SEPTEMBER/OCTOBER 2003

BY Will Brinton and Alan York

“Compost” is a word withancient enough rootsthat its derivation is dif-ficult to trace. The verb

“to compost” comes from componera,Latin for to bring together. By theseaccounts, recycling organic waste andcomposting are closely associated tothe earliest roots of viticulture.

Today, pressure mounts to recycleever-larger amounts of waste in ever-smaller or more densely populatedregions. There is also growing realiza-tion of the senselessness of haulingorganic materials to landfills.

Re-energizing of composting raisesmany questions. These include: Whencomposting was small and sustainable,how did it merge into the naturalrhythms of each farming operation?Just how much technology is requiredto make proper compost? Further,when is compost actually compost?Author Gene Logsdon, writing inBiocycle in 1989, said, “In the not-too-distant future, compost making maywell be as much an artful science aswinemaking.” Indeed, when you con-sider the maturing of plant-growthproperties and the increase of naturaldisease suppressiveness over time incompost, it really can be accuratelycompared to controlled ageing of wine.

With composting now assuming itsrole as a vital agricultural activity, newpressures are mounting that threaten tomarginalize it as an isolated technologicalprocess without any direct roots in farm-ing. An example of the apparent extremesto which modern waste and compostinghave been driven is agriculturalist Dr.Konrad Schliess’s observation after a 10-

year survey on the status of compostingin Switzerland: “From a functional pointof view, it is apparent that the sole pur-pose of modern composting is to processgreen waste with a minimum of outlayand get rid of the end product as quicklyas possible.” (Konrad Schliess 2002-Swiss Agency for Environment, Bern).The analogy of this situation to wine-making would be to go for maximiumgrape yields and complete minimizationof maceration. Composting requiresproper time and management to result ina soil- and crop-improving material.

With organic waste issues arisingeverywhere and recycling increasinglymandated by legislative act, compost-ing has been promoted as an industryunto itself, separated from its originalagricultural roots. Now,under often strictauthority of solid wasteand environmental agen-cies, composters havecome to rely heavily onthe “tipping” fees theycharge agricultural pro-ducers to dispose theirwaste. Composting fac-ilities have thus becomekind of glorified dumps,with the revenues fromthe sale of their end-prod-uct — compost — strictlya secondary concern. Thisis a very curious develop-ment as for farming.

We recall the experience of manyEuropean vineyards in the early daysof large-scale municipal composting inthe 1970s and 1980s. Then, soils in thevineyard became contaminated withnon-biodegradable residues found inthe waste stream, which in turn endedup in compost that was often providedfree of charge to growers.

Certainly, French and Germangrowers have learned from the experi-ence of contaminated mixed-wastecomposts. Our own Woods EndLaboratory (Mt Vernon, ME) analyzescompost not only for nutrients but alsofor specific physical (plastic and glass)content. We use the German limit of0.5% as a maximum acceptable con-tent. In fact, determined to replace the

Broadcast-spreading ofcompost (under 3 tons/acre) at McNab RanchVineyard, Ukiah, CA.

PART I — BASICS OF THE PROCESS

SUSTAINABLE

compostingIN THE VINEYARD

Community compost containing plastic andother non-degradable debris being spread inFrench vineyard. (Photo by Woods EndLaboratory)

concept of waste with that of compost-product, Woods End Laboratory haslaunched a quality ranking system thatuses a matrix of test parameters to clas-sify compost into six best-use groups.This enables growers to properly selectapplications, leading to better results.Compost improperly used can beworse than no compost at all.

Clearly, the pressures for processingorganic wastes, including in somecases, the levying of financial penaltieswhere recovery rates are not attained,does not directly translate into a qual-ity product for agriculture. That goal isactually determined by the bargainingpower of the grower as buyer, plus thecomposter’s ability to utilize the skillsof agricultural and horticultural pro-fessionals to achieve appropriate andrealistic use standards.

