Exploring the Impact of Biochar and Dissolved Organic Carbon on Soil CO2 Emissions in Subtropical China
A study in subtropical China found that biochar increases soil CO2 emissions in degraded lands by enhancing microbial activity, while it reduces emissions in fertile forest soils by suppressing it. The effect of dissolved organic carbon on emissions diminishes with vegetation restoration.
Researchers from Fujian Agriculture and Forestry University and other Chinese institutions have conducted a pivotal study on how biochar and dissolved organic carbon (DOM) influence soil CO2 emissions across different stages of vegetation restoration in subtropical China. The study, situated in Changting County, Fujian Province, scrutinized soil from three stages of vegetation: degraded land, plantation forest, and secondary natural forest.
The findings indicate a varied response of soil CO2 emissions to biochar and DOM addition, contingent on the stage of vegetation restoration and soil fertility. In degraded soils, the addition of biochar escalated CO2 emissions, enhanced soil pH, and stimulated activities of enzymes like phenol oxidase and peroxidase, which are closely linked with CO2 release. This suggests that in nutrient-poor soils, biochar might actually promote CO2 emissions by boosting microbial activity.
Conversely, in more fertile soils from plantation forests and secondary natural forests, biochar application markedly reduced CO2 emissions. This reduction was associated with a decrease in enzymes that catalyze biomass degradation, thus suggesting a suppression of microbial activity related to CO2 production. Moreover, the study revealed that the positive effects of DOM on CO2 emissions diminished as the vegetation restoration progressed.
These insights are crucial as they illustrate biochar’s dual potential to either decrease or increase soil CO2 emissions based on the ecological context, highlighting the importance of tailored biochar application strategies in forest ecosystems. This knowledge aids in optimizing biochar use for enhancing soil carbon storage and reducing greenhouse gas emissions, essential components in combating climate change and managing forest carbon cycles effectively.
