Physical Properties of Peats as Related to Degree of Decomposition

Abstract

Important physical characteristics, such as water retention, water yield coefficient, and hydraulic conductivity, vary greatly for representative northern Minnesota peat materials. The differences are related to the degree of decomposition, which largely determines the porosity and pore size distribution. Fiber content (> 0.1 mm) and bulk density are properties often measured to indicate the degree of decomposition of peat materials and are criteria used to distinguish fibric, hemic, and sapric peat types.Regression analyses showed a curvilinear relationship of water contents at saturation, 5 mbar, 0.1 bar, and 15 bar suctions, to fiber content (> 0.1 mm) and bulk density with coefficients of multiple determination (R2) ranging from .66 to .88. Regression analyses of the logarithm of hydraulic conductivity on fiber content (> 0.1 mm) and bulk density indicate a linear relationship (r2 = .54), although not as great due to the variability of hydraulic conductivity.Thus the classification of peat materials and organic soils based primarily on degree of decomposition as measured by fiber content and bulk density would relate significant information about their physical characteristics.

Soil water retention and carbon pools in tropical forested wetlands and marshes of the Gulf of Mexico

“…In most sites layers of both mineral and organic soils were found. The data published by Boelter (1969) and Brandyk et al (1996) for peat soils indicated that moisture retention characteristics were dependent on the degree of decomposition. In all cases, organic soils contained more water (Table 3), and a higher degree of humification results in finer particles and, consequently, organic soils had more water at any given tension (Kellner and Halldin 2002).…”

Humic substances in peat (Sumatra, Indonesia)

“…Given the difficulties (choice of extractant, neoformed products) encountered by the researchers working on European peat bogs [7][8][9] and after a number of laboratory tests, we decided to use the following protocols and to compare the results obtained with 2 g of test sample per 100 mL of solution (n × 5): extraction with sodium pyrophosphate at pH 10 for 16 h with stirring, extraction with 0.1 N sodium hydroxide (pH 12) for 16 h with stirring.…”

Ecological types of the eastern slope of the Wind River Range, Shoshone National Forest, Wyoming

“…Boelter (1969) provided regression equations for calculating water content from fiber content of organic soils. Equations were provided for 0.1 bar and 15 bar suctions (permanent wilting point).…”