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Biosolids as a Value-Added Product
Dan M. Sullivan
Soil Scientist
Crop & Soil Science
Oregon State University
Biofest. Chelan, WASept, 2018
Principles
• Product knowledge (today’s topic)
• Know your region
• Take advantage of local alliances
• Listen to the plants\crops
• Listen to the customers
• “Bloom where you are planted”
Product knowledge
• Think in terms of the customer
• Biosolids are usually a replacement for an existing fertilizer or soil amendment
• How does your biosolids product compare to competition?
How biosolids are unique
• Biosolids have more consistent properties than manure or most competing organics
• Biosolids are low in soluble salts (electrical conductivity)
• Biosolids are an especially effective amendment to increase soil organic matter
How biosolids are unique
• Composts. Applied at high rates, biosolidscomposts acidify soil. Manure or yard debris composts increase soil pH. So biosolids compost is ideal for rhodies…
• High pH soils (calcareous). Biosolids are effective source of metal micronutrients like zinc.
New publication from OSU: Interpreting compost analyses, available online Oct 2018
Research review
1. Nutrients in biosolids
2. Balance of nutrients supplied by biosolids vs. crop needs
3. Persistence of of biosolids organic matter in soil
4. Biosolids compost for ornamentals
Pacific NW Extension publication 508-E
Nutrients
Biosolids: fertilizer replacement value of nutrients
Nutrient balance
• Biosolids supply more P than crops need
• Long term application of biosolids builds soil P, sometimes to excessive levels
Agronomic and environmental interpretations of soil test P.
Soil phosphorus (Olsen P test) after five biosolids applications (over 16 yr)
Douglas County, WA
East of Cascades: long term research. New publication: PNW 716.
Soil organic matter (carbon or C) after five biosolids applications (over 16 yr)
Douglas County, WA
Long term findings: dryland wheat
• Biosolids increased soil organic matter (4 to 6 inch depth) by more than 50%
• Biosolids enriched supply of immobile nutrients (e.g. P and Zn)
• Biosolids were an effective replacement for N fertilizer for the crop following application
• Soluble salt accumulation was minimal
• Wheat grain yield was sometimes increased by biosolids (compared to commercial N fertilizer)
Comparing carbon sequestration of biosolids vs. other organicsPendleton, OR. 10-yr trial
Biosolids were most effective C input to sequester C in soil
Biosolids effective pasture input at 6-8 inch rainfall dryland site
Echo, OregonCity of Portland biosolids
with biosolids
no biosolids
Biosolids effective pasture input at 6-8 inch rainfall dryland site
Echo, OregonCity of Portland biosolids
Biosolids compost vs. yard debris compost trial, western Oregon
Year
2009 2010 2011 2012
So
il p
H (
1:1
me
tho
d)
5.0
5.2
5.4
5.6
5.8
6.0
6.2
6.4
Biosolids compost acidified soil
Biosolids compost
Yard debris compost
No compost
Acid-loving plant (Pieris japonica)
yard debris
compost
biosolids
compost
June 2014. Six years after transplanting
Thank [email protected]