12 SportsTurf | April 2010 www.sportsturfonline.com

OVER THE PAST SEVERALYEARS budgets for turfgrass main-tenance have been reduced dramati-cally. Athletic field managers haveall had to adjust to the struggles

associated with maintaining high quality turfwith less money. One could argue that sportsturf managers are affected more than any othersector of the industry during these trying times.While dollars for field maintenance continue todecline, demands on field use do not.

To conquer these challenges from a weedcontrol perspective, sports turf managers mustcomprehensively evaluate their management pro-grams to determine where valuable budget dol-lars should be spent. The steps presented belowcan be used as a guide for making weed controldecisions on a restricted budget.

PRIORITIZEThe first step in effectively controlling weeds

on a restricted budget is to realize that any pro-

gram implemented most likely will notbe comprehensive. While the entirefacility may have been treated in thepast, with fewer dollars in the budget itis critically important that sports turfmanagers determine what parts of theirfacility need to look the best (i.e., befree of weeds). Many sports turf man-agers grade these areas. For example,game fields for varsity sports may bedeemed A-level areas, practice fieldsmay be deemed B-level areas, and thoseused for band or physical educationclass may be deemed C-level areas.

TIMINGOnce key areas have been identified,

it is important to determine whenthese areas need to look the best. If fallsports predominate, weed control inearly spring becomes less important.This especially rings true for thosemanaging bermudagrass fields in thetransition zone. There are significantcosts associated with fall overseedingincluding the cost of seed, fertilizer,water (in some cases), labor for mow-ing, and herbicides for weed control.Chemically removing the overseededturf in spring can cost as much as $150per acre, in addition to the cost ofselective winter annual broadleaf andgrassy weed control.

On fields with minimal spring play,consider not overseeding in fall andcontrolling weeds with a non-selectiveherbicide in spring while the bermuda-grass is still dormant. This strategy willprovide economical control of winterannual broadleaf and grassy weeds witha single herbicide application. Lack ofcompetition from the overseeded turfwill also allow bermudagrass to recu-perate from fall traffic more efficientlyin spring. Research conducted at theUniversity of Tennessee in 2009 foundprograms delivering non-selective her-bicide applications to dormantbermudagrass to provide more effectiveand economical weed control thanthose incorporating fall overseedingand selective herbicide applications.

FieldScience | By James T. Brosnan, Ph.D. and Greg Breeden

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Sports turf weed control on a budget

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PRESSUREAnother important step in controlling

weeds with less money is to determine theamount of weed pressure that warrants anherbicide application. This is directly relatedto the expectations of field users and thescope of the budget provided. While a 100%weed-free stand may have been the standardin the past, budgets may require that this beshifted to 85% or 90%. Another option is toensure that A-level areas are 100% weed-free, while B and C-level areas remain at 70-80%. These adjustments may help stretchdollars for weed control further.

CULTURAL PRACTICESTO MAINTAIN DENSITY

A dense stand of vigorously growing turfis the best defense against weed invasion.Weeds only invade turf stands if there is avoid in the canopy in which to do so. Withfewer budgetary dollars available for weedcontrol, sports turf managers should thor-oughly evaluate their cultural practices toensure that everything possible is being doneto maintain turf density under traffic.

Practices such as selecting traffic tolerantcultivars, applying fertilizers to meet soil testrecommendations, sufficiently irrigating tomeet plant needs, mowing at a proper heightof cut, aerfiying regularly, and applyingplant growth regulators all serve to maximizeturf density and consequently reduce thelikelihood of weed infestations. In a world ofsmaller budgets, implementing cultural prac-tices to maximize turfgrass density should bethought of as preventative weed control.

CALIBRATIONCalibrating spraying equipment is proba-

bly the easiest way to save money when budg-et dollars are limited. Studies have shown thatover 80% of licensed pesticide applicatorshave calibration and/or mixing errors greaterthan 5%. These errors have been found to

range from a 40% under application to a60% over application, resulting in over 4 mil-lion dollars in lost revenue.

Sprayers should be calibrated at least onetime per growing season, with nozzleschanged regularly. Taking the time to checkthat spraying equipment is calibrated andoperating properly will ensure that dollarsare not wasted on improper herbicide appli-cations.

SELECTING THECORRECT PRODUCT

Proper herbicide selection depends onmany factors including the weed requiringcontrol, the stage of weed maturity, and thespecies of turfgrass in which the weed hasinvaded. New herbicides are entering themarketplace with a focus on broadening theweed control spectrum of a single herbicideapplication. These products typically com-bine two or more herbicides that have beensold individually into a single formulatedproduct. Examples include Solitare (sulfen-trazone + quinclorac) and Onetime (quinclo-rac + MCPP + dicamba). Both of theseproducts offer postemergence control ofcrabgrass and various broadleaf weeds with asingle application. Using a product with awide weed control spectrum will reduce thenumber of herbicide applications requiredduring the season.

