Skip to main content Skip to navigation
Science in action to improve the sustainability of agriculture, natural resources, and food systems
Learn More Program Areas

Compost

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 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 Publications

Dairy Waste Biorefinery

Kennedy, N., C. Frear, M. Garcia-Perez, C. Kruger, and S. Chen. 2013. Concept illustration and description.

Organic Waste Biorefinery

Kennedy, N., C. Frear, M. Garcia-Perez, C. Kruger, and S. Chen. 2013. Concept illustration and description.

Two novel floor-scale anaerobic digester systems for processing food waste. Part 1: Multi-reactor, liquid recycle system for high solids. Part 2: Moderate solids system.

Frear, C., Ewing, T., Yu, L., Ma, J., and Chen, S. 2012. Olympia, WA. Washington State Department of Ecology.

Building Markets for Biofertilizers — Perceptions and Performance

Video of keynote address by Chad Kruger at the 26th Annual BioCycle West Coast Conference April 2012.

Herbicide contamination of dairy derived organic matter in Whatcom County: New developments in 2011

Burrows, C. 2011. WSU Whatcom County Extension. This article is an update on potential aminopyralid residue in manure, composted manure and silage. Mitigation actions include bioassay tests by composting facilities, outreach and education to prevent export of manure from operations where aminopyralid was applied, and proposed product label changes.

Compost Trials in Newly Planted Orchards

Smith, T. 1995-1997. This WSU Chelan-Douglas County Extension website summary features results from in-orchard compost trials in North Central Washington. Report includes an overview of compost materials and use in orchards.

WSU Compost Facility

WSU operates a full scale composting facility on the Pullman campus to recycle organic waste, while providing teaching and research opportunities.

Home Gardening: Compost

A peer-reviewed site for Extension Master Gardeners and homeowners to learn about home gardening, including compost.

Compost Images

An archive of digital photos of various aspects of agricultural composting and compost use to assist agricultural professionals and others in their education programs. Produced as part of the Compost Education and Resources for Western Agriculture project with funding from the Western SARE Program.

Composting in Whatcom County

This WSU Whatcom County Extension website provides information on the Master Recycler/Composter volunteer program and links to compost publications and fact sheets, such as Compost Fundamentals, and Aminopyralid Residues in Compost and other Organic Amendments.