Field measures of the contribution of root respiration to soil respiration in an alder and cypress mixed plantation by two methods: trenching method and root biomass regression method

The contribution of root respiration to total soil respiration is one of the most interesting, important, and methodologically complicated problems in the study of the carbon budget in soils. A trenching method and a root biomass regression method were used to determine the contribution of root respiration to total soil respiration in a subtropical forest ecosystem. The average root respiration contributions were 37.15% with the range of 13.04-51.23% by trenching method and 31.80% with the range of 10.64-56.10% by root biomass regression method from August 2005 to July 2006. In growing season, the contributions of root respiration were 47.25 and 43.53% estimated by trenching method and root biomass regression method, respectively. There was no significant difference between the monthly attributions of root respiration to soil respiration estimated by two methods. Our results showed that trenching and root biomass regression methods were both suitable to estimate the root respiration in this forest.