In summary it must be emphasizedthat materials to directly alter the pHshould never be applied unless a pHdetermination has been made. Further-more the pH should seldom be aconcemfor the turf manager. If it becomes ex-cessively high (over pH 7.8) then bealerted to the possible requirement for ahigher phosphorus test to satisfy the re-quirements of the grass. If the pH fallsbelow 5.5 be prepared to apply somelimestone during coring. Inbetween en-joy a good night's sleep.

Composting for~~~....",mnm~

Athletic FieldsMichael J. BladonGrounds Dept., Univ. of Guelph

Benefits ofComposting

The principal benefit of compo stingis to recover or recycle biodegrad-

able materials from agricultural,industrial and municipal waste streamsin an environmentally acceptable man-ner to produce a useful, marketableproduct.

A second benefit is that the end prod-uct (compost) is a safe material whichmay easily be transported using regularcommercial vehicles. The resulting ma-terial has many advantages and can beused in many ways.

For example, there is now evidencethat compost can be used to suppressplant diseases, stabilize soil pH and im-pede the movement and uptake by plantsof toxic metals such as cadmium andlead.

Furthermore, reclamation of stripmines, mine tailings and the rejuvena-tion of salt-damaged soil along road-ways may be aided. In addition,compost recycles the plant nutrients soless fertilizer is needed.

Finally, the use of compost on sportsfields for topdressing, construction orrenovation instead of peat moss is im-portant in two ways. It will help to pre-serve wetlands from which peat isharvested. Generally this harvest is airreversible process with the destructionof the wetlands. The destruction of wet-lands is now a serious environmentalissue, especially among the wildlifepeople.

Peat moss is very expensive - compostis a much more reasonable economicalternative, in fact some landscape ar-chitects are including compost in theirspecifications. In a survey conducted bythe lawn and landscape industry, therespondents categorized themselves as:• 71.3% being generators of lawn waste

(clippings, leaves, branches,

• 34.8% being collectors of lawn waste,and

• 33.0% being composters of lawnwaste.

Of those contractors that were sur-veyed who collected waste and gener-ated compost, 66% indicated they use itthemselves, 26.3% gave the materialaway, and 7.3% sold the compost.

Getting StartedFirst of all, depending on where you

live, obtain a copy of the ProvincialGovernment Guidelines for aerobiccomposting. It will be apparent fromreading these guidelines that in order togenerate good compost you need a rec-ipe which includes: air, moisture, cor-rect C:N ratio, temperature and pHbalance. Finally you will need at leastan acre of land for every 1,000 tonnes ofyard waste.Air: The bacteria which break downorganic matter are called aerobic be-cause they need oxygen. Lack ofaeration, because the pile is too wet,packed to tight, or is too large, can causeit to become anaerobic which can createodours objectionable to neighbours.Furthermore, anaerobic compostingdoes not create sufficient heat (min. of550 C) to kill weed seeds and variouspathogens. So turning, and hence aerat-ing, the pile during the compostingprocess will provide the oxygen neces-sary for the aerobic bacteria.

Moist, Not Wet: If the pile becomes toodry, bacterial production is inhibited andthe composting process is slowed. Fortyto 60 percent moisture is recommended.The material should be damp to thetouch but you should be able to squeezeonly a drop or two of moisture from ahandful. Adding water is easy, however,the extraction of it is impractical. Theaddition of dry leaves, sawdust, newspa-per, or simply turning, will help to dry awet pile.Temperature: If all of the above hasbeen accomplished then the pile shouldheat naturally to at least 55° C, allowingdecomposition in the shortest period oftime. With open piles a minimum of tendays at this temperature is-needed; with'in vessel ' (enclosed) operations a mini-mum of 3 days is needed. Below thesetemperatures the decomposition willslow. Most harmful pathogens are de-stroyed and weed seeds are killed at 55°C. The process is self regulating becauseif the temperature rises above 55° Cmany microbes will die and the pile willcool down. It may also be cooled downwater or by turning.Carbon:Nitrogen Ratio: The ideal C:Nratio for composting is 25-35 parts ofcarbon (C) to one part of nitrogen (N),with an average of 30:1. A high C:Nratio will slow the process, due to lackof nitrogen for protein synthesis andbacterial reproduction. A low C:N ratio(less than 20) reduces bacterial repro-duction because of a lack of carbon - theenergy source for the bacteria. At a ratioof 12:1 further bacterial breakdown ofthe material ceases.

The following values may be used as aguide for materials to use to raise orlower the C:N ratio of the pile.

Grass ClippingsLeavesLeaves (Autumn)Wood, SawdustPaperBarkStrawCow Manure·Horse Manure·

19:130-50:150-80:1300-700:1150-200:1100-150:180:120:125:1

"depends on kind and amount of bedding used.

Balancing the pH: pH is very importantbut very difficult to control particularlyonce the composting process has begun.Most lawn and garden wastes will result

Amount of material required for topdressing operations.

for one acrefor 1000 sq. ft.(cubic yards)

Depth(inches)1/4"1/2"3/4"1"2"Area of some sportsfieldsFootballSoccer

0.781.562.343.126.24

3468

102136272

in a neutral pH. High acid pine needlesmay be added to lower the pH, however,they can also inhibit the growth of somebacteria. Lime may be added to raise thepH, but only under extreme conditionsand is seldom required.

Compost as aTopdressing

The first step is to provide a thin uni-form layer over the established turf. Anyof the commercial topdressers will pro-vide a uniform amount directly, to thesurface, which produces less odour andmess. It helps to level the surface of thefield and aids in seed germination.Hence it is a good practice to apply thecompost in conjunction with aerationand seeding. Compost will increase theorganic matter in the soil in addition toproviding greater resilience and lesscompaction. It will also increase thewater holding capacity of the soil., It is a good idea to run the compostthrough a screener to insure a fine mate-rial that will not only filter down throughthe turf to the crown area but also be freeof debris and stones which may injurethe athlete.

acres2.382.35

hectares9594

Future for CompostThere are more than 200 municipal

waste compo sting plants in operation inEurope. In North America, however,they are much fewer. In the UnitedStates there are about 12 that are turningmunicipal waste into compost: most ofthese are small-scale operations. Port-land, Oregon and Fort Lauderdale, Flor-ida, started operations last year' whichwill compost 600 tons of municipal gar-bage per day.

Our landfills are reaching capacity andmany are already refusing manures andyard wastes. In Ontario we will seelarger, more sophisticated operations.The City of Etobicoke produces some '8,600 tonnes of compost per year. Theyrent a tub grinder for two weeks everyyear to process the material. The City ofToronto has a large 'in vessel' (en-closed) operation.

All these operations will be controlledby governments. Composting is new asa commercial venture so the procedures'will be subject to regulations for solidwaste processing and quality. Becauseof regulations, new sites will be difficultto establish. However, shredders, tubgrinders, mixers, screeners will soon be-come standard equipment in our citiesand towns.

The problem then becomes how tomake best use of this material. Certainlydumping it in a landfill site is a waste ofa valuable organic material. Whilemuch of the volume may be used onhome gardens and on sports -fields, itmay be necessary to utilize a large por-tion on agricultural land.(This article is a summary of the addresspresented by Mike Bladon at the 1993Turfgrass Symposium at Guelph.)