Greenhouse Gas Cycling and Ecosystem Services: Organic Amendments Under Rice-Rice-Rice Cropping System and Net Ecosystem Carbon Status

Paddy field is the main source of carbon (C) loss as greenhouse gas (GHGs) during rice cultivation, but the impact is generally analyzed based on mono rice cropping without considering three seasons in a year. Moreover, the influences of cow dung (CD), vermicompost (VC), and recommended sole chemical fertilizer (RCF) on CH4-C and CO2-C emission patterns and net ecosystem C status are not well documented in Asian regions depending on irrigated dry season (Boro)–pre-monsoon (Aus)–monsoon (T. Aman) rice cultures. In this study, the effect of CD, VC, and sole RCF application on CH4-C and CO2-C emissions was investigated using closed static chamber technique. The amendment with VC showed the lowest CH4-C and CO2-C emissions than CD treatment, and it significantly increased total C input by about 4–10% compared to CD under triple rice cropping system. The net C status was significantly improved by about 14–20% under VC compared to CD and sole RCF. There was also significant difference of rice yield between CD and VC amendments. In conclusion, soil amendment with VC could be a very useful tool for increasing rice productivity as well as enhancing net ecosystem C status under Boro–T. Aman–Aus cropping system.