Opposing response of biogenic volatile organic compound and CO2 emissions to nitrogen addition during decomposition of two litter species

Aims

Biogenic volatile organic compound (BVOC) emissions from leaf litter play an important role in forest carbon (C) cycles. This study investigated the combined effects of nitrogen (N) addition and leaf litter species on BVOC emissions and the relative contribution of C emissions in the form of BVOCs to CO₂ emissions.

Methods

An incubation experiment was conducted using two levels of N addition and two leaf litter species (Schima superba and Cunninghamia lanceolata). We measured BVOC and CO₂ emissions and litter chemical properties during litter decomposition.

Results

Total BVOC-C emitted from two leaf litter species accounted for 0.19%–0.47% of CO₂-C emissions. N addition decreased the total BVOC emissions, but increased CO₂ emissions from the decomposition of both litter species. N addition increased total N and soluble sugar contents of leaf litter but reduced the starch content and C/N ratio. Following N addition, the fluxes of most BVOC types were positively correlated with starch and nonstructural carbohydrate contents of S. superba leaf litter and with the C/N ratio of C. lanceolata leaf litter. In addition, the total BVOC and CO₂ emissions from S. superba leaf litter were higher than those from C. lanceolata. Corresponding, S. superba leaf litter had higher N and soluble sugar contents but lower C/N ratio and starch content than C. lanceolata leaf litter.

Conclusion

N addition inhibited BVOC emissions and promoted CO₂ emissions during leaf litter decomposition. Leaf litter with a high labile substrate content is likely to release more BVOCs during the early-stage of litter decomposition.