Fiber content and degree of decomposition in peats: review of national methods
1992
Malterer, T.J. | Verry, E.S. | Erjavec, J.
Fiber content and degree of decomposition are important physical and chemical peat characteristics. However, there are no internationally accepted methods for their determination. We review selected national methods that measure degree of decomposition and fiber content, and evaluate their precision and their capacity to distinguish between classes of peat. We also relate one national method to another using scaled-variable regression equations. The von Post humification method, a European field test, was used in the identification and sample collection of 10 humification (decompositional) peat classes, from sphagnum, herbaceous, and humus peat types. Subsequent statistical analyses of the samples revealed that only eight classes were significantly different. The USSR centrifugation method successfully identified all eight classes, while the ASTM fiber method successfully identified four of the classes, the USDA fiber methods identified three, four, or five classes, and the USDA pyrophosphate method identified three of the classes. These analyses indicate that the USSR centrifugation laboratory method and the von Post humification field method separate more classes of peat with greater precision than the ASTM, several USDA fiber volume, and USDA pyrophosphate methods. However, similar tests on woody peats and tropical peats are needed to test the universal acceptability of the USSR centrifugation and the von Post humification methods. Predictive regressions between methods had R2 values from 0.690 to 0.998 and CVs form 4.8 to 45.3%. Thirty-eight percent of the between-method regressions are parabolic, 43% linear, and the remainder cubic.
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