Sports Turf NutritionA Special Diet For High

Ground·driven rotary spreader.

Statisticians keep records on somestrange yet important facts. For ex-ample, people spend more than a

third of their life sleeping, more than a fourthof it working or commuting to work, and near-ly a tenth of it eating. With all that time in-vested we should concentrate on makingthe most of it.

If these same statisticians evaluated thedaily routine of sports turf managers, theywould no doubt find a large portion of theirday is spent on the basics of mowing, fer-tilization and irrigation. There are other, moreexciting aspects of the job that draw theirattention away from the basics, but the bestsports turf managers remain vigilant to theirskill in the basics.

To the novice, fertilization seems simple,yet it is the most complicated of the basicmanagement practices for sports turf. Fer-tilization provides the diet of the turfgrassplant. A poor diet results in weak turf in-capable of recovery from the wear inflict-ed upon it by sports. A rich diet results inlush turf that is vulnerable to diseases andinsects, requires more mowing than neces-sary, and favors foliage growth at the ex-pense of important root growth.

PTO·powered pendulum spreader.

24 sportsTURF

The sports turf manager must determinethe amounts of important nutrients need-ed by high-use turf and the rates at whichthey need to be replenished. These amountswill typically be different than amounts con-sidered adequate for utility or lawn turf. Turfunder stress utilizes nutrients differently thanturf in a standard lawn situation. Withouta special diet, sports turf is unable torecuperate and will deteriorate with repeatedfield use.

The amount of nutrients required by sportsturf is greatly influenced by the conditionof the soil. As mentioned in the article inthe September issue by Eliot Roberts andFred Grau titled The Living Soil, clay andhumus particles in the soil serve as storageand exchange sites for nutrients. Theamount of clay and humus in the soil willaffect the amount of fertilizer that needs tobe applied during the growing season.Greens, tees and some athletic fields areconstructed largely of sand to improvedrainage and prevent compaction. Theseareas typically require more frequent ap-plications of nutrients than clay/loam soils.

The acidity or alkalinity of the soil can alsoimpact fertilizer rates. The measurementused to describe soil acidity/alkalinity is pH.Even though sufficient levels of nutrientsmay be present in the soil, they may notbe fully available to the turfgrass roots whenthe pH is below 5.5 or above 7. Sports turfsoils should be amended to be within thisrange so the full benefit of fertilizer is ob-tained. It should also be noted that acidityor alkalinity can hamper the decompositionof thatch and organic matter in the soil.

To lower the pH in alkaline soils or sitesirrigated with alkaline water, apply sulfurin the fall or spring after aeration. Fertiliz-ers containing sulfur can also be used ina maintenance program to slowly reducethe pH of alkaline soils. Some of these areammonium sulfate, sulfur-coated urea,potassium sulfate, sulfate of potash and fer-rous sulfate.

The pH of acid soils can be raised by ap-plying lime or dolomitic limestone to the turfin the spring or fall after aeration. Fertiliz-ers containing sulfur should be avoided onturf with acid soil conditions. Correcting soilpH problems may take a series of applica-tions of soil conditioners.

Soil testing is the first step to achieving

a balanced turf diet. Every sports turfmanager should have a soil probe in his ve-hicle to pull plugs for soil testing. Pull threeor four plugs from each critical turf site andmix them together in an envelope. The soilslab can provide envelopes for this purpose.A two week wait from the time you send thesamples to the lab until you receive theresults is typical so send in the samples afew weeks before you intend to fertilize.

A $40 investment in soil testing can savehundreds of dollars in fertilizer or pesticidesduring the year. The test results should pro-vide soil pH, soil type, organic matter con-tent, and levels of all major and minornutrients. An additional test that providesthe sports turf manager with valuable in-formation is a percolation test. This test ratesthe soil on how well water drains throughit. Most soils labs provide recommendationsfor correcting soil and nutrient deficiencies.By repeating these tests periodically andrecording all fertilizer applications as theyare made, you will have a good handle onturf nutrition.

