Longer, more diverse rotations of crops fertilized with livestock manure have many environmental benefits, but carbon sequestration isn’t one of them, according to a new study led by Iowa State University researchers.
Longer, more diverse rotations of crops fertilized with livestock manure have many environmental benefits, but carbon sequestration isn’t one of them, according to a new study led by Iowa State University researchers.
The findings, published this month in Nature Sustainability, counter long-standing assumptions and could have implications for various carbon-market initiatives designed to help mitigate climate change, said Wenjuan Huang, assistant professor of ecology, evolution and organismal biology.
“In a diversified cropping system, there’s more carbon input. So we have figured there would be more carbon stored in the soil. But actually, carbon levels in the soil didn’t change over 20 years, though these regenerative management practices are still valuable in other ways,” said Huang, one of the study’s lead co-authors.
The study is based on data collected from the ongoing field trial at Iowa State’s Marsden Farm just east of Boone, which since 2001 has compared a traditional two-year corn-soybean rotation to three- and four-year systems that mix in a year or two of alfalfa, clover or oats and replace most of the synthetic nitrogen fertilizer for corn with cattle manure.
Read more at Iowa State University
Image: Oats growing near plots of corn at Iowa State University's Marsden Farm, where researchers have studied long-term rotations of crops since 2001. Photo by David Sunberg/Iowa State University.