The incidence in the past two yearsof herbicide residues being discoveredin composts from commonly used turfchemicals is one example of the chang-ing landscape for compost. While somequickly blamed the agri-chemical com-panies, the essential problem is therapid escalation of broad-based recy-cling in the absence of defined agricul-tural goals — even, we might add —without a sense of any market.

Working with the agricultural goalsof composting, we discovered a lack ofqualified assessment regarding whatlevels of residue were actually harmful,if any. As it turns out, in the case of vine-yards, when we determined the actualpotential for phytotoxicity in bioassays,and then considered the realistic appli-cation rates of the particular compostproduct in the vineyards — the poten-tial risk could be readily managed.(Brinton & Evans, 2002; 2003).

These realities affect both sides ofthe equation: On one hand, growersdesiring to use compost must realizethat available products have not neces-sarily been designed for their particu-lar use, and may meet only minimalenvironmental standards, set by solid-waste laws designed primarily to protectthe consumer and the environment.

On the other hand, a producer whowishes to process waste into compostwill find that all the technology andequipment to do it are readily available.The real need is to re-integrate compost-ing into operations where the organicwastes are produced, thereby restoringcompost’s nature essentially as a prod-uct. The problem is that guidelines andstandards on how to use it are in their

infancy. This ongoing tension betweensheer production and proper use enor-mously intensifies the need for qualitymanagement at all levels.

The returned nutrients and organicmatter have their own value and belongessentially to the vineyard cycle, as wewill show. This means that the value ofthe nutrient and organic matter in thecompost directly offsets expenses thatwould otherwise be incurred. (Forexample, we have found most compostshave $12 to $15/ton of nutrient valuealone, and in organic-BTU value, a formof currency that relates to microbialecology, there is another $15/ton poten-tial.) (Parnes, 1990).

In addition, if you do your owncomposting, tip fees are not a control-ling issue anymore since the potentialcost savings of composting over haul-ing waste to a dumpsite or speciallandfill are obvious.

Finally, governmental rules and regu-lations fall to the side except in the case ofvery large vineyard operations. For exam-ple, in California, to create a vineyardcompost site that will be less than 2,500cu.yds/year, only a grading permit isrequired. These minimal size limits varyby state and by the type of input waste

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Microscopic image of grape seeds whichhave partially survived 1-year compostcycle. (McNab Ranch/Photo by Woods EndLaboratory)

cover

crops

compost

Vine cycle

pomace(stems, seeds, skins)[potential loss]

canes [potential loss]

removal

wine

man

ure

that is being used. What simply remains isto set up composting properly, to fullyunderstand the nature of the materialsand the minimal equipment required,and to possess an adequate concept of thebiology and chemistry of the process inorder to produce a useful product.

Quantities of pomace and other wastes

Grape pomace, the result of press-ing grapes for wine and juice, is anunusual product for which practition-ers and scientists have struggled tofind an effective recycling and dis-posal method. The Italians long agocreated grappa from fermentedpomace. The French distill it for marcbrandy. Creating grappa or brandyreduces the vineyard waste streamstill further — by about another 25%to 30% — so that the final quantitiesdisposed of have traditionally beenmore easily managed in a sustainablefashion within small acreages.

Pomace is rich in nutrients, such aspotassium, calcium and nitrogen.European experience indicates thatpomace, when recycled, contributesback to the soil about 1⁄3 to 1⁄2 of thenutrient and organic matter that thegrape removes in its yields.

Below, we will look at some actualcalculations and laboratory values wehave determined for these nutrient,organic matter, and energy traits ofvineyard wastes. Careful supplemen-tation of pomace, prior to composting,to condition it, ends up largely fillingthe other two-thirds to one-half por-tion of needed organic matter andnutrients, thereby closing the cycle forthe vineyard. Naturally, soil tillageand cover cropping — especially theuse of legumes and other cover cropsin the vineyard, plus the losses thatoccur in leaching and erosion — willsignificantly influence the degree towhich, a relatively balanced nutrientand soil organic matter budget can beattained by composting. The beautywith grapes is that so much of thisconcept, once practiced, can be seenand tasted.