These tests help you select the rightamounts and combinations of nitrogen (N),phosphorus (P) and potassium (I<) and othernutrients for your fertilizer program.However, it is up to the sports turf managerto select from a wide variety of sources foreach of these nutrients. He can purchaseeach of the primary nutrients separately orbuy "complete" fertilizers that have beenpremixed or formulated to contain nitrogen,phosphorus and potassium. Dry, premixedfertilizers are less expensive than formu-lated products. The dry components arecarefully mixed together by the manufac-turer, but the individual components maynot remain perfectly mixed when appliedwith rotary spreaders. The heavier particlesin these fertilizers can be thrown farther thanthe lighter particles by the spreadingmechanism.

Manufacturers also formulate fertilizersto combine all the nutrients onto particlesof a "carrier," such as ground corn cobs,clay or perlite. This eliminates inconsisten-cies when the products are applied and pro-vides the same proportion of nutrients evenlyto the turf. Both mixed and formulated dryfertilizers should be watered into the soilsoon after application.

Gravity feed drop spreader.

Traffic Areas

Ground·driven boom sprayer.

continued on page 28

October, 1987 25

Sports Turf Nutritioncontinued from page 25

Application uniformity is also high whenfertilizers are applied as liquids. Nutrientsthat are in liquid form, soluble in water orthat can be suspended in water are avail-able. As long as these materials are com-patible with others in the same tank, theyprovide very even distribution to the turf area.

In all cases, spreaders and sprayersshould be checked and recalibrated beforeapplying fertilizers to make sure distribu-tion of the granules or sprays is equal acrossthe width of the swath. One method of avoid-ing potential problems with gaps or over-laps is to apply a half rate of the materialin two directions. A colorant can be addedto liquid fertilizers for visible proof of skipsand overlapping. Use the same spreaderor sprayer to apply fertilizers to an impor-tant turf area to avoid inconsistencies causedby differences in the equipment.

Fertilizers, whether they are mixed or for-mulated, complete or incomplete, liquid ordry may contain a wide variety of nutrientsources. The sports turf manager needs toknow how these different nutrient sourceswill affect his turf.

The most important component is nitro-gen. Each nitrogen source has its own burnpotential and rate at which it releases nitro-gen. Commercially produced organic fer-tilizers, such as CompGro and Milorganite,contain a low percentage of nitrogen andrelease it slowly as they break down. Theirburn potential is extremely low. However,it takes larger amounts of these productsto provide the same amount of nitrogen asother sources.

Urea, ammonium sulfate, ammonium ni-trate and potassium nitrate are synthetic(man-made) sources of nitrogen. They arealso the most economical sources of nitro-gen for turf. However, these synthetics con-tain much greater percentages of nitrogenthan organic sources, release it much fasterand have higher burn potentials. The sportsturf manager should check his applicationequipment and rates carefully when usingthese products.

These quick-release fertilizers can becompared to sugar. Sugar breaks downquickly in water and provides the personwho consumes it with a short burst of energy.Quick-release fertilizers give turf a fast burstof growth and color and last just a few days.They provide no long term benefit to theplant.

Chemists developed two basic ways toslow down the release rate of synthetic nitro-gen fertilizers. The first was to chemicallybond nitrogen to other elements througha reaction process. Ureaformaldehyde (Nitro-form) and isobutylidene diurea (ISOU, Par-Ex) are synthetic fertilizers that release nitro-gen over many weeks. Even though theycontain a relatively high percentage of nitro-gen, their slow release rate gives them avery low burn potential.

Ureaform is really a group of compoundscreated simultaneously by reacting urea withformaldehyde under controlled conditions.These products release nitrogen as mi-crobes in the soil break them down. Changesin microorganism activity will alter the rateof release. Low soil temperature reducesmicrobial activity and slows the release ofnitrogen.

50 6.5 70INEUTRAL

95 pH 100

The availability of fertilizer nutrients In the soil can be changed by soli pH. Chart courtesy: AmericanSociety of Agronomy.

28 sportsTURF

By changing the conditions under whichurea and formaldehyde are reacted, slightlydifferent fertilizers are produced. A num-ber of these are categorized as methylolureas or methylene ureas. These slow-release fertilizers also contain a certain por-tion or their nitrogen in the form of urea.

ISOU is created by reacting urea withisobutyraldehyde. Water in the soil slowlydecomposes the IBOU releasing the ureacontained in it. The two things that influencethe rate of breakdown of ISOU are the sizeof the particle and the amount of moisturein the soil. Small particles break down faster.Nitrogen release will be slowed by dry soils.

