Soil respiratory quotient determined via barometric process separation combined with nitrogen-15 labeling
Soil respiratory quotient determined via barometric process separation combined with nitrogen-15 labeling
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DOI：
10.2136/sssaj2004.1610
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发表时间：
2004-09-01
影响因子：
2.9
通讯作者：
Jäger, HJ
中科院分区：
文献类型：
--
作者：
Müller, C;Abbasi, MK;Jäger, HJ
采用气压过程分离法（BaPS）和N-15稀释法测定了一个老草地土壤的总硝化速率。BaPS技术将O-2消耗分为硝化作用和土壤有机质（SOM）呼吸作用。通过BaPS技术计算的最敏感参数是SOM周转（RQ（som））的呼吸商（RQ = DeltaCO（2）/DeltaO（2））。结合两种方法（BaPS-N-15）可以测定RQ（som）。以这种方式确定的RQ值针对硝化作用和反硝化作用的影响进行调节，硝化作用和反硝化作用都以完全不同的RQ值为特征。结果表明，在20 ℃和0.49 g H_2O g（-1）土壤条件下培养时，6 ~ 10%的O-2被硝化作用消耗。一组BaPS测量相同的土壤在不同的温度和水分含量表明，高达49%的总O-2消耗是由于硝化作用。通过这里提出的BaPS-N-15技术计算的RQ（SOM）值与文献中报道的通常的净RQ相比，与总体SOM营业额更密切相关。此外，RQ（som）值提供了呼吸有机材料的可分解性和化学特性的总体指示。因此，它有可能作为一个单一的状态指数的SOM质量，因此是一个有用的指数SOM营业额模型的基础上基板质量。
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.