喀斯特原生乔木林和次生林土壤呼吸研究

Study on the soil respiration under Karst primary forest and secondary forest

研究喀斯特森林土壤呼吸对探索陆地生态系统碳循环有重要意义.对喀斯特原生乔木林和次生林土壤呼吸速率的非生长季动态变化及对温度变化的响应和不同凋落物处理下土壤呼吸的变化进行了研究,结果表明：喀斯特次生林和原生乔木林土壤呼吸速率非生长季动态变化与土壤温度、林内温度变化总体一致;两演替群落土壤温度能解释95.1％ ～96.8％,91.3％ ～92.8％的土壤呼吸变化.去除、添加凋落物处理对土壤呼吸影响有显著差异（P＜0.05）,分别使土壤呼吸降低了21.29％～54.03％和增加了13.79％ ～98.41％.不同土壤深度土壤呼吸的Q1o值次生林为4.62～4.71、原生林为4.01～4.31.随着土壤深度的增加而增加,去除和添加凋落物处理引起土壤呼吸的Q10值不同,从大到小均表现为去除、对照、添加.两演替群落比较,土壤呼吸因小生境、森林植被不同而存在差异,次生林土壤呼吸速率高于原生乔木林,次生林呼吸速率与土壤温度的相关程度略高于原生乔木林,次生林土壤呼吸对温度的敏感性更强.

Research on Karst forest soil respiration is important to explore terrestrial ecosystem carbon cycle. Study on changes of the soil respiration rate in non-growing season,response to temperature changes and soil respiration changes under different litter processing in Karst different succession communities including secondary forest and primary forest. The results showed that the change of soil respiration rates of non-growing season were overall consistent with the temperature changes of soil and inside forest in Karst primary forest and secondary forest. The soil temperature of two succession community could explain 95. 1%-96. 8%,91. 3%-92. 8% of the variation in soil respiration,respectively.Removing and adding litter treatment influenced on soil respiration（ P〈 0. 05） significantly. Litter exclusion decreased soil respiration by 21. 29%-54. 03%,while litter addition increased soil respiration by 23. 79%-98. 41% compared with control. Different soil depth values of Q10 of soil respiration ranged from 4. 62 to 4. 71 in Karst secondary forest while ranged from 4. 01 to 4. 31 in primary forest,respectively. With the soil depth increasing,the Q10 value increased. Removing and adding litter treatment caused different Q10 values of soil respiration,which showed that the order of Q10 value of treatments was removing treatment control treatment adding treatment. Comparison of two successional communities,soil respiration varied due to different niche and forest vegetation. Soil respiration rate of the secondary forest was higher than that of the primary forest,relevance of secondary forest respiration rate and soil temperature was higher than that of the primary forest,the Q10 value in Karst secondary forest was higher than that in the primary forest.