Peat Bulk Density Research Articles

Vegetation-Environment Relations in a Conifer Swamp in Central New York

PARATLEY, R. D. AND T. J. FAHEY (Dept. Natural Resources, Cornell University, Ithaca, NY, 14853). Vegetation-environment relations in a conifer swamp in central New York. Bull. Torrey Bot. Club 113:357-371. 1986.-Direct and indirect gradient analysis techniques were employed to quantify the relationships between vegetation and environment in a valley-basin swamp forest in central New York State. It was hypothesized that soil drainage, as indicated by water table position, would be the most important environmental factor ordering vegetation in the swamp, with a secondary influence by site quality as influenced by spatial position with respect to surface and groundwater inflow. The direct gradient analysis, based upon weekly measurements of water table height, sorted the site into five drainage classes and clearly demonstrated the primary control on woody vegetation distribution. However, the indirect gradient analysis, based upon overstory and ground vegetation composition, was more successful in sorting the vegetation into meaningful communities. The overstory vegetation was divided into an upland community occurring on inceptisol, and three swamp communities on histosol (hemlock swamp, and white pine and larch phases of a mixed conifer-red maple swamp). The ground vegetation subdivided the mixed coniferred maple swamp into four communities named for indicator species. Environmental correlation suggested that these divisions were largely the result of site quality differences as influenced by proximity to mineral-rich inflow. The ground vegetation communities were more clearly separated in the ordination space than the overstory, and were more highly correlated with mean depth of water table, ash content and bulk density of peat. Thus, the gradient analyses supported the hypothesis of environmental control of vegetation distribution. Finally, the high species richness (272 vascular plants) resulted from high microsite heterogeneity, the complex hydrology of the basin, and the mixing of boreal relict vegetation with temperate swamp species typical of the region.

HYDRAULIC CONDUCTIVITY AND RELATED PHYSICAL PROPERTIES OF PEAT, LOST RIVER PEATLAND, NORTHERN MINNESOTA

We measured hydraulic conductivity (K), bulk density, and humification of peat in three soil profiles at a spring fen-raised bog complex in the Lost River Peatland, northern Minnesota. Piezometers were installed at saturated depths ranging from 0.5 to 3.0 m on a raised bog, its external fen margin, and an adjacent spring fen, and field K was determined by time-lag methods. Field K ranges from 2.5 x 10−4 to 5.6 x 10−3 cm/s on the bog, from 1.5 x 10−3 to 2.6 x 10−2 cm/s at the fen margin, and from 6.7 x 10−4 to 1.6 x 10−2 cm/s on the spring fen. The K determined for partially decomposed peat deeper than 1 m is 2 to 6 times greater than previously reported in the literature. There appears to be little correlation of K with depth, as suggested by most other workers who have investigated only the uppermost “active‘’ layer, about 50 cm deep. Laboratory analyses of K from peat cores show that the ratio of horizontal K (Kh) to vertical K (Kv) is highly variable throughout the peat column. Kh is generally one to two orders of magnitude greater than Kv. Bulk density values are similar to those found for other moderately decomposed peats in Minnesota, ranging from 0.06 to 0.14 g/cm3. Bulk density and humicity do not statistically correlate with depth or with K for the peats in the Lost River Peatland. This study suggests that humified peat can transmit groundwater more rapidly than previously thought and that the interaction between groundwater in the peat and associated surface waters can be significant.

Soil characteristics of raised sphagnum bog in relation to intensively grown deciduous species

Peat bulk density, water content, and pH were studied on a raised bog in central Sweden with particular attention to the demand of the crops. Volume defined samples of the 0–30 cm soil layers were taken during 1981 and 1982 in order to find out seasonal patterns and between‐treatment variations of the soil characteristics. Four plots with different liming, fertilization, and irrigation regimes were included in the investigation. Two willow plots (Salix viminalis and S. dasyclados) and one plot with Alnus incana were all irrigated‐fertilized by drip tubes during the growing season while an unplanted reference plot was not. Large variations in the studied soil properties occurred within all the plots at any time, to a great extent depending on variations in the mixture of Eriophorum and Sphagnum in the peat. Peat bulk density tended to be higher in the irrigated‐fertilized plots than in the reference plot and averaged about 70 and 63 g . dm−3, respectively. Water content increased rapidly with depth in the ...

The bulk density of peat and its determination.

The bulk density of peat and its determination.