Doug Collins

Doug Collins

Doug Collins

Speaker | WSU Center for Sustaining Agriculture and Natural Resources

Puyallup, WA |

Doug Collins is an Extension Faculty and Soil Scientist with WSU’s Food Systems Program. Doug has a Ph.D. in soil science from Washington State University and an M.S. in Plant Pathology from Montana State University. He focuses on managing and monitoring soil fertility on diverse organic vegetable farms and evaluating soil quality in different vegetable cropping systems – including organic reduced tillage. Doug is also interested in soil variability across landscapes and biological indicators of soil quality.

USCC Member

Session Name: Biochar and Compost: Exploring the Synergies

Session Time: Thursday, January 30, 2:00 to 3:30 PM

Presentation Title: Biochar feedstock influences compost pile temperature and available nitrogen

Presentation Description: Biochar is organic material that has been combusted without addition of oxygen with the intention of using it as a soil amendment. Biochar is porous and has a large surface area which can decrease soil compaction and improve fertility and aggregation. We investigated the effects of biochar on the composting process and on the physical and chemical properties of the starting and finished compost. Biochar produced from Douglas fir and pine was added to a compost mixture at 0%, 20% and 40% v/v.  Compost was a 4:1 wood shavings:chicken manure (v/v) mixture with an initial carbon to nitrogen ratio of 32. Compost was produced in 2 cubic yard aerated static bins with 3 bins (replications) per compost mixture for a period of 60 days. Physical and chemical properties were measured from the initial compost mixtures and at the completion of the study. Pile temperature was measured continuously in each bin.  All piles heated to greater than 170 F, but control piles (no biochar) remained above 160 F for 10 days, while 20% biochar dropped below 160 F at 5 to 6 days and 40% biochar below 160 F at 4 days.  pH and electrical conductivity in the final compost were reduced with 40% biochar. Total nitrogen in finished piles was not different with biochar, but total carbon and carbon to nitrogen were increased with 40% biochar. Compost produced with biochar had a greater concentration of nitrate nitrogen and a decreased concentration of ammonium nitrogen. Bioassays of the finished product are underway. Utilizing biochar as a feedstock altered compost physical properties and temperature dynamics during the composting process and influenced nitrogen availability in finished compost and has potential to produce a high value specialty product.

Co-Authors: Nathan Stacey, Ph.D, WSU Center for Sustaining Agriculture and Natural Resources,
Thida Tea, Pacific Lutheran University,
Andy Bary, WSU Puyallup Research and Extension Center,
Liz Myhre, WSU Puyallup Research and Extension Center,