Grape pomace, however, is a veryunusual waste. Owing to its uniquecomposition, especially the high con-tent of lignified tissue in the seeds and

stems, plus the acidic and partiallyfermented nature of pomace, itdecomposes very slowly. Seeds areoften visible months to years afterstockpiling — and even after com-posting.

In a recent compost project atMcNab Ranch (Ukiah, CA), we identi-fied partially decayed grape seeds byoptical microscopy, one year after com-posting was started (see photo images).In fact, having started with about 5%seeds in the initial compost mix, theend compost had more than 12%,resulting from concentration as the restof the organic matter decayed.However, these remaining seeds arecertainly not viable and are, in fact,partly humified. In contrast, if youspread pomace raw, you can count onseeds sprouting within the vineyard.

There’s another potential limitationwith pomace. The low alcohol contentof the pomace residue relegates it bysome state laws, such as in California,to a special landfill category.

Our view is that maintaining ahealthy balance in a vineyard is moreattainable by appropriate recycling viacomposting of pomace and other graperesidues. The value and significance ofthis recycling must be calculated asclosely as possible, since the obviousnutrients and organic content will havean effect, and quality grapes are sensi-tive to over-fertilization. Conductedproperly, the nutrient and humus needsof the vineyard, in concert with tillageand cover cropping patterns, can be sus-tainably managed with a minimum ofadditional external soil inputs.

Test traits of pomace: balancing for composting

Pomace — resulting from pressinggrapes — is essentially a heterogeneous

mixture of seeds, skins, and pulp, and usu-ally also the stalks, depending on whende-stemming occurs. In any event, the ratioof the four elements varies with grapevariety and yield levels. Using Universityof California-Davis and Penaud’s ranges,we calculate that pomace, after pressing,has an average of 8% seeds, 10% stalks/stems, 25% skins, and 57% pulp.

If de-stemming is done prior tocrushing, then a separate pile of stalksresults, which can be mixed back in tocreate compost source material. InEurope, before changes in environmen-tal rules in 1995, many vineyardsburned the stalks (rafle in French).Currently, many are composted. In theLanguedoc-Roussillon region, werecently learned of 40 cellars represent-ing 2,000 growers pooling pomaceafter distilling marc brandy. The resultis 20,000 tons of compost, which isdelivered back to willing growers —and the demand exceeds the supply!

Pomace, as a whole is relatively richin nitrogen, potassium, and calcium.Nitrogen is largely in the seeds andpotassium in the stalks, juice, and pulp.Most estimates rank potassium as themost prevalent nutrient in pomace, fol-lowed closely by calcium and nitrogen;the ratios of the three vary with varietyand yield (Gärtel, 1984; Winkler).These represent the very nutrients wewant to recapture for the vineyard. Theorganic matter content is also obvi-ously very high — this representspotential soil humus to compensate fornatural soil losses. If pomace weredried, the analysis in terms of N-P-K-Cawould be nearly 2-0.5-2-2; arespectable composition.

It is instructive to examine a pomaceanalysis in view of composting (seeTable I). We show a specific test of ageneral pomace mixture from a winery,

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Table I. Laboratory composition of pomace by-product

SAMPLE Water pH C:N Density Salt, Organic Total-N PotashRatio g/cc mmhos Matter

POMACE %dm %dm %dm(merlot mix) 14.7% 6.4 19.5 0.36 1.9 91.6% 2.53% 1.8%Pomace (Range of Values) 12–85% 3.5–6.5 18–27 0.3–0.5 1.0–2.5 90–94% 1.8–2.6% 1.5–3.0%Per ton of wet waste (avg) 1000 lbs – – 25 lbs/ft3 – 910 lbs 25 lbs 20 lbs

compared to a range of values we haveobserved in the laboratory. This stock-piled material possessed somewhatunusual pH of close to neutral. Theranges show what can be expected,however, indicating that testing of pHprior to composting is helpful.

