Most people probably don’t think about soil as a living thing. But it is filled with millions of tiny organisms that play a critical role in everything soil does – including sequestering carbon.

Soil contains a diverse array of microorganisms including fungi and bacteria that perform vital functions such as breaking down organic matter, nutrient cycling, and carbon sequestration.

“Microbes — you may not see them with the naked eye, but that doesn’t mean they’re not important,” says Yogesh Kumar ‘27 (CAHNR), a Ph.D. student in the Department of Natural Resources and the Environment.

Thanks to these microbes, soil holds onto a tremendous amount of the earth’s carbon. By supporting the functioning of these microorganisms, a substance known as biochar can improve soil’s ability to serve as a much-needed carbon sink.

Biochar is a charcoal-like substance made by burning organic waste, such as, generated by forestry and agriculture. Biochar has recently emerged as a “Climate-Smart Agriculture” practice given its potential to improve soil health, nutrient and available water holding capacity, resilience, and agricultural sustainability without the negative environmental consequences associated with traditional fertilizers.

A team in the College of Agriculture, Health and Natural Resources is developing a fuller picture of its environmental and agricultural benefits.

Their recent publication in Biochar highlights how biochar supports soil microbes.

Kumar is the lead author on the paper. Other authors include Wei Ren, associate professor of natural resources and the environment; Haiying Tao, associate professor of soil nutrient management and soil health; and Bo Tao, assistant research professor of natural resources and the environment.

The researchers looked at data from hundreds of field studies conducted all around the world to determine biochar’s impact on soil microbes.

On average, biochar application improved soil microbial biomass carbon (SMBC) by approximately 21%.

“When we conducted global data analyses, we found how biochar as a stable carbon influences soil features, particularly microbial activities leading to changes in microbial carbon,” Ren says. “That in turn influences soil’s physical and chemical characteristics and carbon storage.”

A piece of biochar has many tiny pores all over its surface. Microorganisms move into these holes and feed on the carbon, nitrogen, and other essential nutrients the biochar provides. This is especially important in nutrient-deficient soil or soil with a suboptimal pH which would not otherwise be able to support a diverse population of microbes.

“It provides food, nutrients, and a habitat for those microbes,” Kumar says.

The researchers also found that biochar is more effective when used in combination with other management practices, like the use of compost or manure.

By limiting the scope of their analysis to field studies, which take place in real-world conditions, rather than controlled greenhouse environments, this work has clearer and more immediate implications for farmers.

“That helps us understand the reality of the situation with weather or soil or other environmental factors interacting with biochar,” Ren says.

This group’s previous work has looked at how biochar impacts other factors like crop yield and greenhouse gas emissions.

“We want to have a complete understanding of biochar as an effective climate smart agricultural practice,” Ren says.

Biochar is particularly attractive to farmers in the Northeast, which has smaller operations than other parts of the country, like the Midwest. Biochar is still expensive for farmers to implement, making it difficult to apply at a larger scale.

“Although biochar is more expensive than other practices, they see the long-term benefits for the savings in water and nutrient inputs and the long-term carbon storage,” Ren says. “In the northeast region, our farmers and our growers have already shown interest.”

Further, biochar is most effective in climates with an average annual temperature below 59 degrees Fahrenheit and about 20 to 40 inches of rain, like Connecticut and other parts of the region.

Given this interest, the next steps in this research are to collaborate with local farmers to conduct pilot studies of biochar.

In addition to supporting field studies, the group is also using this work to develop models that can predict the long-term impacts of biochar on soil health and other key metrics.

The ultimate goal of this work is to develop a regional bioeconomy in which organic waste is collected, turned into biochar, and reused to grow more crops while keeping the soil healthy.

“We do want to collaborate with our field scientists, people with diverse backgrounds in climate and land use, and socioeconomics,” Ren says. “We want to propose an interdisciplinary program to promote region bioeconomy development.”

This work relates to CAHNR’s Strategic Vision area focused on Ensuring a Vibrant and Sustainable Agricultural Industry and Food Supply.

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