|
each soil horizon. For each horizon the following field characteristics were recorded;
<br />depth and thickness of the horizon, boundary distinctiveness, Munsell color (wet),
<br />texture, structure, consistence, presence of roots and size, presence of pores, and other
<br />pertinent information. Map units identified on the field sheets represent the soil map
<br />units identified on the NRCS or USFS soil surveys and do not necessarily correspond to
<br />the map units presented in this report.
<br />Aker recording information on each soil horizon of the test pit, samples of each
<br />horizon were collected. Samples were obtained by digging into the exposed wall of the
<br />test pit within the confines of each horizon, collecting approximately 1 liter of sample
<br />and storing it in a plastic bag. Care was taken to obtain representative samples of each
<br />horizon, throughout the vertical extent of each horizon. Soil samples were labeled with
<br />the map unit, sample number, horizon, date, and sampler.
<br />After completion of field sampling, soil samples were compared by color, texture,
<br />appearance, and other visible characteristics. Soil samples were then grouped
<br />according to similar physical features as well as source location. In this way, prior
<br />mapping efforts would not prejudice the assignment of map units for this investigation.
<br />Eight distinct soil variants were identified from the samples, with one to three separate
<br />horizons within each variant. Soil samples were composited within assigned variants
<br />by soil horizon, and the composite horizon sample was separately bagged, labeled and
<br />• delivered to the Colorado State University Soil, Water, and Plant Testing Laboratory in
<br />Fort Collins, Colorado for analysis. in all, twenty-three soil horizon samples were
<br />analyzed from the SGFA. Seventeen samples were from the July 1996 sampling and
<br />six samples were from the January 1996 RPE sampling effort.
<br />soil Analysis
<br />Soil sample analysis was conducted by the Colorado State University Soil, Water, and
<br />Plant Testing Laboratory. Chain of custody was maintained for all samples from the
<br />time of sampling to delivery to the laboratory for analysis. Based on the
<br />recommendations of CDMG, each composite soil horizon sample was analyzed for pH,
<br />electrical conductivity, percent organic matter, texture (percent sand, silt, clay),
<br />estimated lime, nitrate nitrogen, phosphorus, potassium, sodium adsorption ratio
<br />(SAR), calcium, magnesium, sodium, zinc, iron, manganese, copper, selenium,
<br />molybdenum, and boron. Analysis results are presented in Tables 1 and 2 for each
<br />horizon.
<br />Analyses were made using standard extraction techniques for soil analysis. Nitrate
<br />nitrogen, phosphorus, potassium, zinc, iron, manganese, and copper were analyzed
<br />through an ammonium bicarbonate-DTPA extract. Selenium and molybdenum were
<br />analyzed through use of a hot water extract technique. Boron was evaluated using a
<br />. saturated paste technique.
<br />-4-
<br />
|