Composting. What is Composting? Environmental benefits. Crop production benefits. Sanitation benefits. Outline 3/4/2016

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1 Composting Heartland Wine Conference What is Composting? the controlled biological decomposition of organic materials. primarily by the action of microorganisms and, to a lesser extent, worms and insects. DeAnn Presley, KSU Agronomy, deann@ksu.edu Environmental benefits When food is disposed in a landfill it quickly rots and becomes methane Methane is a potent greenhouse gas with 21 times the global warming potential of carbon dioxide. Landfills are a major source of humanrelated methane in the United States, accounting for more than 20 percent of all methane emissions. Crop production benefits Soil amendment: improves soil health and structure; increasing drought resistance; and reducing the need for supplemental water, fertilizers, and pesticides. Particularly high in secondary and micronutrients Sanitation benefits Food wastes dumped in standard trash cans and dumpsters in the back alley of a home, store or restaurant can attract rodents and insects, as well as generate bad odors. By placing food scraps in a closed, leakproof, durable, and reusable container, frequently picked up, can reduce problems. Outline Backyard vs. windrow composting Parameters we can easily measure ourselves During Done-ness After Where to send samples for nutrient analysis and/or pesticide testing 1

2 Composting is usually done under aerobic conditions. Aerobic (with oxygen) Anaerobic (without oxygen) Most compost piles are at least part anaerobic at least part of the time. OXYGEN HEAT WATER Organic material Minerals (including nutrients) Water Organisms CO 2 Aerobic organisms require oxygen. The primary byproducts of aerobic composting are compost, heat, water, and carbon dioxide. Major Aerobic Composting Factors Porosity Nutrients (C:N) Water Temperature Acidity (ph) Time Porosity 50% free air space to remain aerobic Gases need to enter and exit Need mix of particle sizes Too much water, goes anaerobic To deal with problems: Turn/aerate frequently Mix coarser material, like woodchips Nutrients C:N = Carbon:Nitrogen Ratio Ideal C:N = 30:1 (30 parts carbon to 1 part nitrogen) Range 20:1-40:1 Manure Yard Waste Wood Chips May need to mix several materials to achieve the right C:N ratio Added Water or Rain Trough A trough in the top of pile will allow rain or added water to soak in rather than running off. Or choose to inject water into pile and then mix thoroughly. 2

MESOPHILIC THERMOPHILIC TEMPERATURE 3/4/2016 Estimating Moisture Squeeze test: Dig into the center of your pile and take out a shovelful of material.

3 MESOPHILIC THERMOPHILIC TEMPERATURE 3/4/2016 Estimating Moisture Squeeze test: Dig into the center of your pile and take out a shovelful of material. 50% moisture is just moist enough that tightly squeezing a handful of it barely produces a droplet of moisture. Temperature Optimum range: o F To kill weed seeds To kill pathogens 145 o F - 1 day five turns 131 o F - 3 days five turns Above 150 o F for any length of time is likely to destroy microorganisms necessary for composting. Fresh Air CO 2, H 20 Fresh Air Temperature rules: Organic production Producers using an in-vessel or system must maintain the composting materials at a temperature between 131 F and 170 F for 3 days A thermometer is the most basic necessary tool in composting o F with 3-foot stem recommended Producers using a windrow system must maintain the composting materials at a temperature between 131 F and 170 F for 15 days, during which time, the materials must be turned a minimum of five times." 7 C.F.R (2000) Organic, can t use herbicides, so killing weed seeds crucial A stainless steel, long-stemmed dial thermometer is inserted into the center of the pile at several locations to measure temperature. There are several more sophisticated types Few thermophilic composting organisms survive above this level. Most weed seeds die. Temperature Phases TEMPERATURE (degrees F) Most human and plant 130 pathogens die Very slow decomposition 90 below this this level Psychrophilic less than 40 degrees F 60 Mesophilic degrees F Thermophilic degrees F Summary of expected windrow temperature conditions. I II III TIME The first phase (mesophilic) may last only a few days as the compost heats rapidly. The second phase (thermophilic) is where rapid decomposition occurs over a few weeks to a few months. Mesophilic conditions return during the third cooling and curing phase that may take several months. 3