PREPARING FORLOSS OF MSMA

The loss of an effective, economicalpostemergence herbicide like MSMA willmake weed control even more difficult withrestricted budgets. Questions about legalapplications of MSMA still linger through-out the industry. According to the EPA, reg-istrants of MSMA for use on sports turf lostthe ability to sell the product on December31, 2009; however, distributors will be ableto sell products purchased before December

31, 2009 until December 31, 2010. AfterDecember 31, 2010 existing stocks ofMSMA can legally be used for weed controlon sports fields until they are exhausted pro-vided that these uses comply with the EPA-approved label and labeling of the affectedproduct.

Considering that the window to legallyapply MSMA is closing by the minute,sports field managers challenged with dallis-grass infestations should place top priorityon controlling these problems as soon aspossible. Researchers at the University ofTennessee are continually evaluating newcompounds, as well as combinations of exist-ing compounds, that will help soften theblow of the EPA restrictions on MSMA. Tofollow the latest research being conducted atthe University of Tennessee, visit http://ten-nesseeturfgrassweeds.org.

All aspects of turfgrass management,including weed control, become challengingfollowing budget cuts. Taking the time toevaluate why certain practices have beenimplemented in the past should help identifythe key components of the maintenance pro-gram requiring attention (and budget dol-lars) in the future. ■

Dr. James T. Brosnan is assistant professor-turfgrass weed science at the University ofTennessee; Greg Breeden is weed science exten-sion assistant at UT.

FieldScience

14 SportsTurf | April 2010

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Proper herbicide selection depends on many factors includingthe weed requiring control, the stage of weed maturity, and thespecies of turfgrass in which the weed has invaded.

Dr. James Brosnan, University of Tennessee,Technical Editor of SportsTurf.

of good soil management dealswith air, water and carbondigestion (physics and biology),is soil testing really about fertil-ity?

The intention is to changesoil physics and improve theenvironment for soil biology.After more than twenty yearsof soil testing, tens of thou-sands of soil tests on hundredsof sites, I have never seen theprocess fail if the turf managersticks to the basics. I have,however, repeatedly been toldthat it cannot work, “you can’tchange soils physically bychanging soils chemically”,“there is no research to provethis”, “an acre inch is two mil-lion pounds of soil much toomuch to change…” The truthis you can change soils physi-cally by manipulating the soilchemically and you better ifyour soils are out of balanceand you hope to produce bet-ter turf with fewer inputs. Weare not changing clay to sandor sand to silt and we are notconcerned about the entire twomillion pounds of soil in theacre inch, we are only con-cerned about the four thousandpounds or so that make up thenutrient profile particularly cal-cium, magnesium and potassi-um that affect soil flocculationwhich impacts soil biology andthat we can change. What weare really focused on isBiological Soil Management.

According to the workingmodels presented by Dr.

FOR OVER TWENTY YEARS I have been staring at soil tests, writing reports and recommen-dations. And for over twenty years I have seen, sports turf managers, and golf course superin-tendents make changes to their properties. Clearly they have produced better turf but moreimportantly they have made changes to their soil profile. They have improved drainage,strengthened rooting, increased plant recovery and they reduced fertility inputs. Why?

Because they have soil tested and their soil testing programs have helped them to discover that improvingthe physical structure and biological profile of the soil is the precursor to good soil and plant fertility.

The four basics of good soil management are: Air Management, Water Management, DigestionManagement and finally Nutrient Management, in that order. Air space in the soil allows for good watermovement, without air in the soil roots will not survive and beneficial soil micro-organisms will not prolif-erate. With too much water an anaerobic condition will prevail and both roots and microbes will die off.With good air and water movement through the soil profile you will create the environment where benefi-cial soil microbes can freely multiply and in the process carbon is digested down to humus — the ultimatebreak down of organic matter in the soil. This humus is then used as a microbial food source to generateeven more biological activity. It is the back bone of the carbon to nitrogen cycle in the soil, producing freeand needed nitrogen to the plant without all the side effects of synthetic applications. If and only if theenvironment for microbial digestion is present in the soil will nutrient mobility take place. Microbes “eatat the table first” and all nutrient mobility from the soil is done through microbial degradation. A goodsoil testing protocol allows the turf manager to manipulate the soil physically, by balancing basic cationsand relaxing soil particles just enough to allow better air and water movement through the soil profile.This builds a better environment for soil micro-organisms to do their job of digesting carbon, releasingnutrients into the root zone and providing buffers for water, temperature and pathogen attack. So, if 75%

16 SportsTurf | April 2010 www.sportsturfonline.com

SOIL TESTING IS NOT ABOUT FERTILITYAt least not exclusively!

FieldScience | By Joel Simmons

After more than twenty years of soil testing, tens ofthousands of soil tests on hundreds of sites, I have neverseen the process fail if the turf manager sticks to the basics.

