Estimating carbon storage potential of fallow weeds in rice cropping systems

Abstract Weeds occurred during the fallow season can well perform the function of carbon (C) storage due to receiving little human disturbance. This study aimed to evaluate the C storage potential of fallow weeds in rice cropping systems. A six-region, two-year on-farm investigation and a three-year tillage experiment were conducted to estimate C storage in fallow weeds in rice cropping systems. The on-farm investigation showed that the average mean C storage in fallow weeds across six regions and two years reached 112 g m–2. The tillage experiment indicated that no-tillage practices increased C storage in fallow weeds by 80% on average as compared with conventional tillage. The results of this study not only contribute to an understanding of C storage potential of fallow weeds in rice cropping systems, but also provide a reference for including fallow weeds in the estimation of vegetative C sink. Further investigations are required to determine the effect of C input from fallow weeds on C balance of rice paddies in order to comprehensively evaluate the role of fallow weeds in C cycling in rice cropping systems.