Bernardo del Campo, a Ph.D. student in mechanical engineering at Iowa State University, is collaborating with a German team to better understand the benefits of biochar as a soil additive. Specifically, the group is studying the ability of biochar to retain nitrates and yet make them available to plants. Biochar is made from the pyrolysis (heating in the absence of oxygen) of biomass.
“What we’re seeing is that current methods that measure nitrate availability to plants when on amended char plots are not very accurate,” said del Campo, who is affiliated with the Bioeconomy Institute. The team is using isotopes to track nitrogen in plants and soil in both field studies as well as in greenhouse tests.
Retaining nitrates in the soil has a double benefit. First, less fertilizer is needed if the nitrates are kept in the soils and made available to crops. “Some 40 to 50 percent of the nitrogen applied to fields is lost to the air or to the water,” del Campo explained. Second, retaining nitrates in the soil keeps them out of the community water systems, a growing problem for agriculturally-intensive areas. Del Campo notes that the Des Moines, Iowa, water department has the world’s largest nitrate removal system for just this reason.
The researchers are also looking at the differences between recently produced and “aged” biochar. After few years of being in contact with the soil the chemical properties and adsorption behavior of char significantly changes. When char is mixed with compost a similar process happens but much faster, and this is yet to be fully understood. “Once you compost biochar, it changes its chemical properties but also, the microbial community associated with,” del Campo said. The scientists believe the combination of compost and biochar could significantly reduce nitrate leaching from agriculture and retain it for next year’s crop. The researchers hope to publish a paper on their findings by the end of 2014.
Germany Gets Green Talent
In May 2014, del Campo went to Giessen, Germany, for two weeks to work on the project. He plans to return at the end of the summer to continue the research. The lead researcher on the project is Claudia Kammann a postdoctoral researcher at Justus-Liebig University. “She has been working in biochar a long time and is interested in the environmental benefits of biochar,” del Campo said.
Del Campo’s work on the project is funded as a result of his receiving a “Green Talents” award in 2012. This award, given by the German Federal Ministry of Education and Research (BMBF) is called the “International Forum for High Potentials in Sustainable Development.” Del Campo and the other winners toured German research institutions, discussed their ideas with German experts, and collaborated on research.