Sloto-release fertilizercan be applied less

frequently while stillproviding the turf

with sufficientnutrients.

The second method of slowing down thenitrogen release rate of synthetic fertilizersis by coating them. The most economicalmethod of coating to date involves sulfur.Through a process that coats urea dropletswith widely varying thicknesses of sulfur,fertilizer manufacturers are able to controlthe amount of nitrogen escaping throughcracks and imperfections in the coating. Ittakes weeks for all the nitrogen to escapefrom sulfur coated urea. Lesco Inc., Scotts,and CIL have SCU plants.

A more expensive coating process uti-lizes plastic. The advantage of a plastic coat-ing is a more predictable rate of releasethrough precise pores in the plastic. Thecoating can also be much thinner and con-tain a number of different quick-release fer-tilizers, including urea, ammonium nitrateand ammonium phosphate. The rate of nitro-gen release from plastic coated fertilizersincreases with temperature. Manufacturersare continuing their research on plastic-coated fertilizers in orderto produce a lowcost version in the near future. Sierra Chem-ical's Osmocote is a plastic coated fertiliz-er. Estech and Scotts also have productsunder development in this category.

Slow release nitrogen sources have threeprimary advantages. The most obvious isthe extended amount of time they releasenitrogen into the soil. Sy utilizing slow-release fertilizers, the turf manager can applyfertilizers less frequently while still provid-ing the necessary nutritional benefits to theturf. Finally, the slow rate of release great-ly reduces the chance of fertilizer burn.

While fertilizers containing slow-releasenitrogen cost more for the amount of nitro-gen delivered, they reduce the risk of fer-tilizer burn and provide a nutrient base for

the turf. Many sports turf managers applyfertilizers that contain half or more of thenitrogen in slow-release form. Supplementalapplications of quick-release nitrogen canbe made to help turf recover from the wearand tear of sports as well as damage frominsects and diseases.

While potassium may be listed third infertilizer analysis ratios, it is second onlyto nitrogen in importance for establishedturf. All parts of the turfgrass plant containpotassium. It is vital for nearly all biologi-cal reactions taking place within the plant.Without adequate levels of potassium, thehealth and recuperative potential of sportsturf is severely reduced.

Potassium is linked to improving the winterhardiness, drought tolerance and diseaseresistance of turf. You could call it the vitaminC of the turfgrass plant. It is essential forproper storage of carbohydrates in turtqrassroots and the overall health of the root sys-tem. Without a healthy root system sportsturf will not provide a reliable, long-lastingsurface.

Due to the utilization of this nutrient bythe turf and its movement through heavilyirrigated, high sand content soils frequentlyfound in sports turf, potassium levels in thesoil need to be replenished regularly. In fact,this may be the element you should watchmost closely in soil testing. Potassium defi-ciency is recognizable as stunted growth,discoloration and rolling of leaf tips and yel-

Every sports turf manager should have a core sampler in their vehicle.

lowing of older leaves. It is not uncommon burn potential about the same as urea.to apply a half pound of potassium for each Monopotassium phosphate has a very lowpound of nitrogen. burn potential but is priced higher than all

The two primary sources of potassium in other potassium sources.fertilizer are potassium chloride and potas- Phosphorus is important to young turf andsium sulfate. Some caution is advised when overseeded turf areas. It contributes tomaking separate applications of potassium proper root development in seedlings as wellchloride since it has approximately the same as the overall growth of the turfgrass plant.burn potential as urea. Potassium sulfate It is important to turf like the calcium in milkhas a lower burn potential and also provides is important in the diet of newborns and chil-a slight acidifying effect on alkaline soils. dren. Seedlings in a phosphorus deficientIts use on problem acid soils is not advised. soil will have a red cast instead of bright

Potassium nitrate is more expensive than green.the previous two products and also has a continued on page 30

Lely has manufacturedthe most accepted TurfBroadcaster for manyyears. LeIy now offers themost ideal FairwayThatching Implement onthe market.

LELY THATCHER

Model 450 & 600

Specifications2-Models20' Thatcher10' Thatcher7' Transport-20'

10' Transport-IO'5 Position Tine Adj.

