Straw Return Locks More Carbon in Paddy Soils

A research team has shown that returning rice straw to paddy fields increases soil organic carbon by strengthening soil aggregates and promoting stable chemical bonds between carbon and iron oxides. Drawing on an 11-year field experiment, the researchers identified two complementary carbon-storage mechanisms: physical protection inside aggregates and chemical stabilization through iron-carbon associations. The findings clarify how straw incorporation supports long-term carbon sequestration and could guide agricultural practices that improve soil fertility, recycle crop residues, and reduce the climate footprint of intensive rice production.