FIELD SCIENCE

Iutrient management planningfor sports turf is both an art anda science. More than just a fer-tility program, it is a site specif-ic management tnol. Nutrient

management planning integrates the use ofplant nutrients and cultural practices necessaryto achieve optimum turf health. The amount,form, placement, and timing of nutrients andsoil amendments make up the nutritional plan.

Cultural management practices such asmowing, inigation, aeration, and turfgrassselection enhance its efficacy. It is appropriatefor all sports turfuses. Whether you are grow-ing cool or warm season turf grass on native,sand based or modified suil, nutrient manage-ment planning permits efficient sports fieldmanagement and protects water quality fromnutrient pollution.

In many areas, Nutrient ManagementPlanning' came about as result of excess levelsof nitrogen and phosphorus in our surface andground water resources. Many states,provinces, and local governments now havelaws or programs regulating the sources andamounts of nutrients contributing to non pointsource pollution of our water resources. Theoverall goal of many of these programs is to

.~

8 July 2007

protect and improve water quality by promot-ing the efficient yet responsible use of fertiliz-ers and soil amendments. Also, an effectivenutrient management plan adds value throughbetter results and cost savings.

Fate of nutrientswhenever fertilizer and water are applied

to a sports field, there is the potential for somenutrient loss to occur. To illustrate this process,here is a simple explanation: Precipitationfrom rain (or from a sprinkler head) isabsorbed by the soil to become ground wateror runs off to a body of water, such a.'l a riveror ocean. 'Water is returned to the atmosphere(by evaporation or through transpirationthrough the turf), condenses and returns toearth as precipitation.

What happens to the nutrients in the envi-ronment? Nutrients go into solution 'with thewater. Some of the nutrients are used by theplant or stored in the soil for future use.Unfortunately, some of the nutrients may belost through leaching into the ground water orby surface runoff, erosion (A dense stand ofturfgrass can limit nutrient runoff). Nitrogencan even be volatilized directly into the atmos-phere, One of the goals of nutrient manage-

meru planning is to minimize nutrient loss,Nitrogen, phosphorus, and potassium are

referred to as macronutrients because they areused by plants in large quantities. (Micro-nutrients are elements that are essential forplant health, but used in very small quantities.]Of the three macronutrients, nitrogen is themost unstable, meaning that it can change itsform easily. That is why nitrogen is not usuallymeasured on a common soil lest. Phosphorusbinds with the mineral compounds and theclay fraction in many soils and is less mobilethan nitrogen. Both nutrients can cause con-tamination when moved away from their tar-get by erosion or leaching and become con-centrated in a body of water. Potassium is theleast mobile, meaning that once applied to thesoil, it stays in place. Rarely does potassiumcontamination cause environmental problemsin surface or groundwater.

Getting startedA documented nutrient management plan

is best. Start with accurate area measurementsbecause a nutrient management plan isdependent upon some amount of materialneeded per unit of area. Obtain a site mapshowing the locations of all surface waters

Continu.ed 011 page 17

www.greenmediaonline.com

{uch as drainage ditches, streams, and ponds• and indicate topographic features such assteep grades, hills, and low areas. Because~ater moves downhill, this information willHelp you understand where the water andduments will likely end up_ Include on thismap all pertinent soil texture information.• Identify the species of turfgrass growing inthe turf stand. If you know the types of turf-grass in your field, and understand its require-ments, your nutrient management plan will~ave a better chance for success. Informationabout the nutrient requirements for your 8pe-~fic turfgrass is available through your localcooperative extension service. Be sure to doeu-them the health and conditions of your turfstand because this information will help youevaluate the effectiveness of your plan.

Soil sampling and testing is the next step inthis process. A basic chemical soil lest canquantify the levels of available phosphorus,Rotassium, and rnicrunutrients. The chemicaltest IYiIl also determine the soil pH, cationexchange capacity and base cation saturation.

his information provides insight into howefficiently your soil stores and makes availablen~trients that the turf needs.

