Growing Organic Blueberries Using Biochar

Problem

My goal is to raise blueberries sustainably on 1⁄2 acre of pasture land. The soil is heavy loess clay on top of a hill. In order to produce blueberries I will need to amend the soil significantly. I’m planning on using biochar on 1⁄4 acre along with our usual sustainable practice using mulch and organic amendments. The other 1⁄4 acre would use the same practice minus the biochar.

Biochar is a type of charcoal that is produced by heating air-dried plant material (biomass) in a setting without oxygen. Biochar can store moisture and nutrients in the soil. Properly produced biochar provides a good environment for essential microorganisms to grow. These microorganisms play a major role in nutrient cycling within the soil environment. Biochar has been proven to have a significant impact when using a holistic approach to sustainable food production.

One problem with using biochar in blueberry production is that biochar has a naturally high pH. This is, of course, the inverse of what is desirable when raising blueberries. Our pH is already 6.9. Depending on what medium is used to make the biochar the pH can be between 7-9. Also, the effectiveness of biochar can be inconsistent and not all biochar is equal.

Solution

The pH problem can be solved by washing the biochar according to Dr. Bayan of Lincoln University, our local expert on biochar. After washing and charging the biochar it becomes a pH stabilizer.
The effectiveness of biochar is more consistent when it is charged. Basically biochar is fairly inert. My goal is to make the biochar using the techniques outlined by Dr. Bayan and charge it in a compost stew with other amendments added that are beneficial to blueberries and then adding that to the top 6 inches of native soil creating 12 inches of loamy topsoil.

One-quarter acre will be sustainably grown but without biochar. The other 1⁄4 acre will be grown using biochar at 3%. This means I will need to produce 3000 lbs. of biochar. Each batch should make approximately 30 lbs. so I will need to burn 100 batches. I plan to build two double-barrel slow pyrolyzers. I should be able to create 3000 lbs in approximately two months. I have a free source of ramial wood chips.

After two years I expect to see significantly more foliage on the biochar blueberries. One does not harvest blueberries the first or second year (fruit is picked off to encourage plant growth), but I will weigh the blueberries that are picked off and document foliage development over the two years of the study. After the study is over I will still report yields.

1. Determine whether biochar can be a useful soil amendment when growing blueberries in highly alkaline heavy clay soils.
2. Provide the environmental benefits of biochar use including reduction of atmospheric carbon dioxide, retaining nutrients in soil and reducing the need for fertilizer, and prevention of water quality problems by preventing runoff of nitrogen and phosphorus.
3. Show that growing blueberries organically in the Kansas City area can be sustainable and profitable by using biochar, which may increase yield and protect against drought.
4. Benefit farmers socially through sharing of knowledge, resources, and experiences about organic food production, and the community by creating a welcoming orchard.