Up to 12 MPHWorking speed

3 pt. HitchHydraulic Lift-20'

Features• Thatching grass• Stands Grass up for better mowing• Knocks down mounds of dirt• Improves Fertilizer Penetration• Ideal over seed after thatching• 7' Transport on 20' Model (hydraulic)• Removes Weeds• Working speed up to 12 mph• 5 position tine adjustment• 3 pt. hitch

LELY PACIFIC, INC.P.o. BOX 961

ALBANY, OREGON 97321(503) 926-7753

Circle 120 on Postaqe Free Card October, 1987 29

Sports Turf Nutritioncontinued from page 29

Phosphorus does not move through soilsas rapidly as nitrogen or potassium.However, much of it is tied up chemicallyin the soil, especially in soils outside a pHrange of 5.5 to 7.5. By correcting soil acidityor alkalinity, existing phosphorus in the soilwill become available. Minerals and organicmatter in the soil also provide a naturalsourse of phosphorus but at a very slow rate.For these reasons, soil tests are designedto measure orthophoshpate, the form ofphosphorus. most readily available to theplant.

Most phosphorus sou rces have a rela-tively low burn potential and can be appliedseparately with relative safety. Super-phosphates are the most commonly appliedsource of phosphorus for dry applications.The amount of available phosphorus rangesfrom 20 percent to 50 percent for triple su-perphosphate. Monoammoinium phosphateand diammonium phosphate are frequentlyused for liquid fertilization. Monoammoni-urn phosphosphate is recommended for useon alkaline soils. Excessive applications ofphosphorus, especially on alkaline soils,should be avoided when possible since theycan tie up iron and make this importantmicronutrient unavailable to the turfgrassplant.

Iron is the micronutri.ent of chief concernto sports turf managers. Sandy soils, alka-

Iron deficiencies cansometimes be solvedby correcting alkalinesoil conditions or byimproving drainage.line soils and waterlogged soils frequentlylack sufficient levels of iron. Turf has a sicklyyellow appearance termed chlorosis whenlevels of iron are inadequate. Turf specialistsrecommend application of chelated iron tocorrect deficiencies. This iron source is lesslikely to cause injury to turf than salt formssuch as iron sulfate and ferrous ammoni-um sulfate and remains available to turf fora longer period of time. They are, however,more expensive.

Iron deficiencies can sometimes be solvedby applying sulfur to correct akaline soil con-ditions or by improving drainage. Excessiveapplications of iron can turn turf almostblack. However, light applications are be-ing used by some sports turf managers toachieve a darker green shade for turf withoutusing additional nitrogen. In severe cases,applications of iron may be needed everyfew weeks until the problem is corrected.

Sulfur is also deficient in many soils. Itis a vital component of many plant reactionsas well as an acidifying agent. In additionto elemental sulfur, many fertilizers containcertain amounts of sulfur, including ammo-nium sulfate, potassium sulfate, super-phosphate and sulfur-coated urea.

Ocassionally calcium, copper, magnesi-um, manganese, and molybdenum are lack-ing in sandy soils in certain parts of the coun-try. Calcium and magnesium deficienciescan be corrected with dolomitic limestone.Many complete fertilizers contain smallquantities of these micronutrients. Foliar-applied sources are also available for rapidcorrection of micronutrient deficiencies.

Due to the extensive use of sports turf,it has a higher nutrition requirement thanutility or lawn turf. Bentgrass and ber-mudagrass used for sports require the mostnitrogen during the growing season. Bent-grass fairways need almost a pound of ac-tual nitrogen per 1,000 square feet permonth during the growing season whilegreens often receive more. Bermudagrassgreens also receive a pound or more of nitro-gen per month. Hybrid bermudagrass fair-ways or sports fields need between 1/2 and3/4 pound of nitrogen per month. Commonbermudagrass on fairways and fields re-quires half as much as nitrogen as hybridbermudagrass. Nitrogen rates may need tobe adjusted upward for sand-based root

continued on page 32

30 sportsTURF Circle 129 on Postage Free Card

Sports Turf Nutritioncontinued from page 30

zones and according to the amount of playon the turf.

Kentucky bluegrass requires more nitro-gen than perennial ryegrass, tall fescue, St.Augustinegrass or zoysiagrass. Kentuckybluegrass on high use fields and fairwaysmay need as much as a pound or more permonth, while the other turfgrasses performwell on between half and one pound permonth. Annual bluegrass also does well onsoils with moderate to high fertility.