From a compost textbook viewpoint,the C:N ratio of pomace appears ideal forcomposting. But textbook guidelines canbe very misleading, and we rarely usethem. Even with its relatively low C:Nratio, pomace should be thought of moreas a “carbonaceous” waste. This isbecause of its high percentage of lignifiedstructure, ranging from 17% to 35% of thetotal dry weight. The nitrogen, in theform of lignified protein inside the seeds,is highly unavailable. Thus, the custom-ary blending with “carbonaceous mat-ter” would not be in the best interests ofcomposting. Even worse, the porosity ofthe stems component may be so high asto cause excessive drainage and drying.

Another important point is thatpomace typically possesses a very lowpH — depending on the variety, butusually in the range 3.5 to 3.8.Stockpiling pomace in open pilesexposed to air causes a natural driftupwards, but this is hard to predict,since it depends on so many factors:moisture content, size of pile, andamount of air. There can even be post-stockpiling fermentation under wetterconditions with a shift into acetic acidproduction, making the pomace moredifficult to compost. This mostly lowpH of pomace is partly why stockpilingpomace rarely results in compost.Compost microbes require at least a pHof 6.2 to really get started.

If you do not compost, considerthese raw traits and how undesirablethey may be for direct raw landapplication! To go further, and makea product, some simple guidelinesare needed. It is essential to blend inother materials that possess comple-mentary properties. We call this “con-

ditioning.” One rule of thumb is thatthe added ingredients or conditionersmust be rich in available carbon andlow in lignin, and they must possessa proper initial C:N ratio (in therange of 17 to 30).

The C:N ratio is discussed a lot incompost literature, yet, since the C:Nof pomace is quite often satisfactory,you don’t want to be adding any otheringredients that need their own C:Nadjusted! (That’s one reason we don’trecommend wood chips unless youare trying to recycle old barrels.) Weprefer manures that contain amplebedding — enough course material toact as a major (but temporary) struc-tural support for the compost. Thesealso supply pH-modifying factors(such as raising the pH to at least 6.5).Dairy, cattle, and horse manures thathave been blended with straw or hayare preferred.

There are some options that do notinclude substantial quantities of cattlemanure (if unavailable). One approachwould be to shred the stems toimprove particle contact, since nor-mally the pomace cannot be keptmoist from excessive porosity.Shredded landscape-greenwaste couldthen be added at any ratio so long asthe CN of the whole mix remainsbelow 30. We discourage use in vine-yards of carbonaceous compostswhich turn into a sink rather than asource for nutrients. There is a dangerthat use of greenwaste alone will notcorrect the low initial pH of somepomaces, so this must be checkedprior and after mixing.

Considering a nutrient budget,there’s an astonishing discovery thatcomes after balancing the pomace inthis way prior to composting. Assum-ing we are using approximately a50/50 volume mix ratio (pomace:manure), the nutrient concentrationsby analysis are about the same as whatwe started with, but the mass is now

twice as large, due to the addedmanure. Thus, the earlier rule ofthumb (about one-third to half of thevineyard needs being provided for bypomace recycling), is now brought upto a range of two-thirds to nearly100%. That’s nutrient-sensible com-post recycling.

What remains is to adjust the qualityof vine growth with management prac-tices: cover cropping (with its own nutri-ent needs), tillage that partly regulatesthe supply of nitrogen, and pruning,which controls overall vigor. This is onlyto say that nutrients and organic mattercontained in finished pomace-compostare just the start of a well-managed soil-nutrient budget for a vineyard, a budgetthat is frustratingly hard to calculate,since it is not an exact science. The objec-tive is simple sustainability based onsound and conservative use ofresources, backed by careful observa-tions on quality of growth and measure-ments of inputs relative to outputs tovalidate the performance.

