Leaching is the dominant route for soil organic carbon lateral transport under crop straw addition on sloping croplands

摘要

Few field data sets are available that systematically measure soil organic carbon (SOC) transport via surface runoff, leaching and soil erosion under crop straw applications. Therefore, organic carbon (C) loss fluxes via the three routes were simultaneously observed from 2010 to 2012 based on a crop straw addition experiment. This study included three treatments: CK (no fertilizer); RSD (crop straw addition) and RSDNPK (crop straw addition combined with mineral fertilizers). As compared with CK treatment, annual dissolved organic C (DOC) loss caused by surface runoff under RSD and RSDNPK treatments decreased significantly ( P 2 /sup). DOC leaching accounted for 70% and 77% of SOC transport under RSD and RSDNPK treatments. These results clearly show that leaching is the dominant route of SOC lateral transport under crop straw applications. Therefore, reduced DOC leaching is the crucial link to enhance SOC sequestration when crop straw is returned to sloping croplands.