How biochar could help farmers grow better crops

  • December 3, 2019
Local author and policy researcher Jack Petree

As farmers become increasingly focused on soil health to improve their operations, one of the tools people are talking about is biochar. But what is biochar, and what can it really do? Local author and policy researcher Jack Petree has reported extensively on biochar for farming and forestry publications nationwide, and he spoke to Dillon Honcoop to explain what it’s all about.

Petree explains that biochar is represented by the “black chunks” remaining when biomass — wood, bushes, grasses, canes, other organic materials found — is charred but not completely burned. 

“If you have a campfire and you throw a shovel of dirt on it, and dig up a while later, you probably have biochar,” Petree said. “The difference [between biochar and charcoal] is biochar is basically generic term for charcoal like product used for biological purpose as opposed to generate heat.”

He says that charcoal is meant to be reheated up but biochar is meant to be ground up and reintroduced into the soil. Biochar is never fully burned either. Biochar can’t be relit like charcoal. Volatile organic chemicals get burned out of the materials. 

“When you heat organics in an oxygen starved situation you get an irreversible decomposition of the organic material,” Petree told Dillon. 

Because of the way the organic material is burnt, the organic material doesn’t give up the carbon. So, when biochar is introduced to the soil, most of the carbon that was in the material gets introduced to the soil as well. The carbon will bind with heavy metals, potassium and other materials in the soil. By binding together, they bind for thousands of years and will release other nutrients more slowly.

“If you spread it on a field where you have been spreading fertilizer — when you spread fertilizer much of the nitrogen is lost — biochar will bind to it and then release slowly so you get more use out of your fertilizers,” Petree said. 

Biochar is being used a lot as a soil amendment in high value fruit and vegetable crops. It’s being used heavily in greenhouse and nursery operations because the cellular structure will soak up water, which is slowly released back into the soil. It’s been even seen to help with E. Coli breakouts. Mostly, because of the binding and slow release of nutrients. 

“Typically, people are reporting really good impacts,” Petree said. “Partly because the use of biochars always the use of fertilizers to be more efficiently applied.”

Petree also says the Department of Agriculture has done hundreds of studies which show the benefits of biochar. 

Some people are even feeding biochar to their dairy cows, allowing the biochar to bind with the chemicals and methane in their stomachs, affecting any greenhouse gas emissions. 

One of the biggest problems with biochar is the accessibility and production of it. 

“The equipment is just beginning to catch up to the need,” Petree said. “The other problem is there is not a large realization of what biochar is and what it can do.”

Petree says it just takes time for people to know they can rely on it.