As I mentioned in my last blog post, Extension Master Gardeners in Minnesota and Iowa are researching whether biochar would be a suitable soil amendment in home gardens.
Biochar can come from many different products, from grasses to hardwoods, and from most anything that can burn. Before I move forward, I need to back up here a little. In the bigger picture of the CenUSA Bioenergy project, one of the goals is to develop sustainable perennial grasses as primary energy crops for the purpose of developing biofuels. (Learn more in this Harvesting Native Grass for Biofuel Production YouTube video.)
When the time comes that perennial grasses will be used on a regular basis for biofuel production, there will be a lot of byproduct that could be repurposed in the form of granulated biochar, and one way that biochar be can used is as a soil amendment.
What Biochar Are We Using in Test Gardens? Why?
Now, you might be thinking there is a twist to this story because the biochar we are using and evaluating in test plot gardens is not from grasses, but actually from hardwood (shrub and tree) species! Why, you ask?
Ideally we were hoping to find biochar that was processed from switchgrass or other perennial grasses. Since biochar is a relatively new product and very few processing plants are licensed to produce it, especially in the quantities we needed, we welcomed the next best option.
We did find biochar in the granular size that we needed from Royal Oak charcoal company. The biochar they had was processed from hardwoods. The decision makers at Royal Oak were interested in being part of our research project so they were gracious enough to donate it.
The grass and hardwood biochars may not be the same, but at least they are similar. It’s not like using biochar from feathers, manure or pine needles. And, since there is much we (researchers) do not know about using biochar in gardens, researching one type of biochar across multiple test plots in several states will give us clues to see how the same biochar reacts in different soils and climates.
Remember, our overall objective is to replicate gardens that a typical homeowner would have, so we wanted a variety of soil types to test and while we are testing only one form of biochar, there are other researchers testing many other kinds.
Adding Biochar to Gardens Using Biochar Safety Sheets and Guidelines
The biochar was shipped in 50 pound bags. It had a granular texture and was about the size and consistency of course fertilizer. I have been asked if biochar has an odor…and the answer is YES. It smells like burnt wood but it wasn’t too strong, and the odor doesn’t linger. You may get an urge to roast some hot dogs and marshmallows initially, but not for long.
Before we could apply the biochar to the test gardens, we asked some of our CenUSA Bioenergy partners to develop safety guidelines for applying it. Since this product is not on the consumer market, those kinds of things had not taken place yet.
We did learn that biochar is considered a combustible material and there are specific guidelines on how best to store anything ignitable. In addition, biochar can be dusty so it was recommended to not apply it on a windy day. We were also advised to wear dust masks, gloves and protective clothing….mostly to protect from the dust.
Applying the biochar was fairly easy. We just cut open the end of each bag and carefully dragged them across the areas we wanted it and then rototilled it in to a depth of about 6 inches. If we were to apply this on a larger plot of land, it could be applied with a fertilizer spreader. The way we did it had very little dust. For the purpose of this research, biochar will only be applied the one time.
The next steps past amending the soil with biochar was in prepping, and planting the gardens, but we’ll get to that next week, as we continue to blog about our biochar research story through the CenUSA Bioenergy project.
by Lynne Davenport-Hagen
University of Minnesota Extension
Master Gardener Program Coordinator-Anoka County
CenUSA Biochar Research & Display Garden Project Coordinator-USDA NIFA Grant
“The CenUSA Bioenergy project is supported by Agriculture and Food Research Initiative Competitive Grant No. 2011-68005-30411 from the National Institute of Food and Agriculture.”