Soldiers Delight plant and soil data 2000

Materials and Methods
Site Description
Soldiers Delight Natural Environment Area (NEA) is comprised of 1,900 acres of serpentine barren located within the Maryland Piedmont physiographic region. The area is known to contain 39 rare, threatened, or endangered plant species as well as rare insects, rocks and minerals. Soldier’s Delight is characterized by forested communities dominated by Quercus marylandica; large expanses of open prairie-like grasslands sparsely populated with oaks Quercus marilandica, Quercus stellata; and “barren” areas, containing shallow serpentine soils and small, xerophytic plants of species adapted to stressful conditions. In addition, Pinus virginiana has been invading large expanses of Soldier’s Delight and is a significant threat to the serpentine nature of this protected area (Tyndall, 2005).

Seven serpentine and three non-serpentine areas were selected for study at Soldier’s Delight. Serpentine study areas were located on serpentine soils classified as chrome channery silty loam. The three control areas were adjacent to the serpentine areas of Soldier’s Delight and contained non-micaceous, nonserpentine schist soils.
Within each serpentine area, three plots were established to represent distinct successional plant communities (Bare Rock, Open Grass, and Wooded) associated with early, mid, and late succession at Soldiers Delight. Bare Rock plots were characterized by outcrops of exposed serpentinic rock, low vegetative cover, and shallow soils. Vegetation was dominated by weedy species, grasses, and low growing Phlox spp. Open Grass plots had dense vegetative cover dominated by tall prairie grass species. The soils had a thin organic surface layer and a shallow, more fully developed subsurface soil strata. Wooded plots were more diverse, ranging from fully developed pine and/or hardwood forest ecosystems with low understory growth and a thick canopy to a prairie-to-pine transitional structure with pines and shade tolerant understory such as Vaccinium corrymbosum and Smilax rotundifolia. Soils in the Wooded plots were relatively shallow but more fully developed than the Open Grass plots. Wooded plots often inhabited steeper grades where water was present.

Twenty four plots of varying dimensions were established for sampling (3 communities X 7 serpentine areas, 3 non-serpentine plots). Plot dimensions were based on the minimal area concept, in which the plot is the smallest area that contains an adequate representation of the community species. Open Grass plots were uniform and sampled in 1m x 1m quadrats. Bare Rock and Wooded plots were 7m x 4m. These rectangular plots ran parallel to the geographical gradients to encompass more heterogeneity. Three control plots, 7m x 4m, were non-serpentine pine forests with little or no understory or heavy leaf litter. The soils at the non-serpentine plots were classified as Chrome silt-loam, Manor loam, and Manor channery loam.

Sampling and Analysis Preparation: Plants
Plants were sampled from late spring through early fall for each of three collection seasons. Leaf and needle samples were collected by hand on a single leaf basis and composited in paper collection bags. Varying number of plants were sampled in order to obtain at least 2 g dry weight of leaf tissue for analysis. The youngest, fully developed leaves were collected from random individuals of each species in a sample plot. Plant tissue samples were analyzed for phosphorous, nickel, manganese, iron, magnesium, and calcium.

Sampling and Analysis Preparation: Soils
Soil samples were obtained from each plot using shovels due to the rocky nature of the serpentine area. Open Grass and Wooded soils were sampled at the organic layer, 0-5 cm, and 5-15 cm depths. The thin soil layer at the surface of Bare Rock plots was sampled as the “bare rock” depth. Soils were sampled from five random locations in each plot, composited, air dried, crushed to < 2 mm sieve particle size and mixed for analysis.

Soil pH was determined from a 2:1 deionized water to soil slurry. Total metals were extracted using the aqua regia procedure. Dilutions of the concentrated extract were prepared using 1N HCl for flame atomic absorption spectrophotometry (AAS). Available soil nutrient levels were determined using DTPA and Sr(NO3)2 extractions. Available phosphorous levels were examined with the Bray-1 P test. Elements analyzed for aqua regia were Ca, Mg, Mn, Fe, Ni. Elements analyzed after DTPA extraction include Fe, Ni, Mn, and Zn. Sr(NO3)2 extracts were analyzed for Ca, Mg and Ni on the ICP-AES while AAS was used to detect levels of K, Ni, and Zn.