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Doug Collins

Doug Collins

Extension Specialist Kalkus Hall 232A 2606 W. Pioneer Puyallup, WA 98371

Doug Collins is an Extension Faculty with the Center for Sustaining Agriculture and Natural Resources and an affiliate faculty with the WSU Department of Crop and Soil Sciences. His extension programs and research focus on soil quality and vegetable and fruit production for small farms.  Doug has a Ph.D. in soil science from Washington State University, an M.S. in Plant Pathology from Montana State University, and a B.A. in biology from Colorado College. He previously worked for Ribeiro Plant Lab, Inc., Seattle Tilth Association and the Washington Toxics Coalition and served on the board of directors of Tilth Producers of Washington. He currently serves on the Washington State Department of Agriculture Organic Advisory Board.

Doug is an active instructor in Ecological Soil Management for beginning and advanced producers. He conducts workshops at area conferences and for Cultivating Success™ classes. Doug’s research program is focused on organic vegetable cropping systems and managing and monitoring soil fertility.

Areas of interest include:

  • Managing and monitoring soil fertility on diverse organic vegetable farms
  • Organic vegetable cropping systems, including reduced tillage
  • Soil variability across landscapes
  • Biological indicators of soil quality


Collins, D.P. and A. McGuire. 2019. Understanding and measuring organic matter in soils. WSU Extension Manual, EM118E

Shahzad, K., A. I. Bary, D. P. Collins, L. Chalker-Scott, M. Abid, H. Y. Sintim, and M. Flury. 2019. Carbon dioxide and oxygen exchange at the soil-atmosphere boundary as affected by various mulch materials. Soil and Tillage Research. 194. 1-10.

Cogger, C, A. Bary, A. Fortuna, L. Myhre, and D.P. Collins. 2016. Soil physical properties, nitrogen, and crop yield in organic vegetable production systems. Agronomy Journal. 108:1142-1154

Collins, D.P., H. Harness, and A.I. Bary. 2016. Commercial compost application on western Washington Farms. Biocycle. 57(3):63-65.

Collins, D.P, C. Benedict, A.I. Bary, C. Cogger. 2015. Soil mapping and ad hoc power analysis to increase blocking efficiency prior to establishing a long-term field experiment. Scientific World JournalArticle ID 205392: 1-8.

Wayman, S., C. Cogger, D. P. Collins, C. Benedict, I. Burke, and A. Bary. 2015. Cover crop effects on light, nitrogen, and weeds in organic reduced tillage.  Agroecology and Sustainable Food Systems. 39:6, 647-665, DOI: 10.1080/21683565.2015.1018398

Collins, D.P., C. Miles, C. Cogger, and R. Koenig.  2013.  Soil fertility in organic systems: A guide for gardeners and small acreage farmers.  Pacific Northwest Extension Fact Sheet, PNW646.

Collins, D.P.  2012.  Soil testing:  A guide for farms with diverse vegetable crops.  Washington State University Extension Fact Sheet.  EM050E.

Collins, D.P., C.G. Cogger, A.C. Kennedy, T. Forge, A.I. Bary, H.P. Collins, and R. Rossi. 2011.  Farm-scale variation of soil quality indices and association with edaphic properties.  Soil Science Society of America Journal. 75 (2): 580-590.

Wayman, S., C. Cogger, C. Benedict, I. Burke, D. Collins, and A. Bary.  2014.  The influence of cover crop variety, termination timing, and termination method on mulch, weed cover, and soil nitrate in organic reduced-tillage.  Renewable Agriculture and Food Systems. FirstView: 1-11.

Wayman, S. and D. Collins. 2013. For the life of the soil:  Farmer perspectives and experiences adopting reduced tillage organic agriculture.  Tilth Producers Quarterly. 23 (4): 1, 4-5.

Hoashi-Erhardt, W.K.,  P.P.Moore, D.P.Collins, A.I.Bary, and C.G.Cogger.  2013.  Evaluation of day-neutral cultivars for organic strawberry production in Washington.  Acta Horticulturae (ISHS) 1001:167-174

Corbin, A., D. Collins, R. Krebill-Prather, C. Benedict, and D. Moore. 2013. Adoption potential and perceptions of reduced tillage among organic farmers in the maritime Pacific Northwest.  eXtension Foundation, eOrganic Community of Practice. [Online].

