Differences In Sensitivity Of Forest Soil Respiration Temperature And Its Mechanism In Different Latitudes

The forest soil carbon pool accounts for 73%of the terrestrial ecosystem soil carbon pool,and its small changes will have a huge impact on atmospheric CO₂ concentration and the global carbon cycle.Soil respiration is a key process of soil carbon cycle.Its temperature sensitivity(Q₁₀)can describe the response of soil respiration to temperature rise,and it is one of the important evaluation indicators of global warming and soil carbon cycle feedback.Studying the soil respiration temperature sensitivity and its driving factors in China's forest ecosystems has important research significance for accurately assessing the response of Chinese forest carbon cycle to global climate change.Therefore,this study takes the natural and artificial forest soils of the South-Northern forest transect of China as the research object,and uses indoor culture methods to study the effects of different culture temperatures on soil respiration rate of major forest types in China,and natural forest and plantation soil respiration.The dimensional difference of temperature sensitivity and the driving mechanism,in order to better understand the heterotrophic respiration rate and temperature sensitivity coefficient of forest soil in different latitudes in China.The main findings of this study are as follows:?1?Under different culture temperature conditions,there were significant differences in soil respiration rate and soil respiration accumulation between natural forest and plantation,and there were significant interactions between forest type and plot dimension.The dimension significantly affected the respiration rate and accumulation of forest soil.The soil respiration decreased with the decrease of the dimension,while the soil respiration rate of natural forest decreased continuously,but the soil respiration rate and accumulation of the natural forest in the north subtropical zone?Xinyang?were significant.Other dimensions of the region take forest soil respiration.In addition,with the increase of culture temperature,the heterotrophic respiration rate of forest soils in different dimensions showed a significant increase trend.?2?Forest type,latitude and forest type×latitude interaction significantly affected the content of ammonium nitrogen,nitrate nitrogen,DOC,DON and microbial biomass carbon in indoor culture soil.The soil respiration rate of natural forest was significantly positively correlated with soil DOC and ammonium nitrogen content,but negatively correlated with soil nitrate nitrogen content.The soil respiration rate of plantation was significantly positively correlated with DOC and MBC,and soil nitrate The nitrogen content was significantly negatively correlated.?3?The Q₁₀ value of heterotrophic respiration temperature sensitivity in forest soils in China ranged from 1.21 to 1.91,and the Q₁₀ of heterotrophic respiration temperature in forests in temperate regions was higher than that in subtropical and tropical regions.In addition,the soil respiration rate Q₁₀0 of natural forests and plantations in different dimensions is different.In the cold temperate zone,the middle temperate zone and the tropical zone,the natural forest Q₁₀ is lower than the plantation forest,while the subtropical zone natural forest soil Q₁₀ is higher than the plantation forest.In addition,forest types and dimensions significantly affect soil SOC,total N,total P,ammonium nitrogen,nitrate nitrogen,and soil available P content.?4?Soil heterotrophic respiration temperature sensitivity Q₁₀ showed a significant negative correlation with annual mean temperature?MAT?and annual mean precipitation?MAP?.There was a significant positive correlation between soil Q₁₀0 and soil total N and total P content,but a significant negative correlation with soil nitrate nitrogen content.However,the Q₁₀ values of natural and artificial forest soils have different responses to climate and soil nutrient factors,and the correlation between soil Q₁₀0 and climate and soil factors is more significant.