Maintenance programs with low fertiliz-er budgets can possibly get by with ba-hiagrass, centipedegrass, red fescue andpossibly tall fescue. The newer, turf-typetall fescues however, require more nitrogenthan the forage types such as Alta and K-31.

The higher the sand content of the rootzone the more frequently fertilizers will needto be applied. A high portion of fertilizer ap-plied to sandy root zones should be slow-release.

The manager of a cool-season turf sportsfield on a tight budget should make everyeffort to apply no less than three poundsof nitrogen per year. This can be dividedinto three applications, the most importantbeing in the fall at the end of the footballseason. Applications in spring and late sum-mer should also be made.

Golf course superintendents in the Northshould add a fourth application of fertilizer

in the early spring for fairways of Kentuckybluegrass and/or perennial ryegrass. Bent-grass fairways would possibly require a fifthapplication. Monthly fertilization is advisedfor bentgrass greens during the playingseason.

Managers of athletic fields of commonbermudagrass, centipedegrass or ba-hiagrass should fertilize no less than twiceper year and preferably three times. If theturf is hybrid bermudagrass, try to make fourapplications, but avoid late winter or earlyspring. If the bermudagrass is overseed-ed in the fall, do not fertilize for a monthprior to overseeding. You want to slow thebermuda down so it will not compete withthe annual or perennial ryegrass.

Golf course superintendents with hybridbermudagrass fairways and greens shouldbe on a monthly program from late springto a month prior to overseeding. The fer-tilization program then continues for theryegrass. Southern superintendents withbentgrass greens need to be extremely cau-tious about fertilizing these greens duringthe summer and follow a preventative dis-ease control program.

With the extremely high use of golfcourses and sports fields today, fertilizerrequirements are increasing. There is nosuch thing as permanent, low-fertility sportsturf. Poorly-fed turf will require annual reno-vation at a cost much higher than a properlyscheduled fertilizer program. Fortunately,

IS YOUR FIELD A"WINNER"?

CALL1-800-624-6706

For Details

there are excellent slow-release fertilizerswhich help reduce the number of fertilizerapplications. They will reduce the labor toapply fertilizers, but not the cost of the fer-tilizers themselves.

In a way, fertilization is like irrigation. Youmust first make a commitment to quality turf-grass. Once that commitment is made it hasto be followed up with continuing main-tenance and support. You paid for the hard-ware, now you have to pay for the waterand keep the system performing at itsdesigned capacity.

Realistically, to provide quality sports turfyou must make a commitment to quality turf-grasses which have moderately high fer-tility requirements. To invest in quality sodor seed and then deny the turf the nutrientsit needs to withstand sports is a completewaste. Fertilizer is not an area for budgetcuts. If you have to cut the fertilizer budg-et, you might as well write off the field orfairway.

Finally, the home lawn expert does notunderstand the additional fertilizer require-ments of sports turf. Utility and lawn turfhave entirely different needs. Sports turfmust be kept on a much more sophisticat-ed diet than utility and lawn turf. That diethas been standard on golf courses for years,but lacking on sports fields. There is littledifference between the two as far as thenutrient needs of the turf if it is to providea permanent cover under heavy use. 4.'

gmcuDiJecff}1bzdBLUEGRASS SOD

NEWSTRIPE can supply the products to make your sportssurfaces the most attractive in your conference. Our linemarkers and stencils are being used by major universities,school districts and soccer clubs for field maintenance.

Check these possibilities:• Football • Basketball• Soccer • Playgrounds• LaCrosse • Shuffleboard• Baseball

nMSfAII'\5:::::c =Inc=. ====cP.O. Box 440881

Aurora, CO 80044

32 sportsTURF Circle 115 on Postage Free Card

THE BLEND-Combination of 5disease resistant cultivars chosenon the basis of adaptability to avariety of growing conditions.

SOIL TYPE-820 irrigated acres ofsandy loam mineral soil.

ROOTING-Rapid establishment inany soil type with less water.

Now Available

DuPont PenncrossTURF CREEPING BENT SOD

BLANKETS 75% Sand Base

[II]HUBER RAIICRSOD IIURSERY_Schneider, IN 219/552-0552

• IN 800-553-0552• IL 800-553-0554

Quality Supplier ofSeed, Fertilizer,Chemicals, andEquipment.

Circle 116 on Postage Free Card