Contribution of root respiration to soil respiration in a rape (Brassica campestris L.) field in Southwest China

This study aimed to separate the respective contributions of root and microbial respiration to soil respiration in a rape field in Southwest China. The soil respiration was measured with a closed chamber technique and a regression method was used to apportion root and microbial respiration. Microbial and root respiration ranged from 70.67 to 183.77 mg CO2/m 2/h and 21.99 to 193.09 mg CO2/m 2/h, averaged 127.16 and 116.66 mg CO2/m 2/h during the rape growing season, respectively. Root respiration coefficient ranged from 0.41 to 5.39 mg C-CO2/g C/h and was negatively correlated with root/shoot ratio, aboveground and belowground biomass, but positively correlated with root N content. The contribution of root respiration to soil respiration averaged 44.2%, ranging from 14.5% to 62.62%.