Collins, D.P.  2013.  Seasonal nitrogen mineralization on organic farms.  Tilth Producers Quarterly.  23 (1): 1,4-5.

Collins, D.P., A. Corbin, C. Benedict, C. Cogger, A. Bary, C. Burrows, and C. Miles.  2011.  Reducing tillage with cover crops in western Washington organic vegetable production:  early research progress and future direction. Tilth Producers Quarterly. 21 (2): 15-19.

Collins, D.P., Koenig, K.; Berman, F.  2011.  Passing knowledge through hands-on experience:  legal farm internships in Washington State.  Tilth Producers Quarterly. 21 (1): 8-11.

Collins, D.P.  2011.  Nitrogen availability from soil organic matter, fertilizer, and amendments.  Tilth Producers Quarterly. 21 (1): 12-13.

Collins, D.P.  2011.  Report card nitrate test for assessing fertilizer efficiency. Tilth Producers Quarterly. 21 (3): 11.

Collins, D.P. and B. J. Jacobsen.  2003.  Optimizing a Bacillus subtilis isolate for biological control of sugar beet cercospora leaf spot. Biological Control.  26 (2): 153-161.

Collins, D.P., B. J. Jacobsen and B. Maxwell.  2003.  Spatial and temporal population dynamics of a phyllosphere colonizing Bacillus subtilis biological control agent of sugar beet cercospora leaf spot.  Biological Control.   26 (3):  224-232.


2019-2020    Collins, D. N. Stacey Rotating out of weeds and into soil health: Successful cover cropping and tillage strategies for organic vegetable production in the Columbia Basin. $39,993. WSU BIOAg. $39,993.

2019-2022  Collins, D. N. Andrews, L. Golden, C. Sullivan.  On-Farm Cover Crop Use, Evaluation, and Data Sharing with the Western Cover Crop Council. SARE Research to Grass Roots. $50,000

2019-2022  Collins, D., N. Stacey, A. Seigner. Investigating the elasticity of biochar: manure handling, compost feedstock, soil amendment and carbon storage. SARE Professional plus Producer. $50,000.

2018-2020  Collins, D.P, B. Ewing, L. Carpenter-Boggs, S. Smith, and G. Ganjyal Sustainable High-Value Horticulture and Processing Systems in Washington State: AFRI REEU. $278,911.

2018-2019  Gang, D., D.P Collins, W. Hoashi-Erhardt, M. Garcia-Perez, and T. Jobson.  Integrating compost and biochar for improved soil health, crop yield, and air quality. WA Department of Ecology Waste to Fuels Technology. $113,551.

2015-2017  Collins, D.P. and A. I. Bary. Optimizing N Management on Organic and Biologically Intensive Farms. Western SARE. $49,996.

2014-2017  Collins, D., C. Benedict, A. Corbin, A. Bary, C. Cogger. Increasing adoption of reduced tillage strategies on organic farms in the maritime Northwest.  Western SARE, $249,949.


Introduction to R.  Two 4-hour classes at the WSU Puyallup Research and Extension Center, summers 2013, 2015-2019.

Environmental Science 317: Soils Laboratory, University of Washington, Bothell, guest lecturer and lab instructor, nematodes and soil quality indicators. 2-hour class, Spring 2019.

Biology 116: Introductory Ecology, Pacific Lutheran University, Tacoma, WA, guest lecturer and lab instructor, soil quality indicators. Two 4-hour classes, fall 2009 and 2017.

Horticulture 104: Introduction to Agroecology. Edmonds Community College. Guest lecturer, Soil Organisms. One 2-hour presentation, Fall, 2016.

Biology 240: The Urban Farm. University of Washington. Guest lecturer, Reduced Tillage Organic Agriculture. One 1-hour seminar, Fall, 2015.

Soils 201: Soil: A Living System. Washington State University. Guest lecturer, Organic Soil Fertility. One 1.5-hour seminar, Spring, 2015.

Practice of Sustainable Agriculture, The Evergreen State College.  Guest lecturer, Nitrogen mineralization on Organic Farms and soil fertility planning.  One 3-hour seminar, summer, 2013.


Sullivan D. and D.P. Collins. 2018. Reduced tillage in organic vegetable production. WSU Extension Video. [Online].