A simple scheme for the input sideof a nutrient budget that includes compostwould be as follows (more in Part II):

Compost input (t/a) x nutrient con-tent x availability factors (such as for N-P-K-Ca) = nutrient input + other inputs(compost from previous year x avail-ability factor one-half of previous year)+ (estimated legume input of nitrogen)+ (natural release of soil nutrients) =estimate of total nutrients available.

Composting will not make the nutri-ent budget in a vineyard any simpler; infact it adds factors (such as nitrogenavailability) that are less easily mea-sured and calculated. Nevertheless, theuncertainties are mostly in your favor.

If using cover crops, consider vinedensity; up to two-thirds of a vineyardmay be non-grape crops with their ownnutrient needs. There are also losses suchas from canes and debris that may not berecycled, plus normal weathering andleaching that are difficult to quantify.

What amount of compost works inthe end? As little as 1 ton per acre(TPA) up to 4 or 5 TPA (broadcastapplication) may compensate forthese various needs. If more than that,there should be special nutrient needsor the sheer amount of nutrients maydrive uncontrollable vigor.

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Table II. Laboratory composition of finished pomace/manure compost

SAMPLE Water pH C:N Density Salt, Organic Total-N K CaRatio g/cc mmhos Matter

Finished pomace/manure compost 40.0% 8.3 11.0 0.8 12.0% 42.0% 2.20% 2.6% 2.4%

How to do itWith all the considerations of C:N,

nutrients, and texture for pomace-com-posting, the real work remains to bedone: putting the piles together andphysically managing them. Whereaserrors and alterations in the flow ofmaterials lead to qualitative problems,miscalculations in the area of compostoperations may be very costly — andresult in environmental damage.Examples include: odors from overlylarge piles, leaching in spring rains frompoorly controlled sites, insect problemsrelated to stockpiled pomace andmanure prior to mixing (such as fruitflies and household flies).

The following is a list of essentialprerequisites, starting with the highestpriority:

1) Site layout — Must be adequateto handle the volume of flow and towithstand equipment traffic under themost wet conditions expected.

2) Equipment — Proper selectionof loaders and field spreaders to han-dle input and spreading of materials.

Turning equipment must also be con-sidered for what cannot already be man-aged with #2 above. The authors con-sider special turners to be strictlyoptional.

3) Monitoring tool — Long-stemtemperature probe. Oxygen and CO2sensors are rarely essential to making agood product, but they do provideinformation very interesting to com-post practioners.

One cannot over-emphasize theneed for proper site design, and usu-ally the most basic state regulations forcompost sites recognize this. Manywell-intentioned efforts at compostingare compromised as a result of choos-ing a poor location and a poor soil typeon which to pile the materials.

It is preferable to have an elevated,well-drained location, but paving maynot be necessary. One can use a com-pacted surface similar to a gravel park-ing lot, or a road surface in the vineyardthat possesses adequate side access.

The objective is to be able to pile andmove materials late in the year, andthen again intensively in the spring,prior to final turning and use in a vine-yard. A popular method in Switzerlandand central France is called “field-edge

composting,” with compost windrowslaid out along vineyard and farm-gravel roads, assuring at least one sidehas a solid surface for year-roundaccess.

Growers often ask: “Given a goodsite, what is the ideal means of com-posting?” In a recent compostingstudy we participated in with CornellWaste Management Institute in NewYork state, composters all over thestate had their products tested, andresults related to composting methods.

No distinct advantage emerged forany specific method, whether pas-sive-aerated windrows (PAWS) orintensive windrowing. PAWS com-posting originated in Canada, andrefers to piles being placed over per-forated PVC drainage pipe, allowingair entrance passively into the bottomof the pile. Windrows, in contrast, arelaid out in long rows and turned witha farm-based power turner, such as aPTO-driven compost turner, orloaded into a manure spreader andthrown back into a windrow.

