| Soil respiration rate and its temperature sensitivity(Q10)are important parameters for simulating and predicting soil organic carbon storage dynamics under future climate change.In this study,we studied the elevation variation and environmental control factors of soil respiration and temperature sensitivity in Shennongjia and Wuyi Mountain Nature Reserve at depths of 0～20 cm and 20～40 cm.The results showed as follows:（1）Soil respiration was significantly affected by temperature and altitude gradient（p<0.05）.At the same altitude gradient,soil respiration increased with the increase of temperature.Under the same temperature,the soil respiration at 1892 m in Shennongjia nature reserve was significantly higher than that at other elevations,reaching 4.55-10.30μg·g-1·h-1.The soil respiration at 1364 m in Wuyi Mountain Nature Reserve was significantly higher than that at other elevations.The values are 4.07-9.35μg·g-1·h-1.In terms of soil respiration temperature sensitivity(Q10),Q10was significantly different at different altitudes（p<0.05）.Q10in Shennongjia nature reserve increased with the elevation gradient,while Q10in Wuyi Mountain Nature Reserve decreased first and then increased with the elevation.（2）Soil respiration was significantly different at different depths under different elevation gradients（p<0.05）,and soil respiration at 20～40 cm was significantly higher than that at 0～20 cm.In Shennongjia nature reserve,soil respiration of 0～20 cm and 20～40 cm showed the same trend,and increased with the increase of elevation gradient.In Wuyi Mountain Nature Reserve,soil respiration at 20～40 cm increased first and then decreased with the increase of elevation gradient,while soil respiration at 0～20 cm increased with the increase of elevation gradient.According to the Q10obtained by fitting each culture temperature,we found that the soil Q10of0～20 cm in Shennongjia and Wuyi Mountain Nature Reserve was significantly larger than that of 20～40 cm.（3）In Shennongjia nature reserve and Wuyi Mountain Nature Reserve,soil respiration and temperature sensitivity of different vegetation types were significantly different（p<0.05）.In Shennongjia nature reserve,soil respiration was in the order of coniferous and broad-leaved mixed forest>evergreen broad-leaved mixed forest>evergreen broad-leaved mixed forest.Soil respiration was the highest in coniferous and broad-leaved mixed forest(4.55-10.30μg·g-1·h-1),and Q10was in the order of coniferous and broad-leaved mixed forest>evergreen broad-leaved mixed forest>evergreen broad-leaved forest,and the minimum value was 1.67 in evergreen broad-leaved forest.In Wuyi Mountain Nature Reserve,soil respiration was in the order of cunninghamia lanceolata forest>coniferous and broad-leaved mixed forest>evergreen broad-leaved mixed forest.Soil respiration was 3.99-8.98μg·g-1·h-1in cunninghamia lanceolata forest,and its Q10value was in the order of evergreen broad-leaved mixed forest>coniferous and broad-leaved mixed forest>Cunninghamia lanceolata forest.The Q10value of cunninghamia lanceolata forest was 1.70.（4）There were significant differences in soil physical and chemical properties in Shennongjia and Wuyi Mountain Nature Reserve under different elevation gradients（p<0.05）.According to the correlation analysis results,soil respiration and Q10were significantly correlated with some soil physical and chemical indexes in Shennongjia area,while soil respiration was significantly correlated with soil physical and chemical properties in Wuyi Mountain Nature Reserve,but Q10was not significantly correlated with soil physical and chemical properties.By the above results can be concluded that:along with the change of altitude and soil respiration and temperature sensitivity of soil depth,vegetation type and related to environmental factors such as soil physical and chemical properties,and major environmental control factors in two different soil layer,suggests that in the context of climate change,soil organic carbon in elevation and soil depth may not show consistent trends. |
