1 / 26

What is Compost? Composting Biology and Core Principals

What is Compost? Composting Biology and Core Principals. David M. Crohn Department of Soil and Environmental Sciences University of California, Riverside. Compost: definition.

jin
Download Presentation

What is Compost? Composting Biology and Core Principals

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. What is Compost?Composting Biology and Core Principals David M. CrohnDepartment of Soil and Environmental SciencesUniversity of California, Riverside

  2. Compost: definition • “An accumulation of decaying or decayed organic matter, as from leaves and manure, used to improve soil structure and to provide nutrients.” • Decay is a biological process (not a chemical process) • Properties determine what is a compost (not the production method)

  3. Not all composts are created equal. • Backyard Composting • Vermicomposting • Lasagna Composting • Thermophilic Composting

  4. Thermophilic composting

  5. Actinomycetes Bacteria Fungi Compost microorganisms Illustrations: www.Digitalseed.com

  6. Aerobic processes Microbes, Carbon, & Oxygen Carbon Dioxide, Water, Compost, &Heat

  7. Thermophilic composting • Microbes tend to specialize in the temperatures they prefer. • In California soils and in our bodies mesophiles are most abundant. Pathogens are mesophiles. • Between 110°F and 155°F, thermophiles dominate. • Above about 160°F dieoff begins. • Reliable pathogen kill occurs above 131°F. • Heat greatly accelerates microbial efficiency.

  8. 25x Thermophilic composting • Microbial efficiency approximately doubles for every 18°F increase in temperature • So how much faster will organic matter decompose if it heats from a shady 72°F to a toasty 150°F ?

  9. Active Composting Why compost? • To eliminate disease organisms Animal ● Plant ● Human • To produce a stable and safe soil amendment Nutrients ● Odors ● Phytotoxins Curing

  10. Carbon • Source of energy for microbes • Not all forms are equally available • lignin (less available) • cellulose • fats, waxes, proteins • sugars (more available) C

  11. C

  12. Nitrogen • Vital nutrient for microbes • Needed for protein synthesis • Excess may volatilize as ammonia (NH3) • Other nitrogenous compounds can be odiferous • Also important for plants • C:N ratio • initially about 35:1 • about 10:1 to 20:1 in cured product N

  13. N

  14. Oxygen • Acts as an electron acceptor • Permits efficient liberation of energy from carbon • Energy is used by microbes to grow and reproduce O2

  15. Heat O2 O2 Oxygen: turned windrow

  16. Composting alternatives Turned Windrow In-vessel Static pile Illustration: Rynk et al. 1992

  17. Water • Clings to compost particles • The bath within which microbes grow • Too much fills pores • Oxygen moves slowly into water H2O

  18. Air Water Anaerobic Zone Unavailable Zone Aerobic Zone Compost particle environment

  19. Particle Size Porosity C:N ratio H2O O2 Management parameters

  20. Conclusions • The composter’s success in managing the process will determine • Product quality • Product consistency • Consistent quality increases demand for composts • Increased demand increases product value

  21. Questions?

  22. Mulches, Soil Amendments and Organic Fertilizers David M. CrohnDepartment of Soil and Environmental SciencesUniversity of California, Riverside

  23. Mulches: cover the soil • Protect soils against erosion • Conserve water by slowing evaporation • Control weeds • Control certain plant diseases • Decorate landscapes

  24. Soil amendments: modify soil properties • Improve tilth • Improve water holding capacity • Improve aeration • Improve infiltration capacity • Adjust pH • Promote microbial activity and diversity

  25. Organic fertilizers: slow release sources of • Nitrogen • Phosphorus • Potassium • Micronutrients

  26. Conclusions • Mulches, soil amendments and organic fertilizers are uses, not products. • Composts may serve any of these. • Different composts have different properties, and some will therefore be more suitable for certain uses than for others.

More Related