The 5 commandments of sustainable sports turf management
By Martin Kaufman, CSFM
Sustainability has become a trendy word used by the media and politicians as our society has become more familiar with terrorism, recessions, and environmentalism. I actually like this word as I feel like it embodies practices that I grew up with on the farm in the Midwest. Hard work (effort), ingenuity (recycling), coupled with science and math usually won the day. My Dad grew up on a dairy farm and earned his agronomy degree from The Ohio State University. I remember helping him plant corn and soybeans with endophyte-coated seed. Soybeans were new and no-till planting was fairly new. As I learned the basics and experienced the difference in how my Dad did things and how my Grandfather did things, I started to realize there is more than one way to do it; however some basic priorities still prevail.
Here are some prioritizations I have developed as I try to share with customers some practices available for use when they choose to distribute their resources. As you may be aware there are many forms of a particular cultural practice and diversification is usually best. When it comes to building a maintenance program for your athletic field, that is soundly supported year after year, I believe these five commandments are stated in sequencing priority order, one being the most important and five being the least. All practices are important; however to maximize return on investment (ROI) the investment in the first dictates significance of ROI from the second and so on. Many times I see significant investments made in priorities four and five with a poor ROI because there is a paltry investment in priorities one, two and three. Another way to look at this recommendation may be in the form of goal setting.
Monthly aerification (any form)
Monthly fertilization (annual soil test)
Monthly consider weed/pest control
Consider topdressing/thatch control
You may have noticed I did not mention irrigation, a specific kind of mower or aerifier nor did I mention a specific kind of fertilizer, chemical or thatch controlling device. I will use the remainder of this article to define some of the thoughts behind these prioritizations as well as define what they are intended to portray.
What does consistent mowing mean? Mowing no more than 1/3 of the leaf blade off, mowing often enough to keep the 1/3 rule, mowing with sharp blades at a slow enough ground speed so as to actually cut the leaf rather than tear or rip it. Mowing with four different rotating patterns. Mowing as high a height as tolerable and understanding that mowing manages sunlight and photosynthesis. To quote from the book, Sports Fields 2nd edition by James Puhalla, Jeffrey Krans, and J. Michael Goatley Jr.: “…a turf that is neglected several months at a time cannot be brought to peak playing conditions by one or two low-height mowings just before the season starts.”
One of the sayings I have found myself passing along is that “if we succeed or fail today it is not because we succeeded or failed today, it is because we succeeded or fail 3 to 6 months ago.” So what does consistent mowing provide? Relief when things don’t go as planned (skipping a mowing). Healthy turf when clean cut rather than ripped (less stress). Increased density for safety, looks, wear tolerance, and playability. Reduction in weeds, diseases, and pest problems. Increased soil microbial activity and nutrients available (soil biology and health). Survival of environmental extremes or stresses like drought, flooding, heavy traffic, constant traffic, heat or cold.
Why entertain a goal of monthly aerification? What does aerification actually do? Create pore space in the soil. Why is pore space important? A healthy soil has 50% pore space and 50% elements, plant parts and debris or organic matter; 50% of the pore space should contain water while the other 50% contains air. When traffic and standing water compact the elements, plant parts and debris or organic matter, pore space is reduced or eliminated which reduces or eliminates the field holding capacity (storage ability) for water and air. What happens when there is no water and/or oxygen in the soil? Limited or no plant respiration! What is respiration and why do we care? Respiration is conversion of carbohydrates to ATP (adenosine triphosphate). What else makes ATP? Photosynthesis. Why are photosynthesis and respiration important? Energy conversions for energy utilization. No photosynthesis or no respiration means no energy and death will result!
Time for another quote from Sports Fields: “…seek first the health of the turf and its enfolding culture, and all the rest (playability, economy, aesthetics) will be added onto it.”
The Soil Food Web, a sustainable cycle that begins and ends with “dead material” that is used by microbiology to store, release and manage chemistry. Ever heard of lichen, bacteria, fungi, protozoa, nematodes, and mites? Soil organisms that make nitrogen available to plants are predators of fungi or bacteria. The interaction of bacteria and their predators and fungi and their predators produce as much as 80% of the plant available nitrogen that occurs in the soil.