4 TEMPERATURE 3/4/2016 Effect of turning on temperature TIME Done Odor Color ph Pathogens Heavy metals and chemical contaminants Organic matter content Inert contaminants Maturity/stability Soluble salts. Also C:N, particle size, moisture, bulk density and nutrients. Odors Finished compost should have little odor. Just an earthy smell. No smell of original input materials. An ammonia smell means it s not finished. Rotten, sulfur smell means its too wet. ph Compost will usually have a ph between 6.0 and 8.0. Material outside this range may cause problems for some plants depending on how compost is used. If outside range, use smaller proportion of compost in blend, depending on soil ph and plant needs. Chemical contaminants Know the source of the inputs Laboratory testing is extremely expensive and its impossible to test for everything. Usually $100+ per herbicide of concern. If it is a concern, limit compost proportions. Pesticide contaminants Pesticides are rarely a problem in composts. Most break down before they reach the compost pile or during composting. At the very least, they are greatly diluted. The one thing that should be avoided is any type of herbicide that is used to kill woody plants, as it usually has a longer half li Testing is costly. Primary solution is controlling your feedstocks. Example: Prairie hay ask what herbicides were used. 4

Inert contaminants Trash non-organic plastic, metal, glass, rocks, etc. Often just an aesthetic concern.

Maturity/Stability Solvita is a test kit you can purchase to determine if compost is mature, or to help troubleshoot problems, such as:

(leachable nitrates or high ammonia) Organic acids or contaminants may not have broken down. What can be composted?

5 Inert contaminants Trash non-organic plastic, metal, glass, rocks, etc. Often just an aesthetic concern. May not hurt anything in most uses. Quality compost should have less than 1%. Maturity/Stability Solvita is a test kit you can purchase to determine if compost is mature, or to help troubleshoot problems, such as: May have high C:N ratio. Nitrogen can be tied up due to excess available carbon. May have low C:N ratio. N may not be in organic form. (leachable nitrates or high ammonia) Organic acids or contaminants may not have broken down. What can be composted? Anything that was once alive. Compostable plastics: Won t compost in small backyard piles, but usually ok in large-scale windrows (size matters, need heat) What about food? Dining center food waste being composted at KSU, roughly 40 tons per year. 5

What can you compost? fruit and vegetable trim out-dated bakery goods and doughs dairy products (cheese, yogurt, etc.

cups, and trays biodegradable bags, plates, cups, and packaging meat from plate scraps (works fine in large scale composting, not in backyards) seafood, including shells liquids (beer, milk, soda,

organics. Although these products are degradable, they break down slowly and composting them requires more care and supervision because they can attract animals and insects. https://www.extension.

6 What can you compost? fruit and vegetable trim out-dated bakery goods and doughs dairy products (cheese, yogurt, etc.) coffee grounds and filters tea bags floral waste eggshells paper Continued soiled napkins, tissues, paper towels, and paper wrappers and packaging corrugated boxes (suggest shredding) paper plates, cups, and trays biodegradable bags, plates, cups, and packaging meat from plate scraps (works fine in large scale composting, not in backyards) seafood, including shells liquids (beer, milk, soda, etc.) salad bar leftovers, including dressings What to avoid Anything inorganic, like plastic, glass, or aluminum Some composting facilities prohibit meat, grease, oils and other non-vegetative organics. Although these products are degradable, they break down slowly and composting them requires more care and supervision because they can attract animals and insects. Good and Bad Compost? Compost is usually not either good nor bad just different. Most compost has beneficial uses. Compost quality is related to the intended use. Compost used without consideration of its specific properties can cause problems. Compost use should be adjusted in relation to its specific properties. Unfortunately, for the user, it is often buyer beware. Testing Labs Testing labs KSU Soil Testing does NOT test compost But they can provide contact information for other labs that do Servitech Labs in Dodge City is where I send Woods End Research Laboratory Sell Solvita kits 6

Compost: Quality Considerations. DeAnn Presley, KSU Agronomy, RESEARCH & EXTENSION

Compost: Quality Considerations DeAnn Presley, KSU Agronomy, deann@ksu.edu Outline Parameters we can easily measure ourselves During Done-ness After Where to send samples for nutrient analysis and/or pesticide