Composting is a biological process wherein organic raw materials or "feedstocks" are transformed by organism activities into a stabilized soil-like material called compost. Raw materials: Organic matter; Oxygen; Water; Microbes. Heat and CO2 are produced. Finished compost with humic matter results.Since the beginning of agriculture farmers have relied on biological processes for enhancing soil nutrition. With the advent of chemical fertilizers in the early 1900s, many farmers discontinued the use of green manures, crop rotations, and animal manures. Additionally, many farmers only grow one or a few crops, and farmers usually either grow crops or livestock but not both. WSU has conducted extensive research on the use of compost as a soil amendment and source of nutrients. This work points out the need to understand the composition of a particular product (compost are highly variable) and how it acts in a soil, especially in terms of potential nutrient release. As an already-stabilized material, compost may be more useful for improving long-term soil quality and nutrient supply than as an immediate source of nutrients for crops. In addition, composting is used to manage municipal and mixed waste streams, leading to odor and contamination problems, and is being evaluated for its ability to break down organic chemical contaminants (e.g. hormones, antibiotics). Research and extension on these topics is now underway at WSU.

Featured Compost Publications

  • Advancing Organics Management in Washington State: The Waste to Fuels Technology Partnership 2015-2017 Biennium

    Chen, S., Frear, C., Garcia-Pérez, M., Kruger, C., Ewing, T., Jensen, J., Yorgey, G., Gang, D.R., Amonette, J., Ayiania, M., Berim, A., Botella, L., Carbajal Gamarra, F.M., Cleary, J., Dunsmoor, A., Finch, R.W., Fuchs, M., Haghighi Mood, S., Hall, S.A., Han, Y., Jobson, B.T., Long, R., Ma, J., Mainali, K., Moller, D., Neuenschwander, L., Seker, A., Sjoding, D., Stankovikj, F., Suliman, W., Tanzil, A., Terrell, E., Tran, C-C., Xiong, X., Yu, L. 2018. Compiled and edited by Hills, K., Hall, S.A., Saari, B., Zimmerman, T. Waste 2 Resources, Washington State Department of Ecology Publication No. 18-07-010. Olympia, Washington. 424 pp. June 2018.

  • Soil Amendments

    Yorgey, G., W. Pan, R. Awale, S. Machado, A. Bary. 2017. Chapter 7 In Yorgey, G. and C. Kruger, eds. Advances in Dryland Production Systems in the Pacific Northwest. Washington State University Extension, Pullman, WA.

  • Advancing Organics Management in Washington State: The Waste to Fuels Technology Partnership

    Chen, S., C. Frear, M. Garcia-Perez, J. Jensen, D. Sjoding, C. Kruger, N. Abu-Lail, G. Astill, I. Dallmeyer, M. Flury, A. Fortuna, J. Garcia-Nunez, S. Hall, J.B. Harsh, H. Iqbal, N Kennedy, J. Ma, S. Mitchell, B. Pecha, R. Pelaez-Samaniego, A. Seker, M. Smith, W. Suliman, G. Yorgey, L. Yu, and Q. Zhao. 2016. Publication 16-07-008. Washington Department of Ecology, Olympia, WA.

  • Odor in Commercial Scale Compost

    Ma, J., K. Wilson, Q. Zhao, G. Yorgey and C. Frear. 2013.  Ecology Publication 13-07-066

  • Soil Fertility in Organic Systems: A Guide for Gardeners and Small Acreage Farmers

    Collins,D. C. Miles, C. Cogger, R. Koenig. 2013.  Pacific Northwest Extension Publication PNW646.

  • Soils and Compost

    This WSU Small Farms Team website provides links to various resources on compost science, operations and equipment, compost tea, and vermicomposting.

  • Composts and Nutrient Management

    The WSU Puyallup Research Center faculty have conducted extensive work on compost, manure and biosolids. This website provides information on yard waste and food waste composts, clopyralid, calculating bulk density, nutrient management for organic systems and compost facility operator training events. The site has links to the Compost Mix Calculator the Organic Fertilizer Calculator and Center research publications.

  • Closing the recycling loop through organic amendments in agriculture and gardens

    Recorded webinar (online presentation) from Jan 2011 by Craig Cogger, Crop and Soils Scientist and Extension Educator. This seminar discusses research and guidelines on soil amendment choices based on use, nitrogen availability, carbon sequestration potential, handling nutrient imbalances in organic amendments, and an update on herbicide issues in some composts.

  • On-Farm Composting of Large Animal Mortalities

    Price, C. and L. Carpenter-Boggs. WSU Extension Bulletin EB2021E. 2008. Composting can be a safe and effective method for disposing of on-farm mortalities when the correct procedures are followed and the system is managed well. This bulletin provides the necessary information for large animal producers in Washington State to start and maintain a safe and effective on-farm mortality composting system.

Additional Compost Publications

Browse Publications Library for more


External Links

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