All of the information is critical for calcu-lating what soil amendments and nutrients areneeded (if any) as well as the amounts. Oftenthe soil lab will make lime and fertilizer rec-ommendations including rates and timinglfased on the information that you providethem when you request the test.

A separate test for soluble salts can indicateif excess fertilizer or potentially damaging lev-els of salts are present in the snil. This is help-ful for selecting appropriate treatments u,~ingsoil amendments to move the excess levels outof the root zone. Other tests include testingyour irrigation water to check pH and detectthe presence of soluble salts, bicarbonates andminerals. Plant tissue testing is another way ofmeasuring nutrient levels within the plant.Tissue tests will help you spot excess or defi-cient nutrient levels in the soil.

Testing for soil physical properties includ-ing percentages of sand, silt, clay as well aspercent of organic matter can be useful to

assist in determining how well the soil willhold on to nutrients. Sandy soils that drainwell often do not hold moisture or nutrientsvery long. Soils with higher percentages ofclay and organic matter have more moistureand nutrient holding capacity. Use this infor-mation to indicate where the different soil tex-tures are on your soil map. Your soil-testinglaboratory will instruct you in how you shouldtake samples, the number of samples to takeper acre as well as the depth at which youshould take them.

Custom.izing your planOnce you have collected and documented

the information on what you have and whatyou need, you are ready to customize yoursite-specific nutrient management plan. Forexample, a low maintenance ballfield in a

schoolyard will have a much different planthan a professional stadium field. This iswhere nutrient management becomes an art.

Consider the nutrient tools available. Assports lield managers, we are fortunate to havea wide variety of fertilizer options dependingupon our management needs. Simply put, fer-tilizers can be grouped into two categories:quick release and controlled or slow release.This distinction is important because it relatesto plant response and longevity in the rootzone.Each category may be derived from naturalsources or synthetic processes. Quick releaseand slow release fertilizers commonly refer tothe nitrogen source used, although it can alsoinclude phosphorus and potassium sources.

Quick release fertilizers are water soluble,inexpensive per pound and provide rapidplant response. Because of their solubility, theytend to leach out of the root zone easily andcan cause foliar burn. These materials can pro-vide desirable results when used at low rateswith frequent applications. By combining thesefertilizer components together in different pro-portions it is possible to create a variety ofcomplete water soluble fertilizer formulations.

Controlled release fertilizers include prod-ucts formulated for slow release nitrogen char-acteristics. The release rates vary between thedifferent products. Controlled release fertiliz-ers usually cost more per pound for the nutri-ent. The turf response, color, and growth areslower than water-soluble fertilizer. Theadvantage is that more material can be

www.sportsturfmanager.org SportsTurf 11

FIELD SCIENCE

applied with less foliar bum, so fewer applications are needed.Common examples of controlled release sources include: coated fertil-izers, where the particles are coaled in a permeable "jacket" and thenutrients diffuse out of the "jacket" at a controlled rate.

Natural organic products derived from animal and vegetablebyproducts arc low in nutrients, but can be applied in large volumewith very [ow risk of foliar burn. Synthetic organics such as

THE GAME MUST GO ON.An Airfield is the ultimate sports turf

drainage system whether you areplaying on natural or artificiallurf.

Artificial Turf Benefits:"Drains remarkably faster-ReduGas installatkm lime-Reduces G·Max-Eliminates rubber migrationoEliminates standing wafsr-Strong enough for vehicles'Below enlire playing surfece'Air void for heating and cooling-Allows flushing and sanitizing'Maintains level playing surface

Naturel Turf Benefits:-Orains remarkably faster'Reduces installa~on time'Reduces Irrigation requiremenls-El<!ends playing season-Eliminates standing waler'Reduces maintenance costs'Below entire playing surface'Superior perched water lahle·Great .....root mass

."""

