Journal article

Publication year: 2004

Pages: 1610-1615

Journal: Soil Science Society of America Journal

Volume number: 68

Issue number: 5

ISSN: 0361-5995

eISSN: 1435-0661

Open access status: Green

DOI Link: https://doi.org/10.2136/sssaj2004.1610

Publisher: Wiley

Abstract: 
The barometric process separation (BaPS) and N-15 dilution techniques were used to determine gross nitrification rates on the same soil cores from an old grassland soil. The BaPS-technique separates the O-2 consumption into that from nitrification and that from soil organic matter (SOM) respiration. The most sensitive parameter for the calculations via the BaPS technique is the respiratory quotient (RQ = DeltaCO(2)/DeltaO(2)) for SOM turnover (RQ(som)). Combining both methods (BaPS-N-15) allowed the determination of the RQ(som). The RQ value determined in such a way is adjusted for the influence of nitrification and denitrification, which are both characterized by totally different RQ values. The results for the grassland soil showed that 6 to 10% of O-2 was consumed by nitrification when incubated at 20 degreesC and 0.49 g H2O g(-1) soil. A set of BaPS measurements with the same soil at various temperature and moisture contents showed that up to 49% of the total O-2 consumption was due to nitrification. The calculated RQ(som) values via the BaPS-N-15 technique presented here are more closely associated with the overall SOM turnover than the usual net RQ reported in the literature. Furthermore, the RQ(som) value provides an overall indication of the decomposability and chemical characteristics of the respired organic material. Hence, it has the potential to serve as a single state index for SOM quality and therefore be a useful index for SOM turnover models based on substrate quality.

Harvard Citation style: Müller, C., Abbasi, M., Kammann, C., Clough, T., Sherlock, R., Stevens, R., et al. (2004) Soil respiratory quotient determined via barometric process separation combined with nitrogen-15 labeling, Soil Science Society of America Journal, 68(5), pp. 1610-1615. https://doi.org/10.2136/sssaj2004.1610

APA Citation style: Müller, C., Abbasi, M., Kammann, C., Clough, T., Sherlock, R., Stevens, R., & Jäger, H. (2004). Soil respiratory quotient determined via barometric process separation combined with nitrogen-15 labeling. Soil Science Society of America Journal. 68(5), 1610-1615. https://doi.org/10.2136/sssaj2004.1610