The Devil is in the Process: Co-composting Biochar Could Benefit Crop Growth and the Environment

By Karen Hills

Biochar has the potential to sequester carbon and improve the properties of soils when used as an agricultural amendment. However, biochar will only be a viable option for carbon sequestration if there are uses and viable markets for this biochar. In recent years, there has been interest in adding biochar to agricultural soils in conjunction with compost, and in some cases, “co-composting” biochar—putting the biochar in with the feedstock before the composting altogether. Read on to learn about a study led by Dr. David Gang, a professor at Washington State University’s Institute of Biological Chemistry, indicating that co-composting can provide additional benefits, both during the composting process and to the crops grown in soil amended with the resulting co-composted biochar.

Three people around equipment on a compost pile

Figure 1. Mark Fuchs (left), John Cleary (right) (both of the Washington Department of Ecology) and Nathan Stacey (middle, WSU) use equipment to measure gas emissions from a commercial scale co-composting experiment. Photo: Doug Collins, WSU.

The co-composted biochar used in this study was made using a set proportion of screened dairy manure solids and bedding straw, woody yard waste, and food scraps. Some of the compost piles also contained 2.5% or 5% (by volume) biochar. Even before adding the compost to the soil there were benefits: the addition of biochar to the feedstocks led to significant reductions in the volatile organic compounds measured during the composting process, which can make compost smell bad (Figure 1).

While sweet basil is not considered one of the Pacific Northwest’s major commodity crops, it is a high value crop that is frequently grown under organic conditions, making it well suited to receive high-value organic amendments, such as compost and biochar. Gang and collaborators tested the co-compost by blending it as part of a soil mixture and using it to grow two different cultivars of sweet basil (Eleanora and TSQ) in pots in a greenhouse.

Interestingly, neither compost alone, nor compost with biochar added when applied to the soil, made a difference to the growth of the sweet basil plants. Co-composting the biochar (at 2.5% or 5%), however, caused a significant increase in plant fresh weight relative to treatments receiving a combination of biochar and compost (Figure 2).  This result suggests that something occurred during the co-composting process that affected the co-compost’s ability to promote plant growth.

Left panel shows photos of four basil plants in rows, of different heights. Right panel is a graph showing plant weight for the four different treatments.

Figure 2. Impact of biochar co-composting on biomass/yield of sweet basil cultivar Eleanora (a Genovese type of basil). Different letters indicate significant differences between treatments. (Source: Gang et al. 2018).

Sometimes getting bigger plants can be counter-productive, because the quality can be diluted. Gang and colleagues also measured the effects of the biochar and co-compost treatments on levels of the antioxidants and volatile compounds that create the characteristic flavor of basil. They found very little impact on either antioxidant levels or the production of flavor compounds in sweet basil, per gram fresh weight. This is a very positive result, showing that the higher yields did not result in decreased quality.

The mechanism by which co-composted biochar increased plant growth has yet to be fully understood, but the study authors suggest that these effects may be due to positive impacts on soil health, particularly composition and activity levels of the microbial community. That is, qualities of the co-composted biochar may have helped create a better environment in the soil for microbes that provided benefits to the basil plants.

The only potential downside to using biochar in co-composting is the potential for additional cost associated with the energy for producing biochar. However, biochar cost can be minimized if the energy for its production can be derived from the source materials, and if it and can be produced relatively locally, minimizing transportation costs. Even if there is some cost associated with biochar for co-composting, Gang is optimistic about the potential to offset it by the downstream benefits on crop yield.

Potato seedlings on dark soil

Figure 3. Co-composted biochar spread on experimental field plots before tillage and planting of potatoes. Photo: Doug Collins, WSU.

