Iowa State University researchers may have discovered a more environmentally-friendly fertilizer that could avoid the problems other fertilizers have with washing nutrients into waterways.
The researchers were using heat and chemical treatments to produce sugars, oil and a charcoal called “biochar," and found that the biochar product kind of acts like a medicine that takes longer to go through the body, producing fewer side effects in a patient.
“The notion is you want it to be released over the course of a day rather than over the course of a few minutes,” said Robert Brown, the director of ISU’s Bioeconomy Institute.
Brown and Santanu Bakshi, an assistant scientist at the Bioeconomy Institute, found the biochar acts as a sponge for phosphorous.
As a fertilizer, it could basically absorb phosphorous from runoff and release it very slowly so a crop could make use of it.
“Even after it’s been adsorbed, it retains on that charcoal and only very slowly is released – released at a rate more commensurate with what the plant needs as a nutrient rather than it simply being all washed down the stream,” Brown said.
Bakshi said if that’s used in the field and there’s a lot of rain one day, “there would be little loss of the phosphorous or no loss at all” compared to more standard fertilizers that could wash out from soil.
“We don’t want to wash away all the fertilizer from the field after a heavy rain shower,” Bakshi said. “This material will stay on the soil for a long period of time and the plant can utilize this phosphorus for a long period of time," instead of adding conventional fertilizers too often.
Farmers could have more flexibility in planting and fertilizing, Brown said, since nutrients could be released over a growing season rather than a quick shower. They would potentially be applying less fertilizer over time since less would be washed away by rain.
The researchers are looking into whether biochar can also capture nitrogen.
Ultimately, Brown and Bakshi say they would like to scale up their research in fall 2020 and bring the work that’s being done in a lab into the field. They would have to generate a lot more biochar – as much as 10 tons of the material per day – to work with in field testing, they said.