土壤温度和水分对长白山不同森林类型土壤呼吸的影响

Effects of soil temperature and moisture on soil respiration in different forest types in Changbai Mountain.

在实验室条件下 ,将不同含水量的 3种森林类型的土柱分别置于 0、5、1 5、2 5和 35℃条件下 ,进行土壤呼吸测定 .结果表明 ,在 0～ 35℃范围内 ,土壤呼吸速率与温度呈正相关 .在一定含水量范围内 (0 .2 1～ 0 .37kg·kg- 1 ) ,土壤呼吸随含水量的增加而升高 ,当含水量超出该范围 ,土壤呼吸速率则随含水量的变化而降低 .土壤温度和水分对土壤呼吸作用存在明显的交互作用 .不同森林类型土壤呼吸作用强弱存在显著差异 ,大小顺序为阔叶红松林 >岳桦林 >云冷杉暗针叶林 .阔叶红松林土壤呼吸作用的最佳条件是土壤温度 35℃、含水量 0 .37kg·kg- 1 ;云冷杉暗针叶林下的山地棕色针叶林土壤呼吸作用的最佳条件是 2 5℃、0 .2 1kg·kg- 1 ;岳桦林土壤呼吸作用的最佳条件是 35℃、含水量 0 .37kg·kg- 1 .但是 ,由于长白山阔叶红松林、云冷杉林和岳桦林处在不同的海拔带上 ,同期不同森林类型土壤温度各不相同 ,相差 4～ 5℃ ,所以野外所测的同期山地棕色针叶林土呼吸速率应低于暗棕色森林土呼吸速率 。

The effects of soil temperature (0, 5, 15, 25, 35 ℃) and water content on soil respiration in three forest types in Changbai Mountain were evaluated in laboratory condition. The results indicated that the soil respiration rate was positively correlated to soil temperature from 0 to 35 ℃ and it increased with soil water content from 0.21 to 0.37 kg·kg -1 . The soil respiration rate decreased with soil water content when water content was over the range. The result suggested the interactive effects of temperature and water content on soil respiration. There were significant differences in soil respiration among the various forest types and the highest was in broad leaf Korean pine forest, then in erman's birch forest, and it was the lowest in dark coniferous forest. The optimal condition for soil respiration in broad leaved Korean pine forest was at 35 ℃ under 0.37 kg·kg -1 water content, and it was at 25 ℃ under 0.21 kg·kg -1 in dark coniferous forest and at 35 ℃ under 0.37 kg·kg -1 water content in erman's birch forest. Because the forests of broad leaf Korean pine, dark coniferous and erman's birch are located at various altitudes, the soil temperatures had 4～5 ℃ variation in different forest types during the same period. The soil respiration rates measured in brown pine mountain soil were lower than those in dark brown forest and they were higher in mountain grass forest soil than those in brown pine mountain soil.