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Shortcomings in the Commercialized Barometric Process Separation Measuring System
Author(s) -
Ingwersen Joachim,
Schwarz Ulrich,
Stange Claus Florian,
Ju Xiaotang,
Streck Thilo
Publication year - 2008
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2007.0092
Subject(s) - nitrification , soil water , carbonate , environmental science , chemistry , environmental chemistry , soil science , nitrogen , organic chemistry
In a growing number of studies, the barometric process separation (BaPS) method has been applied for measuring gross nitrification rates in soil. In 2000, the company Umweltanalytische Mess‐Systeme (UMS) GmbH (Munich, Germany) presented the first and only commercially available automatic BaPS measuring system. In an ongoing project, we have used the UMS BaPS system to measure gross nitrification rates in two alkaline agricultural soils. During data evaluation, we came across certain shortcomings in the UMS data evaluation routine. We identified three problems: (i) a unit error in the calculation of the carbonate equilibrium, (ii) an erroneous calculation when the respiration quotient is unequal to unity, and (iii) an inappropriate procedure for handling a negative rate of N gases produced by denitrification (ΔN x O y ). Particularly the error in calculating the carbonate equilibrium caused a significant overestimation of the gross nitrification rate at pH values >6. A literature review showed that the BaPS method works well in acidic to weakly acidic soils. For soils with higher pH values, its performance remains unclear. More research is needed to test the applicability of the BaPS method in neutral and alkaline soils.