Fill in 128 On reader service form or visit http://oners.hotlms.com!13971-128

12 July 2007

•

Isobutyraldehyde Diurea (IBDU 31-0-0) and Urea Formaldehyde(DF 38-0-0) and Methylene Ureas are widely used and all are 8

source of slow release nitrogen. The release rates of all of these mati:rials are dependent upon fertilizer particle size, temperature, mois-ture and soil microbial aclivity.

For many sports field managers, cost seems to be the limiting factorwhen choosing a nutrient source. By understanding the costs involvedwith making a fertilizer application, as well the longevity of the nUl~enrs in the soil after the application, products with a higher cost perpound may be a better value and deliver more consistent results.

Regardless of the nutrient sources you select, good cultural man-agement implements your nutrient management plan. For example,urrfgrass needs water for growth, good health, and vigor. Inigationmanagement complements your nutrient management plan. Begirt byconducting an irrigation audit and inspection of your inigation systemto determine how well it functions. The audit will show you how uni-form the water is being distributed so that you can make repairs orimprovements. The process includes measuring how much water vol-ume is being supplied by the system in a given period of time.

The audit will also help you schedule water usage by calculatinghow much water your soil can hold, the amount of water the turf need~and how much is lost through evapotranspiration. To avoid leaching,puddles and runoff, make sure that the amount of irrigation being deliv-ered is less than the rate at which water infiltrates and percolatesthrough the soil.

The soil texture of your field figures prominently in your plan pa.r-ticularly in relationship to y01ll" irrigation methods. For example, sandysoils receiving frequent irrigation might be prone to nitrates leachingpast the rootzone. In another example, heavier textured soils such as asilt or clay loam could erode during a thunderstorm losing phosphorusbound to the soil particles.

The idea is to keep the nutrients where we want them so they canbe used efficiently by the turf, and not lose them in the groundwater,streams and ocean. Whether you have an irrigation system or rely sole-ly all rainfall, the form and frequency of your nutrient applications hasan impact on the effectiveness of your nutrient management plan.

Aeration enhances nutrient management by increasing the amountof pore space in the rootzone for air and water. This process increases

Continued onpage 14

www.greenmediaonline.com

FIELD SCIENCEwater infiltration into the soil and helps reducerunoff. Aeration facilitates root uptake by therurf and creates a more habitable environmenttor the soil organisms.

Cuol and warm season turfgrasses eachhave periods of growth and dormancy. Planyour nutrient program around the nutritionalrequirements of your turf stand and optimumgrowth periods for your particular species. Acool season turlgrass best management prac-lice is to overseed with improved cultivars.You can select cultivars with genetic charac-teristics such as darker color and beuer diseaseresistance that require fewer nutrient inputsand add biodiversity to your turf stand. Listsof improved cultivers suitable for your geo-graphic area are available from the NationalTurfgrass Evaluation Program (NTEP) on theweb at wwwntep.org .

Mowing is the most common cultural prac-tice that. occurs un sports fields at all levels.Follow the best management practices for

mowing with sharp blades at an acceptablemowing height that is specific for the turfspecies, following the 1/3 mowing height rule.The question of whether or not you will leaveclippings will factor into your nutrient man-agement program, as the clippings when leftreturn a residual amount of nitrogen, phos-phorus and potassium to the soil to be brokendown by microorganisms and used by the turf.

Nutrient management is about good stew-ardship and working smarter, when our mis-sion is to produce safe, playable, and attrac-tive sports fields, it helps to deliver greatresults. It is good for us individually and as anindustry to do our part to help our environ-ment become healthier through careful plan-ning and responsible actions .•

Dan Savard, CSFM, CGM is also a DelawareCertified Nutrient Consultant and manages lhe ath-leticfacilities and ground.1at the Saiesianum Schoolin Wilmington.

John Mascaro's Photo QuizCan you identify

this sports turf problem?Problem: Brown spots on soccer field

Turfgrass Area: Soccer Field

Location: South Portland, Maine

Grass Variety: Kentucky Bluegrass

Answer toJohn Mascaro's Photo

Quiz on Page 51John Mascaro is President

of Turf-Tee International

14 July 2007 www.greenmediaonline.com