In the New York study, simple fac-tors like moisture content appearedto exert a significant influence onboth nutrient content and the matur-ing process. Moisture, in turn,appeared to control pH, and com-posts had higher, less desirable pHvalues longer if they were main-tained too moist. What was toomoist? This refers to compost beingclose to saturation in water content.As with soils being near field capac-ity, a compost has a certain holdingability dictated largely by how muchorganic matter is present. This makesit hard to state categorically what isideal moisture.

In soils, organic matter plays amuch less significant role in waterholding capacity, where texture ismore important. For compost, theorganic content dictates optimal levelsof moisture, being about 60% at thebeginning, and declining steadily tounder 35% during the compostprocess, depending on age of material.

In the Cornell study, the most sig-nificant factor in compost was thetype of compost-pad design, whichbrings us back to site layout. Of 25compost sites we examined, those

with a lower quality pad (called“unimproved” in the study) wereassociated with lower organic con-tent, lower nutrients, and higherweed seed counts. This suggestscomposts may tend to leach and haveexcessive soil mixed into them whenmade on poorly controlled ground.

Another factor was noted in arelated study conducted by WoodsEnd Laboratory for the U.S. Depart-ment of Agriculture (USDA) technicalcenter in Chester, PA (1995). The studyexamined how differing intensities ofcomposting influence the quality andpathogen content. The astonishingresult: while twice weekly mechanicalturning did decrease the amount oftime to completion, it also significantlyincreased nutrient losses, especiallynitrogen and organic matter.

The advantage to mechanized turn-ing was found in the homogenization ofthe piles, which made the material looka lot better and spread more easily, butthe increased cost of this action has to beweighed against the value for the end-use. For example, twice-weekly mecha-nized turning for 16 weeks cost a total of$41.23/ton, compared to $6.75/ton forthe same manure turned with a bucketloader every two weeks.

We note these facts because it is oftenassumed that composters, especiallyorganic or biodynamic growers, have spe-cific methods or theories for composting.This is not the case and it certainly isn’tnecessary. What we mean here is that, first,compost is thought to require high-tech-nology, which it does not, and second, bio-dynamic growers are thought to be anti-technology, which is not true.

Recent adaptations of compostingmethods include various forms of

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Table III. Desired attributes ininitial compost mix:

1) bulk density, wet weight, 1000 to 1200lbs. per cubic yard

2) pH >6.03) CN ratio between 20 to 30.4) Moisture content not more than 70% of

water holding capacity.5) Temperatures after heat-up in range

130ºF to 140ºF for two weeks, turnedonce, then temperatures may be inoptimal range of 110ºF to 140ºFthereafter.

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agricultural technology, such as bucketloaders and manure spreaders used forturning, but there is no concise or theo-retical basis for these differences inorganic and biodynamic circles.

It is true, however, that biodynamicmethods tend to be low-tech, favoringthe environment of the compost pile overthe mechanical aspect of how it is han-dled. But neither organic nor biody-namic growers are exempt from the basicrules of site layout and proper blendingof initial ingredients. Alot of anxiety con-cerning equipment and quality could beput aside by determined and unbiasedfocus on the basics of the compostingprocess.

Even more recently, the rapid growthof the green waste composting industryhas prompted significant upgrading ofavailable equipment. While in manycases, these developments representcost-saving improvements, the intrinsicbiological process of composting — asour USDA and New York state studiesfor Woods End have shown — remainsessentially unchanged.

If your compost is too wet, no amountof turning is likely to fix it. We considerthe same to be true with regard tomicrobes. You need only establish theproper environment and in most casesthe result will be a diverse, active micro-bial population. We have found that noamount of additional microbes will fix apoor environment, or repair a failedcompost.

However, if one is unable to make aball of compost stick together, the mix-

ture is most likely too dry, which mayalso be confirmed by conspicuous pres-ence of white mold in the compost giv-ing the piles the appearance of “ashing.”