So how does fertilizer get into the plant anyway? Water solution. What do we know about some of our weeds and less desirable grasses? They don’t require the same conditions as our preferred grasses do they? Many times these weeds and less desirable grasses do well with less pore space or oxygen. Why is that? When we converse about chemical elements in the soil we usually realize that ratio balance is as important as individual quantity. pH is usually affected by these ratios and sometimes the pore space as this may affect anaerobic and aerobic activity that does bind or solubilize elements thus restricting or making them available. Just as different plants prefer different pH they also thrive or struggle in different microbiological ratios. For instance finding fungi in the forest is not uncommon. Trees, particularly conifers, prefer a higher fungus to bacteria ratio. Weeds enjoy 100% bacteria or a low level of fungi to bacterial ratio. Desirable grasses and row crops tend to do well with a balanced ratio of fungi to bacteria.
The point is, mineralization only occurs because of biological processes. When biology is functioning properly, water and fertilization use is reduced and plant production is increased. Bacteria convert ammonium to nitrite and then to nitrate by removing hydrogen and then replacing it with oxygen. Nitrate does not exist in the soil without the soil microbiology functioning. What do fungi do? Fungi retain and solubilize nutrients to the plant in exchange for protein sugars. Fungi actually create pore space for water and oxygen and compete with pathogens that may cause disease.
Why are Mowing and Aerification at the top of the list? Because these two cultural practices heavily influence biological processes more than any other cultural practice. Aerification can increase your field holding capacity for rain on non-irrigated fields or the pore space for oxygen on an over-irrigated field.
Please consider the cost of a soil test versus the cost of any fertilizer product. Documenting the test results and interpretation of the soil samples annually creates a trend that can be used for sustainability in your maintenance program. I go to my physician once a year for a physical and blood test. That is what a soil test is for your turf. Diet, exercise and medicine are used to manage my health both acutely and long term. These cultural practices usually will dictate how sustainable my life is or how quickly I recover from stressful environmental conditions.
In turf I prefer the private labs with Mehlich III extraction methods on P2O5, categorization of Anions, Exchangeable Cations, Trace Elements and a Base Saturation percentage. However, I keep the formula ready to interpret the Extension Lab results from Mehlich 1 so I am looking at apples to apples so to speak. Pay attention to (PPM) parts per million and (lbs./A) pounds per acre. Many folks like to say “fertilizer is fertilizer” or “nitrogen is nitrogen.” I would point out that paying attention to what else is in the bag or the tank has just as much if not more of an effect on the results. If there is something in the mix that the soil already has plenty of then you run the risk of pollution or triggering a chemical or biological process you didn’t intend.
What is the salt index value of the material? What form of nitrogen or potassium is it? What percentages of sulfur, iron, magnesium or calcium are in the product as well? How does that influence your pH, elemental ratios and biological processes? 17-17-17 is inexpensive and the correct tool in many situations. However, take the time to take a look at what it really is: diammonium phosphate, urea, and muriate of potash. These are some of the higher valued salt index forms of nitrogen, phosphorus and particularly potassium. This does affect your soil chemistry and biological processes. Deficiencies must be corrected and elemental relationships maintained. This will allow the soil microbiology to do the work for you. It does matter if you use promag, sulpomag, high cal lime, dolomitic lime, or gypsum. Apply what the soil needs and not what it doesn’t need for the crop you are sustaining.
What about pest management?
Weeds, insects, diseases, people, equipment. Time for another quote: “Proper fertility, irrigation and cultural management decisions can greatly reduce the incidence of pests in athletic turf.” I will add another quote I seem to use often, “just because you can doesn’t me you should.” Do you need that pesticide? Have you crossed the tolerable threshold of (IPM) Integrated Pest Management? Believe me, I use pesticides. However, using pesticides needs to be reserved for specific needs rather than cheap acute solutions. These herbicides, insecticides, fungicides, etc., have an influence on soil microbiology. How do you think pesticides are broken down any way? Microbiology. Which would you rather your soil microbiology be working on? Serving water and nutrients to your grass plant and breaking down organic matter or breaking down the latest pesticide applied? Remember a fungicide is most likely killing the good guys too.
Topdressing and thatch control
This practice usually needs to be employed because you have invested so well in the previous four commandments. Strong healthy turf is going to produce thatch and invite pest issues such as disease and insects (no weeds though). Topdressing, dethatching, verticutting and slicing among other methods may assist microbiology in managing the successful ROI in sustainable cultural practices. I have seen many sports fields topdressed that are not being mowed consistently and certainly are not aerified frequently. The result is a beach volleyball court. You could argue verticutting be lumped in with consistent mowing and I wouldn’t mind. Remember that each cultural practice has a purpose and is building on the investment made in the practice performed previously.
Martin Kaufman, CSFM, is the grounds and sports field manager for GCA Services Group.