Simulation of in situ Root Decomposition of Two Barley Cultivars

Abstract Root C and root-released C are closely related to soil organic matter content and mechanistic simulation modeling has proven to be useful for studying root and soil organic C dynamics in plant-soil ecosystems. A computer model was designed in this study to simulate the dynamics of root C and root released C decomposition in situ and the dynamics of different forms of C in soil under two barley cultivars (Abee and Samson). The results showed that on the 15th day, about 48% of the total 14 C fixed in roots was respired for Abee and 42% for Samson. This indicated that the turnover rate of root 14 C of Abee was higher than that of Samson. The percentage of water-soluble organic 14 C, active microbial 14 C and stable 14 C over the total fixed 14 C were not different between two barley cultivars. From the analysis of the model for two barley cultivars, the total 14 C transformed into different soil pools (excluding CO 2 -C and root C pools) for the two barley cultivars was similar (26% for Abee and 25% for Samson), but the difference of 14 C remaining in soil between the two barley cultivars was mainly because of the difference of 14 C remaining in roots which have not been yet decomposed. Some of the information which could not be measured in the laboratory conditions was obtained in this study.