Drying and substrate concentrations interact to inhibit decomposition of carbon substrates added to combusted Inceptisols from a boreal forest

摘要: Climate change is expected to alter the mechanisms controlling soil organic matter (SOM) stabilization. Under climate change, warming and drying could affect enzymatic that control SOM turnover dependence on substrate concentration. Here, we used a greenhouse manipulation in mature boreal forest test two specific hypotheses: (1) Rates of decomposition decline at lower concentrations, (2) reductions moisture disproportionately constrain degradation low-concentration substrates. Using constructed cores, measured rates polymeric substrates, starch cellulose, as well enzyme activities associated with these The increased temperature by 0.8 °C reduced cores up 90 %. We rejected our first hypothesis, rate did not decrease declining concentration under conditions, but find support for hypothesis two: Drying led starch. observed threefold reduction respiration bulk soils greenhouses over 4-month period, C losses from vary among treatments. Activities enzymes degrade cellulose were elevated treatments, which may have compensated constraints common (i.e., cellulose) cores. This study confirms can be concentration-dependent suggests effects reduce well-drained lacking permafrost.