Background and aims: Rhizodeposition of plants in the most uncertain component of the carbon (C) cycle. By existing approaches the amount of rhizodeposition can only roughly be estimated since its persistence in soil is very short compared to other organic C pools. We suggest an approach to quantify rhizodeposition at the field scale by assuming a constant ratio between rhyzodeposited-C to root-C. Methods: Maize plants were pulse-labeled with 14CO2 under controlled conditions and the soil 14CO2 efflux was separated into root and rhizomicrobial respiration. The latter and 14C activity ramaining in the soil corresponded to total rhizodeposition. By relating rhizodeposited-14C to root-14C a rhizodeposition-to- root ratio of 0.56 was calculated. This ratio was applied to the root biomass C measured in the field to estimate rhizodeposition under field conditions. Results: Maize allocated 298 kg C ha-1 as root-C and 166 kg c ha-1 as rhizodeposited-C belowground, 50;of which were recorvered in the upper 10cm. The fate of rhizodeposits was estimated based on the 14C data, which showed that 62;of total rhizodeposition was mineralized within 16 days, 7;and 0.3;was incorporated into microbial biomass and DOC, respectively, and 31;was recovered in the soil. Conclusion: We conclude that the present approach allows for an improved estimation of total rhizodeposition, since it accounts not only for the fraction of rhizodeposits remaining in the soil, but also for that decomposed by microorganisms and released from the soil as CO2.