Abstract
Changes in soil organic carbon (SOC) stability may alter carbon release from the soil and, consequently, atmospheric CO2 concentration. The mean annual temperature (MAT) can change the soil physico-chemical characteristics and alter the quality and quantity of litter input into the soil that regulate SOC stability. However, the relationship between climate and SOC stability remains unclear. A 500-day incubation experiment was carried out on soils from an 11 °C-gradient mountainous system on Changbai Mountain in northeast China. Soil respiration during the incubation fitted well to a three-pool (labile, intermediate and stable) SOC decomposition model. A correlation analysis revealed that the MAT only influenced the labile carbon pool size and not the SOC stability. The intermediate carbon pool contributed dominantly to cumulative carbon release. The size of the intermediate pool was strongly related to the percentage of sand particle. The decomposition rate of the intermediate pool was negatively related to soil nitrogen availability. Because both soil texture and nitrogen availability are temperature independent, the stability of SOC was not associated with the MAT, but was heavily influenced by the intrinsic processes of SOC formation and the nutrient status.
Highlights
As CO2 exchange between soil carbon and atmospheric CO2 varies strongly along climate gradients[4,5], many scientists focus on whether there are enhanced response patterns in soil organic carbon (SOC) stability along increasing latitudinal or altitudinal gradients
The proportion of light fraction carbon in the total SOC ranged from 12.2% to 25.3% but was not correlated with the altitudinal gradient
Elevation was the key driver of variation in climate properties, the SOC decomposition during the 500-day incubation had no significant relationship with elevation on our study mountain
Summary
As CO2 exchange between soil carbon and atmospheric CO2 varies strongly along climate gradients[4,5], many scientists focus on whether there are enhanced response patterns in SOC stability along increasing latitudinal or altitudinal gradients. Numerous studies have implicated temperature as a primary controller of SOC stability by altering the quality and quantity of litter input into soil and soil physico-chemical characteristics[6,7,8]. Based on the heterogeneity of forest soils[22], the stability of SOC along climate gradients is likely associated with multiple factors resulting from interactions among physical, chemical and biological processes[10,21,23]. In order to determine the factors controlling SOC stability, it is essential to identify the substrate availability, i.e., the sizes of the carbon pools, acting as thermodynamic controls, and their corresponding decomposition rates, acting as kinetic controls[24,25,26]. By monitoring the accumulated C-CO2 released during soil incubation over a certain time period, both the capacity of mineralizable carbon and the decomposition rate can be evaluated according to a first-order kinetic model
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
