长白山岳桦-暗针叶林过渡带根系呼吸对土壤总呼吸的贡献

Total and root-severed soil respiration rates for five plots set up 50 m apart in a Betula ermanii Cham.-dark coniferous forest ecotone on a north-facing slope of the Changbai Mountains, China, were measured to evaluate the seasonal variations of soil respiration, to assess the effect of soil temperature and water content on soil respiration, and to estimate the relative contributions of root respiration to the total soil respiration. PVC cylinders in each of 5 forest types of a B. ermanii-dark coniferous forest ecotone were used to measure soil respirations both inside and outside of the cylinders. The contribution of roots to the total soil respiration rates ranged from 12.5% to 54.6%. The mean contribution of roots for the different plots varied with the season, increasing from 32.5% on June 26 to 36.6% on August 3 and to 41.8% on October 14.In addition, there existed a significant （P 〈 0.01） logarithmic relationship between total soil respiration rate and soil temperature at 5 cm soil depth. Also, a similar trend was observed for the soil respiration and soil water content at the surface （0-5 cm） during the same period of time.

Contribution of root respiration to total soil respiration in a Betula ermanii-dark coniferous forest ecotone of the Changbai Mountains, China

Total and root-severed soil respiration rates forfiveplots set up 50 m apart in a Betula ermanii Cham.-dark coniferous forest ecotone on a north-facing slope of the Changbai Mountains, China, were measured to evaluate the seasonal variations of soil respiration, to assess the effect of soil temperature and water content on soil respiration, and to estimate the relative contributions of root respiration to the total soil respiration. PVC cylinders in each of 5 forest types of a B. ermanii-dark coniferous forest ecotone of roots to the total soil were used to measure soil respirations both inside and outside of the cylinders. The contribution respiration rates ranged from 12.5% to 54.6%. The mean contribution of roots plots varied with the season, increasing from 32.5% on June 26 to 36.6% on August 3 and to 41.8% on October 14. In addition, there existed a signif cant (P <0.01) logarithmic relationship between total soil respiration rate and soil temperature at 5 cm soil depth.Also, a similar trend was observed for the soil respiration and soil water content at the surface (0-5 cm) during the same period of time.