Similarly, with static-aerated compostpiles, a form of mechanical-forced aera-tion that was popularized for sludge bythe USDA in Beltsville, MD in thelate1970s, if the pile is too dense or toowet, we have observed that blowing ofair can result in obvious short-circuiting,where the air takes the path of least resis-tance out of the pile. This can also be aproblem in high-tech compost systemswhere piles are inside bags or in con-trolled, aerated tanks. Thus, it all comesback to choosing proper initial mixes andgetting the texture and moisture condi-tioned correctly at the start. Once theseconditions are correct, then an appropri-ate form of technology, minimizing inter-vention, will be most cost-effective.

SummaryGiven the seasonal realities of vine-

yard management, the rapidity of com-posting is not a critical factor for success.Sound practices are. A six- to 10-monthprocess is likely to prove the safest andmost useful approach. This allows suffi-cient time for stalks and seeds to breakdown and lose viability, with a corre-sponding full stabilization andpathogen-destruction in the compostingmaterial. ■

In Part II, the authors will explorespecifics of obtaining compost and use of com-post in the vineyard for nutrient and diseasecontrol purposes.

William F. Brinton, Ph.D. studied agron-omy and environmental science and isfounder and director of Woods End ResearchLaboratory, Mt. Vernon, Maine with abranch office in Europe.

Alan York, past president of theBiodynamic Agricultural Association, haspracticed horticulture and is an internationalconsultant for wine grape growers.

ReferencesAME (1996) Marc de Raisin-Provoquer

la Demande. [Grape Pomace-ProvokingDemand] La Lettre de L’Environnement enLanguedoc-Roussillon Nr. 14.

Brinton, W. (2002) Compost Quality andManagement Issues, Resource Recycling Vol.6.

Brinton, W. & E. Evans (2002)“Herbicides in Compost — Potential Effectson Plants.” Composting News Vol 11 (2002).

Brinton, W., E. Evans, C. Blewett (2003)“Presence, Degradation and Crop Responseto Low level Residues of Herbicides inCompost.” Amer Soc. Agronomy, NEMeetings, Burlington VT.

Cornell Waste Management Institute(2003) Compost Marketing and LabelingStudy. www.cwmi.edu.

Gärtel, W (1993) Grapes. In NutrientDeficiencies and Toxicities. W. Bennet Ed.,American Phytopathological Society. St.Paul.

Howard, A. H. (1947) The Soil andHealth. Rodale Books, PA.

Ingels, C. (1992) “The Promise ofPomace.” Univ California SAREP Vol 5:1.

Logdson, G. (1989) “A New Sense ofQuality Comes to Compost.” Biocycle, Vol 6-Dec. Emmaus PA.

Parnes, R (1990) Fertile Soil. Ag Access.Davis.

Peynaud, E. (1984) Knowing andMaking Wine. Wiley Interscience.

Rynk, R., ed., (1992) On-Farm Com-posting Handbook. Northeast RegionalAgricultural Engineering Service. Ithaca,NY.

Schliess, K. (2002) Kompost Vermark-tung in der Schweiz [Compost Marketing inSwitzerland] Report to: Swiss Agency forEnvironment (BUWAL), Bern.

WERL (1995) On Farm Composting:Guidelines for useof Dairy and PoultryManures in Composting Formulations.USDA Technical Ctr. Chester Pa (reportavailable from: Woods End Laboratory. MtVernon Maine).

Winkler, A. J., J. A. Cook, W. M. Kliewer,L. A. Lider (1974) General Viticulture, UCCal Press, Berkeley.

Ziegler, B. (1997) Verwertung vonKellereiabfälle [Recycling Wine CellarWastes], SFLA, Neustadt Germany.

How to tell if compost is too wet

To get the moisture correct, we use asimple technique which is called a “FaustProbe” in Germany. A fist-full of compostis taken in the hand and squeezed tightly.If moisture but not free water appearsbetween the fingers, the moisture is ideal;if however, water flows out of the tightlyclenched fist, it is too wet.

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