Water Storage Characteristics of Several Peats in situ

Abstract

AbstractWater storage characteristics of the various horizons in a northern Minnesota bog were found to vary considerably with peat type. Surface horizons of sphagnum moss peat contain 0.020 g. per cc. of dry material and 95 to nearly 100% water by volume at saturation. Its total porosity consisted primarily of large pores which released 0.80 cc. of water per cc. between saturation and 0.1 bar suction.Decomposed and herbaceous peats from horizons below 25 cm. had water‐holding properties strikingly different from those of the moss peats. These materials had bulk densities of 0.24 and 0.14 g. per cc., respectively, and they contained between 80 and 90% water by volume at saturation. Their porosity, though high, consisted primarily of many small pores which are not easily drained at low suctions. They retained 65 to 75% water by volume at 0.1‐bar suction.These data show that a specific change in water table elevation in the horizons containing loose, porous, undecomposed moss peat would involve a great deal more water than the same change in horizons of more dense decomposed and herbaceous peats. Thus, the hydrologic role of any bog or bog area in a watershed will depend on the type of peat found in the organic soil profile.