The researchers studied different ways of returning rice straw to the soil during the wheat-growing season to see how it affected methane emissions during the following rice-growing season. They found that incorporating rice straw into the topsoil reduced methane emissions compared to mulching it on the field surface. Burning rice straw in-situ did not significantly affect methane emissions. Incorporating rice straw into the topsoil also increased soil carbon and nitrogen content without impacting rice yield. This suggests that incorporating rice straw into the topsoil before planting wheat can help reduce methane emissions in the following rice-growing season and improve soil quality.