A Guide to Soil Quality Monitoring for Long Term Ecosystem Sustainability on Northern Region National Forests

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Plant Community Classification for Alpine Vegetation on the Beaverhead National Forest, Montana
PRODUCTIVITY/MANAGEMENT AND SOIL EXCERPTS

[Excerpted from: Cooper, Stephen V.; Lesica, Peter; Page-Dumroese, Deborah. Rev. 1997. Plant Community Classification for Alpine Vegetation on the Beaverhead National Forest, Montana. Gen. Tech. Rep. INT-362. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 61 p.]

TURF COMMUNITIES

Carex elynoides c.t.
(CARELY; Blackroot Sedge)

Soils—Parent materials were predominantly limestones and calcareous sandstones, but quartzites and gneiss were also represented. Mean litter and duff depths were, respectively, 0.4 and 0.3 inch. Percent of coarse fragments ranged from 8 to 75 percent with a mean of 33 percent, a figure intermediate between the grassland and cushion plant c.t.'s. Texture of the fine fraction ranged from clay to sandy clay-loam, and the modal textural class was sandy clay. Soil reactions were slightly more basic than those of grasslands with an average pH of 7.5 for calcareous materials and 6.4 for noncalcareous substrates. Mean organic matter content was 16 percent, mean total nitrogen was 0.57 percent, and C:N ratio was 15:1.

Productivity/Management—A nearly 10-fold range in productivity was recorded for both graminoids (80 to 682 lbs per acre) and forbs (115 to 977 lbs per acre). Average productivities for graminoids, forbs, and community total were, respectively, 398, 398, and 796 lbs per acre. A cline of decreasing productivity occurred from solid turf conditions to near cushion plant conditions.

Carex scirpoidea/Potentilia diversifolia c.t.
(CARSCI/POTDIV; Northern Single-Spike Sedge/Divers-Leaved Cinquefoil)

Soils—Samples were about evenly divided between calcareous (limestone and conglomerate) and noncalcareous (basalt, granite, and quartzite) substrates. Average litter and duff depths 0.6 and 0.4 inch. Coarse fragment content ranged from 0 to 31 percent and averaged 9 percent. Texture of the fine fraction ranged from fine clay to sandy clay, and modal texture was sandy clay. Soil reaction was strongly conditioned by substrate type, averaging 7.2 pH for calcareous and 5.8 pH for noncalcareous types; both values were distinctly lower than for the drier turf types. Mean organic matter content was 20 percent, mean total nitrogen was 0.73 percent, and C:N ratio was 13:1.

Productivity/Management—The range in total productivity was relatively narrow, 1,127 to 1,426 lbs per acre (average 1,283 lbs per acre), with graminoids averaging 743 and forbs 540 lbs per acre. These high values relative to the CARELY c.t. (average 796 lbs per acre) further substantiate the less stressful, higher moisture status of the CARSCI/POTDIV c.t.

Carex scirpoidea/Geum rossii c.t.
(CARSCI/GEUROS; Northern Single-Spike Sedge/Ross’Avens)

Soils—All soils were developed on intrusive igneous or metamorphosed substrates. CARSCI/GEUROS had roughly seven times more exposed soil, gravel, and rock than CARSC/POTDIV. Both litter and duff depths were shallow (0.2 inch). Coarse fragment content ranged from 6 to 39 percent and averaged 19 percent—twice that of the CARSCI/POTDIV c.t. Texture of the fine fraction ranged from sandy clay to sandy loam, while the modal textural class was sandy clay-loam. The pH values were low, averaging 5.9 and ranging from 5.5 to 6.3. Mean organic matter content was 14 percent, mean total nitrogen was 0.45 percent, and C:N ratio was 18:1. Soils were more coarse-textured, and organic matter and nitrogen contents were lower than other turf communities.

Productivity/Management—The high degree of variability in productivity appears to reflect the variability in exposed substrate. Total productivity ranged from 236 to 2,669 lbs per acre and averaged 964 lbs per acre. Productivity was 272 and 692 lbs per acre for graminoids and forbs.

Dryas octopetala/Polygonum viviparum c.t.
(DRYOCT/POLVIV; White Dryas/Viviparous Bistort)

Soils—Parent materials were limestone and quartzite. Average litter and duff depths were 0.4 and 0.5 inch. Coarse fragment content ranged from 8 to 45 percent and averaged 30 percent. Mean textural class of the fine fraction was sandy clay. Soil reaction for calcareous sites ranged from 7.4 to 7.6 pH; the lone quartzite sample was more than one pH unit lower at 6.2. Mean organic matter content was 25 percent, mean total nitrogen was 0.75 percent, and C:N ratio was 18:1. This type had the highest average organic matter and nitrogen content of any nonwetland community in our study.

Productivity/Management—Of the two plots clipped, the one from the rocky site registered only 548 lbs per acre (46 percent shrub), whereas the one with only trace amounts of exposed rock and soil produced 1,229 lbs per acre (97 percent shrub).

Salix arctica/Polygonum bistortoides c.t.
(SALARC/POLBIS; Arctic Willow/American Bistort)

Soils—Parent material included quartzite and granite-limestone mix from a contact zone. Average litter and duff depths were 0.1 and 0.4 inch. Coarse fragment content ranged from 19 to 33 percent. Texture of the fine fraction was clay. Soil reactions were slightly acid, averaging 6.50 pH. Mean organic matter content was 16 percent, mean total nitrogen was 0.43 percent, and C:N ratio was 25:1.

Productivity/Management—Total productivity ranged from 798 to 1,095 lbs per acre with shrub productivity constituting 32 to 81 percent of the total; graminoid and forb cover was 148 and 295 lbs per acre.

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