Nitrogen Speeds Soil Carbon Loss
University of Illinois researchers studied how nitrogen in crop residues contributes to loss of soil carbon as the residue decomposes. Their trials showed that any form of nitrogen, either present in the residue or applied as fertilizer, accelerated decomposition by microbes and produced more carbon dioxide. When the residue was fully decomposed, microbes turned to soil carbon, or stable organic matter. This led to greater overall carbon dioxide production from nitrogen-fertilized residue, as well as a long-term loss of soil organic matter. The researchers plan to conduct similar testing in other soil types to see if they perform the same way.