Composting and Compost Utilization

1. Composting andCompost Utilization Andy Bary WSU Puyallup Oct 3, 2002

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

3. Why compost • Compost good soil conditioner • Improved manure handling • Improved land application • Lower risk of pollution • Pathogen destruction • Nutrient management • Disease suppression • Saleable product??? • Tipping fees

4. Compost Draw backs • Time and money • Lack of equipment • Land • Odor • Weather • Materials • N loss • Farm operation

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

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

7. Reasonable ranges Preferred ranges C:N ratio 20-40:1 25-30:1 H2O content 40-65% 50-60% O2 >5% >5% Particle size 1/8-1/2in. varies pH 5.5-6.5 6.5-8.0 Temperature 110-150F 130-140

8. Carbon:Nitrogen Ratio Compost 15-25:1 Grass clippings 15:1 Biosolids 5:1 Food wastes 15:1 Dairy manure 20:1 Leaves and foliage 60:1 Straw 80:1 Bark 115:1 Paper 170:1 Wood or sawdust 500:1

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 • Raw manure OK if crop is not for human consumption • Incorporated >120 days before harvest if edible is in direct contact with soil or soil particles • 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 • Initial C:N 25:1 – 40:1 • Meet PFRP • In vessel or covered 131-170oF, 3 days, All portion of pile meets this temperature. • Turned windrow 131-170oF, 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. Major Nutrients Nitrogen Phosphorus Potassium Calcium Magnesium Sulfur Micronutrients Boron Iron Manganese Zinc Copper Chloride Molybdenum Plant Nutrients

29. How nutrients become available Mineral Matter Organic Matter N K P Not available Mg Ca S - - K+ NH4+ Ca++ SO4-- soluble, available Mg++ Ca++ K+ - - - - - - - - K+ - - - - - - - clay OM

30. Nutrient Anion Availability Anion Binding Solubility PO4-3 strong low BO3-3 medium medium SO4-2 v. weak high NO3- v. weak v. high

31. Nitrogen Cycle Plant residues, Manure OrganicN NH4+ Plants, Microbes NO3- Leaching Gases

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

33. Processed Manures Heated >150oF 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 • Fertilizer1.High nutrient content and availability. 2. Main benefit is nutrients. 3. Relatively small amounts applied. • Soil amendment1.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 <10:1 10:1 to 20:1 20:1 to 30:1 >30:1 N availability High Med - Low Very Low Negative C:N ratio and N availability

40. High N ContentC: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 ContentExamples • Poultry manure • Packaged organic fertilizers • Fresh dairy or goat manure

42. Moderate N ContentC: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 ContentExamples • Compost • Yard debris • Cover crop residues • Dairy solids

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

45. Low N contentExamples • Straw • Sawdust • Paper waste

47. Happy Composting

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

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.