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Composting and Compost Utilization Andy Bary WSU Puyallup Oct 3, 2002.

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Presentation on theme: "Composting and Compost Utilization Andy Bary WSU Puyallup Oct 3, 2002."— Presentation transcript:

1 Composting and Compost Utilization Andy Bary WSU Puyallup Oct 3, 2002

2 Composting Decomposition of organic materials by aerobic microorganisms under controlled conditions

3 1.Compost good soil conditioner 2.Improved manure handling 3.Improved land application 4.Lower risk of pollution 5.Pathogen destruction 6.Nutrient management 7.Disease suppression 8.Saleable product??? 9.Tipping fees Why compost

4 Compost Draw backs 1.Time and money 2.Lack of equipment 3.Land 4.Odor 5.Weather 6.Materials 7.N loss 8.Farm operation

5 Analyze Markets Acquire Feedstocks Prepare Material sort, grind, chip, mix, shred Bulking Agents Amendments Determine Recipe Active Composting Low Tech High Tech Curing Time Screening Compost Quality Assessment “overs” Product Refinement & Marketing Blending Additives Bagging Storage Composting Process Flow Chart Adapted with permission from the On-Farm Composting Handbook.

6 Factors that affect composting Oxygen C:N ratio Moisture Porosity, structure, particle size pH Temperature Time

7 Preferred ranges C:N ratio 20-40:1 25-30:1 H 2 O content 40-65% 50-60% O 2 >5% >5% Particle size 1/8-1/2in.varies pH 5.5-6.5 6.5-8.0 Temperature 110-150F 130-140 Reasonable ranges

8 Carbon:Nitrogen Ratio Compost15-25:1 Grass clippings15:1 Biosolids5:1 Food wastes15:1 Dairy manure20:1 Leaves and foliage60:1 Straw80:1 Bark115:1 Paper170:1 Wood or sawdust500:1


10 Composting methods In vessel Aerated static pile Passively aerated systems windrow bunker



13 Composting methods In vessel Aerated static pile Passively aerated systems windrow bunker


15 Composting methods In vessel Aerated static pile Passively aerated systems windrow bunker







22 What can I compost? Animal manures Straw, hay Vegetable matter Yard debris Wood shaving/chips Newspaper Fruit and vegetable wastes Fish processing wastes

23 Organic Production Manures 1.Raw manure OK if crop is not for human consumption 2.Incorporated >120 days before harvest if edible is in direct contact with soil or soil particles 3.Incorporated >90 days before harvest if edible is not direct contact with soil or soil particles

24 Organic Production Compost non animal materials Plant residues, etc No specific composting regulations

25 Organic Production Compost animal materials 1.Initial C:N 25:1 – 40:1 2.Meet PFRP 3.In vessel or covered 131-170 o F, 3 days, All portion of pile meets this temperature. 4.Turned windrow 131-170 o F, minimum 15 days with 5 turns.

26 Soil fertility and nutrient management

27 Nutrient Management Meet crop nutrient needs Maintain soil quality Conserve resources Protect water quality -- reduce leaching and runoff risk

28 Plant Nutrients Major Nutrients Nitrogen Phosphorus Potassium Calcium Magnesium Sulfur Micronutrients Boron Iron Manganese Zinc Copper Chloride Molybdenum

29 How nutrients become available Mineral Matter Organic Matter K Mg Ca N S P K + NH 4 + Ca ++ SO4 -- soluble, available Not available - - -- - - - - - -- Ca ++ K+K+ clay OM - - - - - - Mg ++ K+K+

30 Nutrient Anion Availability AnionBindingSolubility PO 4 -3 stronglow BO 3 -3 mediummedium SO 4 -2 v. weakhigh NO 3 - v. weakv. high

31 Organic N NH 4 + NO 3 - LeachingGases Plants, Microbes Plant residues, Manure Nitrogen Cycle

32 Organic Materials Little or no processing Low nutrient content Slow release of nutrients Plant, animal, or mineral sources

33 Processed Manures Heated >150 o F for 1 hour and less than 12% moisture

34 Organic Materials: Slow release nutrients Plants can only take up nutrients that are in available form (simple, soluble ions). Most nutrients in organic materials are in complex organic molecules or minerals, and are not immediately available to plants.

35 Slow release nutrients Biological processes slowly release the nutrients in organic amendment into available forms. Rate of nutrient release depends on the nature of the amendment and environmental conditions.

36 Nutrient uptake The forms of nutrients taken up by plants are the same for all types of fertilizer -- manufactured or organic.

37 Organic materials: Fertilizers vs. Soil amendments Fertilizer 1. High nutrient content and availability. 2. Main benefit is nutrients. 3. Relatively small amounts applied. Soil amendment 1. Low nutrient content and availability. 2. Main benefit is organic matter. 3. Large amounts applied.

38 Carbon:Nitrogen ratio Low C:N supplies N to plants High C:N ties up N by biological immobilization

39 C:N ratio and N availability C:N <10:1 10:1 to 20:1 20:1 to 30:1 >30:1 N availability High Med - Low Very Low Negative

40 High N Content C:N < 10:1 Rapid N availability Use as a fertilizer Over application leads to excess nutrient levels in soil -- potentially harming crop and water quality.

41 High N Content Examples Poultry manure Packaged organic fertilizers Fresh dairy or goat manure

42 Moderate N Content C:N 12:1 to 25:1 Slow N availability Can add large amounts without risk of over-fertilization Use as a soil amendment Expect some N immobilization (tie-up) shortly after application.

43 Moderate N Content Examples Compost Yard debris Cover crop residues Dairy solids

44 Low N content C:N > 30:1 N immobilization Need to add N along with organic amendment Use as mulch or bulking agent for compost

45 Low N content Examples Straw Sawdust Paper waste


47 Happy Composting

48 Clopyralid in Compost What’s the story? N Cl COOH

49 Clopyralid What is it?  A herbicide that kills many broad-leaved weeds.  It is used on lawns, hay crops, wheat, and some other crops  Legumes, nightshades, and composites are the most susceptible families.

50 Clopyralid How does it get into compost?  Applied to lawns by lawn care companies  Clippings recycled as yard debris become feedstock for compost.  Breakdown of clopyralid in compost is slow.

51 Clopyralid Other sources of contamination  Manure from horses fed grass hay treated with clopyralid  Straw from grain crops treated with clopyralid

52 Clopyralid Will contaminated compost kill my plants?  No. But, there may be symptoms of damage on some susceptible garden plants, such as peas, beans, potatoes, and tomatoes. Most plants are unaffected by clopyralid.

53 Peas, beans and marigolds grown in 3:1 v/v compost:perlite mix Peas and beans show symptoms, marigolds show no symptoms.

54 Leaf from tomato plant grown in unamended soil. Leaf from tomato plant grown in soil amended with 50% compost.

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