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Washington State University - Puyallup Organic Farming Systems and Nutrient Management

Compost and Nutrient Management


Composting stabilizes organic wastes, reducing nutrient availability, allowing their use at high application rates as a soil amendment. Composts do affect available nutrient levels in soil, often causing short term immobilization (tie-up) of nitrogen, but a long term slow release. We have evaluated effects of compost applications on nitrogen availability and soil properties.

♣ Compost Operators Training at WSU Puyallup: Training and certification for Compost Facility Operators, Managers, and officials involved with Composting. Hands on composting, field trips, exam.

♣ Yard Trimmings. Yard trimmings are organic materials such as lawn clippings, leaves, and pruned material that is applied, without any processing, directly to soil to be amended.

♣ Compost Analysis. How to sample and prepare your compost to send to a laboratory for analysis, how to choose a laboratory, how to decipher laboratory results.

♣ Food Waste Compost Earthtub Composting Project. Small on-site composter used to compost school lunch program food waste as well as educate students.

♣ Calculating Compost Bulk Density. How to calculate bulk density of composts and compost- type materials such as manures and yard waste.

♣ Clopyralid in Compost.  Facts and background about the Clopyralid contamination problem.

♣ Compost Mixture Calculator. The Compost Mix Calculator version 2.1 is an Excel xls spreadsheet (for computers) or an Online App (for tablets or phones) that calculates compost mixture C:N ratio and moisture content, based on the analysis of your feed stocks and the mixture proportions that you choose. You can use the spreadsheet or App to evaluate the effects of different feedstock mixtures on C:N ratio and moisture content of the initial pile.  The Excel file version also calculates material bulk density and free air space.


♣ Oregon State University Department of Crop & Soil Science, compost resources.

♣ Washington State Department of Ecology, Composting, Siting and Operating Compost Facilities in Washington State publication, & other publications and resources.

♣ Washington Organic Recycling Council, information, training, events.

♣ The Art and Science of Composting, (pdf) Univ. Wisconsin-Madison

♣ Cornell Composting, educational materials, programs, links.

Photo of small compost bins.

Photo of Earth Tub composting bin.

Photo of large scale aerated compost pile.

Photo of tractor mixing compost.

Extension Publications:


♣ Interpreting Compost Analyses (PDF/HTML-Online), Sullivan, D.M., A.I. Bary, R.O. Miller, and L.J. Brewer. 2018. Oregon State University Extension Bulletin EM9217.  Compost can return nutrients and organic matter to the soil, a proven practice for soil health enhancement. This publication focuses on selecting a lab to perform compost analyses, determining which compost analyses are most relevant to your needs, assessing whether compost is sufficiently stabilized, and avoiding over application of composts high in soluble salts or composts with a pH unsuited to your crop.

♣ Backyard Composting (PDF-Online), Cogger, G., D.M. Sullivan, A. Bary. 2017. Washington State University Extension Bulletin EB1784E.

♣ Washington State Compost Educator’s Guide (Request pdf e-copy), Wescott, H., A. Bary, C. Cogger, C. Sullivan, and A Mack. Washington St. Univ. The purpose of the guide is to: provide consistent, science-based information about residential composting and vermicomposting for use in Washington State, assist compost educators in creating training events such as workshops, and inspire a clear vision for home composting as a cornerstone of sustainable living.

Research Publications:

♣ Urban Highway Roadside Soils and Shrub Plantings are Enhanced by Surface Applied and Incorporated Organic Amendments (Request pdf e-copy). Bary. A. R.L. Hummel, and C. Cogger. 2016. J. Arbor. Urban Hort. 42:418-427.

♣ Fate of Antibiotics and Antibiotic Resistance During Digestion and Composting: A Review (Request pdf e-copy). Youngquist, C.P, S.M. Mitchell, and C.G. Cogger. 2016. J. Environ. Qual. 45:537-545. doi:10.2134/jeq2015.05.0256

♣ Antibiotic Degradation During Thermophilic Composting (Request pdf e-copy). Mitchell, S.M., J.L. Ullman, A. Bary, C.G. Cogger, A.L. Teel, and R.J. Watts.  2015. Water Air Soil Pollut. 226:13.

♣ Soil and Redosier Dogwood Response to Incorporated and Surface-Applied Compost (Request pdf e-copy). Cogger, C., R. Hummel, J. Hart, and A. Bary. 2008. Hortsci. 43:2143–2150.

♣ Comparison of a Gas Detection Tubes Test with the Traditional Alkaline Trap Method to Evaluate Compost Stability (Request pdf e-copy). Benito, M, A. Masaguar, A. Moliner, C.G. Cogger, and A.I. Bary. 2005. Biol. Fertil. Soils 41:447-450.

♣ Potential Compost Benefits for Restoration of Soils Disturbed by Urban Development (Request pdf e-copy). Cogger, C.G. 2005. Compost Sci. Utiliz. 13:243-251.

♣ Nitrogen Availability Seven Years After a High-Rate Food Waste Compost Application (Request pdf e-copy). Sullivan, D.M., A.I. Bary, T.J. Nartea, E.A. Myhre, C.G. Cogger, and S.C. Fransen. 2003. Compost Sci. Util. 11:265-275.

♣ Food Waste Compost Effects on Fertilizer Nitrogen Efficiency, Available Nitrogen, and Tall Fescue Yield (Request pdf e-copy). Sullivan, D.M., A.I. Bary, D.R. Thomas, S.C. Fransen, and C.G. Cogger. 2002. Soil Sci. Soc. Am. J. 66:154-161.

♣ Fertilizer Nitrogen Replacement Value of Food Residuals Composted with Yard Trimmings, Paper, or Wood Wastes (Request pdf e-copy). Sullivan, D.M., S.C. Fransen, A.I. Bary, and C.G. Cogger. 1998. Compost Sci. 6(1):6-18.

♣ Slow-Release Nitrogen From Composts: The Bulking Agent is More Than Just Fluff (Online abstract with pdf chapter or ebook available for purchase). Sullivan, D.M., S.C. Fransen, A.I. Bary, and C.G. Cogger. 1998. p. 319-325. In: S.L. Brown, J.S. Angle, and L.W. Jacobs (ed.) Beneficial co-utilization of agricultural, municipal, and industrial by-products. Kluwer Academic Publishers, Dodrecht, The Netherlands. [book chapter]

Photo of covered compost pile.