Collins,D.P. and J. Garcia-Pabon  (Producers) 2013.  “Cosecha y empaque de lechugas Romanas para sanidad y calidad.” (Harvesting and packing Romaine lettuce for safety and quality).  Writer:  S. Schaeffer; Editor: T. Cogger.  [online]


Collins, D.P. 2019. The importance of on-farm research. Organicology, Portland, OR. Invited Speaker.

Stacey, N.E, D.P. Collins, S. Seefeldt, D. Gang, M. Flury, W. Hoashi-Erhardt. 2019. Co-composting biochar: Amendment in agricultural soils. Soil Science Society of America, San Diego, CA. Poster Presentation.

Collins, D.P. 2019. Reduced tillage in organic vegetables. Small Farm School, Clackamas Community College, Oregon City, OR. Invited Speaker.

Cappellazzi, S., D.P. Collins, D. Griffin. 2019. Soil sampling. Healthy Soils, Healthy Region Workshop, Pendleton, OR.

Collins, D.P. 2019. Tiny houses, between the sheets, and the debris field: The structure and composition of soil organic matter and implications for management. Management Matters for Soil Health Conference, Pullman, WA. Invited Speaker.

Collins, D.P. 2019. The importance of soil organic matter: Why it matters, what it does, and where it is. Healthy Soils, Healthy Region Workshop, Pendleton, OR.

Collins, D.P., C. Benedict, D. Sullivan, A. Bary, L. Myhre. 2017. New tools and techniques for high residue organic vegetable strip tillage in the Maritime Pacific Northwest. Soil Science Society of America. Poster Presentation.

Collins, D.P., A. Bary. 2017. Optimizing nitrogen management on organic and biologically-intensive farms. Soil Science Society of America.


Leslie Michel, M.S. expected completion 2020. Project: Grazing cover crops for soil health in low-rainfall Eastern Washington.

Emily Blessington, M.S. expected completion 2021.

Ryan Tarbell, M.S. completed May 2019 (committee chair). Thesis: The influence of tillage on vetch cover crop decomposition, N availability, and broccoli yield in organic reduced tillage agriculture.

David Sullivan, M.S. completed December 2017. (committee chair). Thesis: Cover crop-based strip tillage for organic vegetable production in the Pacific Northwest.

Nathan Stacey, Ph.D. completed December 2017. Project: Composted biosolids as a nutrient substitute for golf course fairways.

Rebecca Collier, M.S. (Iowa State University) completed spring 2017. Thesis: Nitrogen release and decomposition by cover crops in reduced-tillage organic systems

Bethany Wolters, M.S. completed May 2015 (committee chair). Thesis:  Greenhouse gas emissions in no-till vegetable production.

Patrick O’Neill, M.S. completed Aug 2015. Thesis: Columbia root knot nematode management in potatoes using rotational crops under cool-climate conditions

Justin Ruiz, M.S completed fall 2015. Project: Food Waste – Derived Organic Fertilizer for Golf Courses


Thida Tea, completed summer 2019. Project: Biochar influences compost temperature and available nitrogen

Taylor Enns, completed summer 2018. Soil quality improvements with biochar and compost

Naomi DuBois, completed winter 2019. Increasing corn yield through tillage and cover crop management

Tuong Vu, completed winter 2017; Project: Optimizing nitrogen fertility on organic farms

Holly Lane, completed winter 2016; Project: The effects of reduced tillage on soil moisture, temperature, and light intensity in organic vegetable systems; Poster awarded Gray award at WSU Showcase for Undergraduate Research and Creative Activities (SURCA)

Christian Bush, completed winter 2015

Kyle Saxe, completed winter 2013

Katrina McCann completed spring 2013. Awarded Soil Science Society of America Golden Opportunity Scholar, 2011.

McCann, K., D.P. Collins, C. Cogger, and A. Bary.  2011.  Variation in soil collembolan populations and microbial biomass on western Washington organic farms.  Soil Ecology Society Bi-Annual Meeting, Kelowna, British Columbia.  Poster Presentation.

McCann, K., D.P. Collins, C. Cogger, and A. Bary.  2011.  Estimating long-term compost application effects on active soil carbon with 24-hour basal respiration.  Proceedings of the Soil Science Society of America, San Antonio, TX.  Poster Presentation.