Effects Of Throughfall Exclusion And Nitrogen Addition On Soil Respiration Of Moso Bamboo(Phyllostachys Edulis) Forest In Southern Sichuan

Soil respiration is an important part of the carbon cycle process in terrestrial ecosystems.Affected by global climate change and environmental change.This study takes Moso Bamboo in southern Sichuan as the research object,through double-factor interaction test,four treatments:Ambient?A?,Throughfall reduction50%?D?,Nitrogen application10g N/m²·a?N?and Throughfall reduction and Nitrogen application?D×N?.Development of soil respiration and components?autotrophic respiration,heterotrophic respiration?,respond mechanism of soil respiration and components in bamboo forest to the throughfall reduction,nitrogen addition and its interaction.The main findings are as follows:?1?The temperature and humidity of 5cm soil in different treatment of bamboo forests changed significantly during the year.There was no significant change in soil temperature due to the throughfall reduction?D?and nitrogen addition?N?in forest,its interaction?D×N?does not affect soil temperature.Throughfall reduction in the forest reduced the soil moisture content from 44.95%to 32.98%in the sample area.The interaction between the throughfall reduction in the forest and the addition of nitrogen reduced the soil moisture content from47.16%to 34.19%?p<0.001?.Leaf area index and litter monthly input have obvious seasonal dynamic changes,there was no significant effect on leaf area index and litter input in forest area due to the throughfall reduction and nitrogen addition in forest area.?2?Soil respiration and components showed obvious seasonal dynamics.The trend of Rs,Ra,Rh and letter respiration rate changes is basically the same,peak of respiratory rate in summer,the lowest respiratory rate in winter.Double factor variance analysis shows that there was no significant effect on soil total respiration and autotrophic respiration due to the throughfall reduction in forest and nitrogen addition and interaction.Nitrogen addition significantly inhibited soil heterotrophic respiration rate?p<0.01?,the annual rate of heterotrophic respiration decreased by 0.33?mol CO₂·m^-2s^-1compared with the ambient,reduction of annual cumulative fluxes for heterotrophic respiration 528.77g CO₂·m^-2·a^-1.The contribution of autotrophic respiration to total respiration was significantly reduced by 13%due to nitrogen addition?3?Soil respiration and composition were significantly correlated with 5cm soil temperature?p<0.001?,5cm soil temperature can explain 50.1%-89.3%of soil respiration and component variation.Secondary correlation of soil respiration and composition with leaf area index and litter input.Ambient?A?,Throughfall reduction?D?and Throughfall reduction and Nitrogen application?D×N?total soil respiration was negatively related to soil moisture of 5cm?p<0.01?.Temperature Sensitivity(Q₁₀)of different respiratory components treated in the same treatment showed that autotrophic respiration was greater than heterotrophic respiration.