Schimenti, Frank Rossi documents how you can keep playing fields safe by reducing surface hardness:

Data-Driven Natural Grass Athletic Field Management: Surface Hardness Response to Localized Decompaction

High-performance athletic surfaces can benefit from a data-driven approach to management that increases field safety and performance by adding precision. Data-driven management of natural grass athletic fields adheres to playing surface quality and safety performance guidelines established by the Australian Sports Turf Institute for cool-season natural grass athletic fields. High quality athletic fields should inherently be safe for play. Surface hardness is a primary measure of field quality and safety and should be maintained to provide desirable ball-surface interaction and limit risk of head injury. Surface hardness is measured using the standard three-drop method with a Clegg Impact Tester. A weighted missile is released from a uniform height and measures the change in acceleration at surface impact.

The Cornell University Turfgrass Program has worked closely with Cornell Athletics to train students interested in working in the the sports turf industry. A recent student project monitored surface hardness weekly during the 2018 Spring/Summer playing seasons. Measurements indicated a localized area of surface hardness where readings exceeded head-injury threshold levels. Therefore, a localized decompaction system was implemented using a Toro 648 Procore fitted with ¾’’ solid tines followed by topdressing sand that filled open channels using a Dakota 310 Turf Tender. High quality topdressing material is important and should reflect the surface modification goals. This application used a clean, uniformly graded sand consisting of particles in the medium and coarse size fractions. The uniformity coefficient (Cu) of the topdressing sand tested at 2.5. The lower the Cu, the more uniform the particle size and the greater the compaction resistance.

Toro 648 Procore fitted with ¾’’ solid tines used to alleviate compaction

Toro 648 Procore fitted with ¾’’ solid tines used to alleviate compaction

Applying sand topdressing with Dakota 310 Turf Tender.

Applying sand topdressing with Dakota 310 Turf Tender.

Measurements were taken before, during and after the decompaction process. Before decompaction, 10 of 12 measurements collected from localized areas totaling 7500 sq ft had surface hardness readings above head-injury thresholds of 120 gravities.


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Following decompaction all 12 measurements were reduced on average by 30 percent and fell within the preferred range for safe play. Furthermore, the standard deviation (differences among initial measures) dropped by 40%, indicating a more consistent playing surface following decompaction.

This project demonstrates how high-performance athletic surfaces can benefit from a data-driven approach to management that increases field safety and performance by adding precision.

This work was conducted by our 2018 Sports Turf Research Intern, Rhys Moeller (former Varsity Soccer player for Cornell University), Josh Fontaine Sports Turf Field Research Manager, Chris Sitko Sports Turf Graduate Research Assistant, Carl Schimenti Cornell Turfgrass Program Manager and Frank Rossi, Cornell Turfgrass Program Leader.

Cornell University ShortCUTT Newsletter (Week 5 – May 14, 2018)

ShortCUTT Newsletter (Week 5 – May 14, 2018)

This week, Dr. Rossi discusses data-driven management and clarifies the concept of “Enhanced Efficiency Fertilizers.”

If you have any questions you would like us to address in future editions of the newsletter, please  contact Carl Schimenti at

New resource: Environmental Impact Quotient (EIQ) Explained

The Environmental Impact Quotient (EIQ)  helps you determine the environmental impact of most commonly used pesticides (insecticides, fungicides, and herbicides) in agriculture and horticulture. You can use the calculations you make to compare the environmental impact of different pesticides and pest management programs.

We just added a new resource to this site that explains how, including a links to the NYSIPM Program’s EIQ Calculator and video of an in-depth webinar introducing EIQ.

New! ‘Clippings’ podcast

We’re pleased to announce the launch of the Cornell Turfgrass Clippings Podcast.

The new podcast offers practical suggestions and cutting-edge tips from Cornell University Turf Guy Dr. Frank Rossi for professionals in the lawn, golf and sports turf industry in New York State and surrounding areas.

Initial topics include:

For more information, see our podcast page.

Subscribe (free):

What we can learn from the worlds best sports teams

Think of all of the excellent sports teams out there in 2016. The Golden State Warriors, the Chicago Cubs, the New England Patriots. What do they have in common?

Of course, they have great players and coaches, a pre-requisite to greatness. However, you will also find these teams were the first, and most eager to incorporate data and analytics into their organizational system.

For the past couple weeks, we have used our Twitter account to highlight many ways to collect data on Turf landscapes. Examples of the many aspects of turf management we covered were irrigation, soil nutrients, turfgrass varieties. Our goal was to expose people to the world of data collection, and show them that the ability to quantify things is out there and readily available.

We understand that the transitional process in accepting and analyzing data is a tough one to make. We are not disillusioned into thinking that by this time next year, you will be optimizing your entire operation using second order derivations of economic opportunity cost formulas. No, we are simply hoping that beginning data collection in even the smallest way will give you the momentum you need to create a snowball effect.

We would suggest starting small. Perhaps you could begin your data collection voyage by keeping basic weather data from a local weather station, like daily maximum and minimum temperature, and precipitation. Or, you could keep records of your pesticide and fertilizer applications in a computer program like Excel. When you notice a disease outbreak, you have the ability to go back and check when the last time you applied Product X was, or what the weather conditions were like leading up to the outbreak. This feedback loop, made possible by data collection, allows you make adjustments for future management decisions.

Consulting the data will give you added confidence when making decisions. No longer will you rely on “gut feelings” or what your friend down the road told you they did. You will be able to make informed decisions specific to your turf landscape, supported by facts.

