Effects Of Corn Straw And Biochar Addition On The Stimulation Effect Of Particulate And Mineral-bound Organic Carbo

Soil carbon pool is an important part of carbon cycle in terrestrial ecosystem,and its slight fluctuation has great influence on atmospheric carbon dioxide concentration.Priming effect（PE）changes the decomposition rate of soil organic matter,which plays an important role in the turnover of soil organic matter and global climate change.However,the existing studies assumed that the excitation effect of different soil carbon components was consistent,which ignored the influence of soil carbon component differences on the priming effects.Therefore,the Particulate organic carbon（POC）,Mineral-associated organic carbon（MAOC）obtained by the physical grouping method are obtained.We added equal-carbon straw and biochar at 22℃ and 32℃ for 60 days of laboratory culture experiment.We regularly measured soil respiration and carbon isotope values to explore the priming effects of different soil carbon components and their temperature sensitivity.The main conclusions of this study are as follows:（1）The cumulative mineralization of soil organic carbon of straw was greater than that of biochar.The cumulative mineralization of soil organic carbon of mineral-associated organic carbon>particulate organic carbon.（2）The priming effect of straw was higher than biochar of the three soils.The priming effect of the three soils induced by straw are all positive and the priming effect of the three soils induced by biochar are all negative.（3）The particulate organic carbon have higher PE than mineral-associated organic carbon,indicating that particulate organic carbon was more sensitive.（4）The temperature sensitivity of soil organic carbon decomposition after adding straw or biochar decreased,but it was still sensitive(Q₁₀>1).（5）The temperature sensitivity of the priming effect of biochar addition was Q ₁₀<1,while that of the other treatments was Q₁₀>1.The temperature sensitivity of mineral-associated organic carbon was higher than particulate organic carbon.In conclusion,priming effects of different soil carbon fractions were different,which was related to exogenous additives.The response mechanism of differe nt soil carbon fractions to exogenous additives should be studied,so as to provide data for accurate estimation of terrestrial ecosystem carbon cycle and its response to climate change.