While positive effects of soil amendments such as biochar and co-composted biochar are dependent on the specific combination of biochar, soil conditions, and crop cultivar, this study raises some interesting questions and the potential for a win-win situation, with benefits seen both during the composting process and for crops grown using the resulting product. If these play out as hoped and the costs of adding biochar are indeed outweighed by the benefits, compost facilities could be in the market for biochar, leading to greater capturing of carbon in this product, in agricultural soils. Gang’s team, working with a number of other collaborators, are currently following up on these intriguing results to test the impacts of biochar co-compost on gas emissions, co-compost quality, and crop yield and quality of sweet basil, strawberries, and potatoes, both in the greenhouse and in the field (Figure 3).

For more information on this project and others funded through the Waste to Fuels Partnership, please see the Waste to Fuels Technology Partnership 2015-2017 Biennium Report.

This work was funded through the Waste to Fuels Technology Partnership between the Center for Sustaining Agriculture and Natural Resources at Washington State University and the Washington Department of Ecology’s Solid Waste Management Program (previously Waste 2 Resources Program). This partnership advances targeted applied research and extension on emerging technologies for managing residual organic matter.

Reference:

Gang, D.R., A. Berim, R. Long, J. Cleary, M. Fuchs, R.W. Finch, M. Garcia-Perez, and B.T. Jobson.  2018.Evaluation of Impact of Biochar-Amended Compost on Organic Herb Yield and Quality. Chapter 10 in Chen, S. et. al. 2018. Advancing Organics Management in Washington State: The Waste to Fuels Technology Partnership. Waste 2 Resources, Washington State Department of Ecology Publication No. 18-07-010. Olympia, Washington. https://fortress.wa.gov/ecy/publications/SummaryPages/1807010.html

 

Check it out: Extreme Winter Weather Severely Impacts the Dairy and Cattle Industry

By Laurie Houston

Person walking through snow to a car buried in a drift which completely covers the fence behind it.

The February 9, 2019 blizzard in eastern Washington dumped 2-3 feet of snow, and winds created drifts that fully covered ditches and fences. Photo: Washington State Department of Transportation under CC BY-NC-ND 2.0.

If you live in the Northwest, you either experienced first-hand or certainly heard about this past week’s blizzard in eastern Washington State.  This area does not usually get much precipitation over the course of a year.  During the winter, they may typically get a few inches of snow in any given storm. This storm, however, took many people by surprise and dumped 2-3 feet of snow in parts of eastern Washington, while bringing in winds from the east and temperatures in the low teens. Over 1,600 dairy cows were killed in this freak blizzard. At an estimated $2,000 per head, that is a loss of $3,200,000, spread over a little more than a dozen farms. That is huge unforeseen expense for struggling farmers to absorb, and a large amount of dead animals to dispose of safely.

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Check it out: New Publication – Cultivating Climate Resilience on Farms and Ranches

By Gabrielle Roesch-McNally

Sunset over a flooded agricultural landscape.

Farms and ranches are expected to face challenges as climate change leads to more extreme and variable weather. Photo: Flickr user Brent M. under CC BY 2.0.

USDA SARE (Sustainable Agriculture Research & Education) recently published a new resource for land managers and those who advise them titled, “Cultivating Climate Resilience on Farms and Ranches.” This resource outlines some of the challenges that farmers and ranchers will face as climate change leads to more extreme and variable weather. While the resource is national in scope, there is a great table that briefly explores the observed and expected changes in weather across seven U.S. regions, including the Northwest (Table 1). Continue reading

Tools for Reducing the Increasing Forest Fire Risks

By Chris Schnepf

Rubble of a burned house, surrounded by scorched trees

Different factors can contribute to homes burning in catastrophic fires, including climate change and where people choose to build. Photo: C. Schnepf.

It was impossible to watch all the media coverage of the California fires last year, with many homes and forests burning, and not be moved. When large destructive fires like this hit, people have a natural desire to put some meaning to it. A variety of voices spoke of the changes in climate as being the culprit. Some pointed to fuel build-ups that were heavier than those forests had historically. Others pointed to people moving into parts of the landscape that were very fire prone, and suggested it was only a matter time before homes burned in forest fires. As with so many things, all these explanations for the impact of the fires contain some truth. Continue reading

Could Wood Plastic Composites Motivate More Investments in Climate-Friendly Anaerobic Digestion?