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18 SportsTurf | January 2010 www.sportsturfonline.com

FieldScience

18 SportsTurf | April 2010

Albrecht at the University ofMissouri, and Dr. Bear atRutgers University we arelooking to balance the basicsoil cations and striving for aprofile that presents roughly68% calcium, 12% magne-sium, 5% potassium, 2 %sodium, 3% trace elementsand 10% hydrogen. When acolloidal soil moves to thesepercentages the soil physicallyworks better. Air and watermove through the profilemore efficiently building anenvironment where soil biolo-gy explodes and the nitrogencycle increases. In this modelif we can achieve 10% hydro-gen we will always have a pHof 6.3 which is the point atwhich we find maximumpotential nutrient mobilityacross the entire nutrientboard. These percentages arefound in the base saturationsection of a complete base sat-uration soil test and can easilybe manipulated by addingwhat is deficient and knock-ing off what is excessive.Unfortunately, not all soiltests show a complete basesaturation where all six cationgroups are present, calcium,magnesium, potassium, traceelements, sodium and hydro-gen. Too often a soil testinglaboratory will show a limitedspectrum of soil cations orthey will add up to somethingmore that 100% which is nota true base saturation andmakes building a quality rec-ommendation all most impos-sible.

The following base satura-tion was found on a soil testof a sports turf client: 35%Ca; 45% Mg; 2% K; 5% Na;3% traces and 10% hydrogen.He was not able to aerify thesoil because it was too hard

20 SportsTurf | April 2010 www.sportsturfonline.com

FieldScience

and the metal tines of the aeri-fier would not penetrate thesoil. When it rained the soilwould not drain for days, hehad very poor rooting, seedgermination was weak and hehad to apply over 8 pounds ofsynthetic nitrogen per 1000square feet to the site each yearsimply to maintain color.When I asked how his soil washe responded by saying “it’snot my soil, I tested it and thepH was 6.3!” He had over a1700 pound deficiency in cal-cium, a thousand pound excessof magnesium, low potassiumand high sodium. I recom-mended three applications ofhigh calcium limestone at arate of one ton per acre, sepa-rated by a few months, alongwith a lot of potassium sulfate.After the second application oflime I called him and asked ifhe was able to aerify the prop-erty and he reported that hecould not. So I asked him ifhe had seen any difference andhe did say that he thought theyhad reformulated his fertilizerbecause it was working a lotbetter. With better soil biolo-gy fertilizer will work better!One year later he called andtold me that he had run hisaerifier over this site and didnot break a single tine, whichwas uncommon prior to mak-ing the soil adjustments, so heran the machine off the treatedarea to an adjacent soil thatwas not treated and as soon ashe hit that soil he broke themachine into pieces! Hereduced his nitrogen inputsdown to around two poundsper 1000 square feet per year,drainage was no longer a prob-lem, rooting was strong anddeep, recovery was excellentand seed germination when heneeded it was very good.

SportsTurf 21www.stma.org

When staring at as many soil tests as I doit sometimes becomes hard to see the forestthrough the trees but a client once told methat when the light bulb finally went off forhim was when he realized that base satura-tion was always 100%, no more and no less.If a soil test shows more or less than 100%base saturation it is not a true base saturationtest which is the key here. Understandingthat it is always 100% makes it easy to seethat if something is high it can be exchanged(cation exchange capacity) by replacing itwith what is low. In the previous examplemagnesium was driving the soil and calciumwas low so by adding the proper amountand type of calcium we were able to drive offthe magnesium which was tightening the soiland affecting soil biology.

Base saturation is only one of many toolsthat we use to manage soil profiles and onsome soils it is not as strong a tool, such aslow CEC sand based soils, but the tool canstill give us direction. On these sites the suf-ficiency levels of nutrients is clearly our firstfocus. I have become a big fan of the watersoluble paste extract test to give me evenmore information and help me answer somequestions that may not be easy to answersimply by reviewing the standard soil tests. Iuse Logan Labs (www.loganlabs.com) for mylab work but there a number of good labsproducing complete base saturation soil tests.A complete base saturation soil test willnever lie to you it may tell you that sodiumis driving the soil like out west or calcium onthe calcareous soils of the mid west or evenaluminum like in some of the gumbo soilsdown south. A good soil testing protocolwill give you the map and directions on howto affect physics which will affect soil biolo-gy. Oh and by the way all of this improvesnutrient mobility! ■

Joel Simmons is the President ofEarthWorks Natural Organic Products andSoil First consulting and teaches the Soil FirstAcademy all across North America. He holds aMasters Degree from Penn State Universityand is a former Penn State County ExtensionAgent and Instructor of Soils at RutgersUniversity. He may be reached in front of hiscomputer at joel@soilfirst.com most likelyworking on yet another client’s soil test.