As an example, say you are a golf course superintendent looking to justify your management decisions to the membership or owner. Perhaps you got soil sample results that showed organic matter levels are higher than you would like. You could go to ownership and reference your soil samples, and research that shows that high organic matter leads to increased disease probability in order to convince them of the need to conduct aggressive cultural practices. They will be more inclined to accept the minor disruptions in play if data is incorporated into your line of reasoning for such practices.

For those who are already a part of the data revolution, there are many advanced technologies in existence that can potentially revolutionize your operation. A particular technology we are intrigued by is called FAIRWAYiQ. FAIRWAYiQ is a tracking system designed to track the movement of every person on a golf course using smart tags. Every golf cart, player, worker, and piece of equipment can be tracked using an antenna router mounted a few stories in the air. This tool would rapidly optimize golf course operations. The pro shop could identify specific holes on the course that lead to slow play, and report to the Superintendent who could then make modifications in playability to the hole if necessary. The Superintendent could use the tracking software to monitor the maintenance program, and optimize it for time or fuel savings. The system could even update employees on gaps in play to perform uninterrupted maintenance. FAIRWAYiQ is still in the testing stage, but for more information, visit the FAIRWAYiQ website.

Kirk Lacob is the Assistant GM of the Golden State Warriors. Recently, he said: “Sure, we could run our team without all of the available data. But why would we?”

We can ask that same question to turf managers. Why would you manage a turf landscape without all of the available data? The world of sports revolves around one of the most unpredictable things in the world: human behavior. If they can use numbers to express truths and probabilities in that arena, surely we can do it in turf? What Lacob is really saying here is that there is no argument for not having data.

For the advanced data enthusiast, we encourage you to keep searching for ways to improve. Be a pioneer for others to follow, and constantly search for ways to improve. For the novice data collector, we hope to have convinced you that the term “data” is not something to be scared of. It’s not long lines of computer codes, or complex equations with symbols you’ve never seen before. At it’s core, it’s turning the activities or observations you complete on a daily basis into numbers. It has never been easier to enter the dawn of data, and it’s hard to argue against it’s merits. If you do, remember, the data is on our side…

Variety Guidelines now available as .pdf.

Thinking about starting a new lawn or renovating an old one? Looking for the right grass for your sports fields, fairways or putting greens?  This publication will help you choose the grass species and varieties best adapted to your growing conditions and management.

Download full publication [806 MB .pdf]

Download individual chapters:

Also available on iTunes.

Golf Course Nutrient Use Survey

The Golf Course Superintendents Association of America‘s Environmental Institute for Golf (EiFG) has published a follow up to the 2006 Golf Course Nutrient Use Survey. There were national reductions in N, P and K use, due to primarily three factors: Facility closure (9%), acreage reduction and rate reduction accounted for the remaining 90% reduction.

Of particular interest are the changes in nutrient management decision-making as impacted by new research on soil test recommendations, new approaches to interpreting soil tests such as MLSN, and an overall view expressed that recommendations had lead to gratuitous applications. More information.

‘Best Practices’ newsletter – Week 1

New York State Best Management Practices for Golf Courses – Volume 1, Issue 1 (January 25, 2016)

This new weekly newsletter from Cornell turfgrass specialist Frank Rossi will run until the ShortCUTT newsletter starts its 17th season in late March.

In this issue:

  • Easy way to learn more about your soil.
  • Take the ‘Best Practices’ quiz and assessment.
  • A look at insecticide chemistry.
  • Looking for progressive approaches to water quality protection.

ShortCUTT podcast year-end wrap up

Busy season. We got a little bit behind on the podcasts. So if you’d like to find out what you missed this fall, feast yourself on these podcasts:

Podcast also available via iTunes.

If you’d like to subscribe via RSS, the feed is here:

To receive the weekly ShortCUTT newsletter, join NYSTA or subscribe directly.

For more turfgrass resources, visit the Cornell Turfgrass Program website

Comments or questions? Use the comments below (they are moderated and so they won’t appear immediately) or email Craig Cramer (

Free iBooks will make your lawn ‘green’

ibook coversWith the grass finally starting to green up in the Northeast, two new iBooks from Cornell University will help you turn your lawn into an environmental asset — as well as a beautiful place to relax and play.

Lawn Care: The Easiest Steps to An Attractive Environmental Asset  – This iBook features seven short how-to videos, photo galleries, interactive images and concise, easy-to-understand steps to cultivate a healthy lawn, including how to mow your lawn less and enjoy it more. It also details more advanced techniques, including best feeding strategies and how to cope with weeds, pests, diseases and soil compaction.

Turfgrass Species and Variety Guidelines for NYS  – Thinking about starting a new lawn or renovating an old one? This iBook will help you choose the grass species and varieties best adapted to your growing conditions, lawn care plan and expectations.

The Cornell Turfgrass Program, the Cornell Garden-Based Learning Program, and the New York State IPM Program all contributed to these iBooks.

Professional turf managers will also benefit from these recently launched Cornell websites:

Turfgrass and Landscape Weed ID – The first step when managing weeds is to know what weeds you have. This mobile-friendly site makes it simple to identify common New York weeds based on easily observed traits.

Sports Field Management – Everything sports turf managers need to create safe playing fields, from managing soils and choosing grasses to mowing and fertilizing strategies and pest management. Interactive management schedules provide timely advice.

Best Management Practices for New York State Golf Courses – Research-based, voluntary BMP guidelines are designed to protect and preserve our water resources that enhance open space using current advances in golf turf management.

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