By Karen Hills

Picture this future scenario: it’s a hot summer day and you are sitting with some friends on their deck enjoying a cold beverage. You notice they recently replaced their deck and, interested, you ask about the decking material they used, only to find out that it’s made partially out of . . . manure from dairy cows! Surprised? Work done by researchers at Washington State University investigated this potential method for adding value to an agricultural waste product.

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Shared Data is a Key Part of Integrated Floodplain Management in the Puyallup Watershed

By Jordan Jobe, Center for Sustaining Agriculture and Natural Resources, Washington State University

In the Puget Sound Region, it’s clear that climate change impacts will involve changes in precipitation that will impact agriculture, especially agriculture in floodplain areas (Mauger et al. 2015). However, it’s not yet known how precipitation pattern changes will combine with changes in stormwater run-off and sea-level rise… and how these changes might differ between different watersheds. Flood risk reduction folks want this information so that they know how to properly size new culverts. Fish folks want this information to place and design salmon habitat restoration projects.

A drainage ditch very full with brown, near-stagnant water.

Nancy’s Ditch, a key agricultural ditch in the Puyallup Watershed’s Clear Creek area, is consistently slow-flowing and full of water. Photo: J. Jobe.

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Engaging Climate Science through Citizen Science Apps

By Chris Schnepf

Queencup beadlily flowering on a forest floor

“Nature’s Notebook” is an app that can be used to collect phenology data such as flower timing. Photo: C. Schnepf.

Trying to understand how climate is changing, and how these changes affect the crop yields, forest growth, water from melting snowpacks, and all the other parts of our natural world, is very challenging. Increasingly, some of the primary tools for understanding these phenomena are models.

One of the biggest misconceptions about models is the idea they are not based in the real world – that they are just theoretical constructs, untethered to actual measurements. There are models like that – even philosophers are playing with models these days. But most of the models used in the natural sciences depend on empirical data – measurements of things like temperature, precipitation, crop yields, tree mortality, and many other attributes. Continue reading

Check it out: The State of the Science on Climate Change in the Pacific Northwest

By Gabrielle Roesch-McNally

The Fourth National Climate Assessment (NCA4) was just released on November 23, 2018. The Global Change Research Act of 1990 mandates that the U.S. Global Change Research Program (USGCRP) provide a report to Congress and the President just about every four years. This report focuses on the human welfare, societal and environmental impacts associated with climate change and variability across 10 regions in the U.S., and across 18 topics of national significance. Many collaborators across the Northwest participated in writing for the Northwest chapter. In this chapter, we outline five Key Messages that illustrate how climate change will impact different aspects of life in the Northwest (Figure 1):   Continue reading

Flexibility is Key to Northwest Cattle Production’s Future Success

By Laurie Houston

The impact of climate change on cattle producers in the Northwest is not expected to be as extreme as other regions of the United States.  According to a recent study led by Shannon Neibergs and published in Climatic Change, Northwest producers have a comparative advantage because droughts will be less severe in the Northwest and they have access to feed via extensive irrigation systems than can mitigate the effects of drought. That’s compared to the rest of the United States, though. But what impacts can livestock producers expect here? Can they continue business as usual? Probably not, but there are clear options moving forward, conclude Neibergs and colleagues. Continue reading

Announcement: Finnriver Farm and Cidery Farmwalk

Farmwalk (text)

WSU Food Systems Program and Tilth Alliance have been collaboratively presenting the FARMWALK series for 15 years! These farmer-to-farmer educational events are hosted on innovative farms throughout Washington State. Check out our latest offering below!

Saturday  –  December 8th – 10am – 3pm

Finnriver Farm and Cidery
Chimacum, WA

Basics of Biochar: On-Farm Kiln and Soil Amendment Options

Register Now!

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