21What can I compost? Animal manures Straw, hay Vegetable matter Yard debrisWood shaving/chipsNewspaperFruit and vegetable wastesFish processing wastes
22Organic Production Manures Raw manure OK if crop is not for human consumptionIncorporated >120 days before harvest if edible is in direct contact with soil or soil particlesIncorporated >90 days before harvest if edible is not direct contact with soil or soil particles
23Organic Production Compost non animal materials Plant residues, etcNo specific composting regulations
24Organic Production Compost animal materials Initial C:N 25:1 – 40:1Meet PFRPIn vessel or covered oF, 3 days, All portion of pile meets this temperature.Turned windrow oF, minimum 15 days with 5 turns.
31Organic Materials Little or no processing Low nutrient content Slow release of nutrientsPlant, animal, or mineral sources
32Heated >150oF for 1 hour and less than 12% moisture Processed ManuresHeated >150oF for 1 hour and less than 12% moisture
33Organic 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.
34Slow 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.
35Nutrient uptakeThe forms of nutrients taken up by plants are the same for all types of fertilizer -- manufactured or organic.
36Organic materials: Fertilizers vs. Soil amendments Fertilizer 1. High nutrient content and availability Main benefit is nutrients. 3. Relatively small amounts applied.Soil amendment 1. Low nutrient content and availability Main benefit is organic matter Large amounts applied.
37Carbon:Nitrogen ratio Low C:N supplies N to plantsHigh C:N ties up N by biological immobilization
38C:N ratio and N availability <10:110:1 to 20:120:1 to 30:1>30:1N availabilityHighMed - LowVery LowNegative
39High N Content C:N < 10:1 Rapid N availabilityUse as a fertilizerOver application leads to excess nutrient levels in soil -- potentially harming crop and water quality.
40High N Content Examples Poultry manurePackaged organic fertilizersFresh dairy or goat manure
41Moderate N Content C:N 12:1 to 25:1 Slow N availabilityCan add large amounts without risk of over-fertilizationUse as a soil amendmentExpect some N immobilization (tie-up) shortly after application.
42Moderate N Content Examples CompostYard debrisCover crop residuesDairy solids
43Low N content C:N > 30:1 N immobilization Need to add N along with organic amendmentUse as mulch or bulking agent for compost
48Clopyralid What is it? A herbicide that kills many broad-leaved weeds. It is used on lawns, hay crops, wheat, and some other cropsLegumes, nightshades, and composites are the most susceptible families.
49Clopyralid How does it get into compost? Applied to lawns by lawn care companiesClippings recycled as yard debris become feedstock for compost.Breakdown of clopyralid in compost is slow.
50Clopyralid Other sources of contamination Manure from horses fed grass hay treated with clopyralidStraw from grain crops treated with clopyralid
51Clopyralid 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.
52Peas, beans andmarigolds grown in 3:1 v/vcompost:perlite mixPeas and beansshow symptoms, marigoldsshow no symptoms.
53Leaf from tomato plantgrown inunamended soil.Leaf from tomatoplant grown in soilamended with50% compost.