Investigating the elasticity of biochar: manure handling, compost feedstock, soil amendment and carbon storage.

View the project final report

Commodities

• Vegetables: cabbages
• Animals: bovine

Practices

• Animal Production: manure management
• Crop Production: nutrient management
• Natural Resources/Environment: carbon sequestration
• Soil Management: composting

Investigating the elasticity of biochar: manure handling, compost feedstock, soil amendment and carbon storage.

Our collaborative team of beef producers, commercial composters, diversified vegetable farmers, and research and extension professionals will assess the impacts of biochar on manure handling, composting, and soil quality in western Washington. Biochar feedstocks will be sourced locally, from both coniferous and deciduous woody biomass.  Two biochar products from two different locally sourced feedstocks will be added to cattle bedding at Midnight’s Farm in a controlled, replicated experiment that will assess the influence of biochar on nutrient content of the bedding feedstock. The bedding- biochar blends will then be co-composted with other on-farm feedstocks at Midnight’s Farm, which is a Department of Ecology farm-exempt facility. The finished compost will be tested for agronomic mineral concentrations, and along with compost-only, biochar-only,  and no amendment control, the co-composted products will be amended to research plots on two participating farms (Lopez Harvest and Helsing Junction), and cropped to cabbage. Following the growing season, crop yield will be measured, and soils from research plots will be tested for nutrient content and carbon dynamics. Participating farms will conduct education and outreach activities related to biochar application in the form of on-farm demonstrations, workshops, outreach to other western state extension professionals, and field trips from local schools. This collaboration is especially well suited to take on this project as it combines two extension professionals from WSU, a U.C. Berkeley graduate student with farm to school educational expertise, one biochar consultant, and five producers. The combined expertise and enthusiasm of this group lends great momentum to the research question at hand: can biochar be a multi-use farm product that improves farm based co-composted products and vegetable production, and promotes soil C sequestration?

The objectives of this Professional + Producer collaboration are to answer the following questions: what are the physicochemical effects on livestock bedding when different biochars are incorporated, and then composted? Subsequently, what is the effect of biochar co-compost on promoting plant growth, soil health, and fertility? Specifically, our objectives include:

1. Evaluate two different biochars, one sourced from coniferous woody biomass and the other from deciduous woody biomass, as livestock bedding additives and test whether biochar incorporation improves feedstock nutrient concentration (i.e., nitrogen).  Assess whether the different bedding feedstocks (i.e., 2 different biochar blends and a control) alter the physicochemical properties of finished composts (e.g., water content and nutrient concentration).
2. Demonstrate, compare, and document effects of co-compost, compost, and biochar soil amendments related to:
   1. Crop yield in field application
   2. Soil health and fertility
3. Evaluate biochar as a carbon storage farming practice.
4. Educate other farmers in the region interested in producing and/or applying biochar to their farming systems on how to do so and what to expect (from the feedstocks used in this trial).
5. Educate other researchers and cooperative extension specialists about biochar co-compost applications and how to communicate and advise interested farmers.

The long-term goal of this project is to improve soil and water quality while sequestering carbon in soils. Our objective is to evaluate the nutrient content of two biochar blended, cow bedding feedstocks, observe and document how the resulting composts differ, and then test the different co-compost as soil amendments.  We hypothesize that: 1) blending biochar into cow bedding will result in greater N retention, reducing the potential for environmental loss, 2) adding the biochar bedding blend to compost will increase nutrient content, thereby adding value to the compost product, and that 3) compost with biochar as a feedstock will lead to increased soil carbon, cation exchange capacity, and pH when applied to soil.