摘要
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 14C fixed in roots was respired for Abee and 42% for Samson. This indicated that the turnover rate of root ^14C of Abee was higher than that of Samson. The percentage of water-soluble organic ^14C, active microbial ^14C and stable ^14C over the total fixed ^14C were not different between two barley cultivars. From the analysis of the model for two barley cultivars, the total ~4C transformed into different soil pools （excluding CO：-C and root C pools） for the two barley cultivars was similar （26% for Abee and 25% for Samson）, but the difference of ^14C remaining in soil between the two barley cultivars was mainly because of the difference of ^14C 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 studv.
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 14C fixed in roots was respired for Abee and 42% for Samson. This indicated that the turnover rate of root ^14C of Abee was higher than that of Samson. The percentage of water-soluble organic ^14C, active microbial ^14C and stable ^14C over the total fixed ^14C were not different between two barley cultivars. From the analysis of the model for two barley cultivars, the total ~4C transformed into different soil pools （excluding CO：-C and root C pools） for the two barley cultivars was similar （26% for Abee and 25% for Samson）, but the difference of ^14C remaining in soil between the two barley cultivars was mainly because of the difference of ^14C 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 studv.
