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. IV. SOIL PHYSICAL AND CHEMICAL ANALYSIS RESULTS <br />Tables 1 and 2 present the results of analyses on the four soil types identified in the <br />forty soil test pits in the SGFA. Table 1 presents the analysis results from samples <br />taken in July 1996. Table 2 provides analysis results from samples originally taken in <br />Sylvester Gulch for the RPE project in January 1996. Each table identifies the soil unit <br />and horizons. Based on the initial compositing of samples and subsequent map unit <br />correlation, it is evident that differences exist within the map units. Table 1 illustrates <br />the results of the differences within the Beenom-Absarokee association (two distinct <br />variants), the Fluvent group is represented by two variants, and the Torriorthents have <br />three variants. The Work loam was consistent throughout the study area. Within each <br />table, the soil type and variant, and horizons are identified, with corresponding values <br />for physical and chemical parameters listed. The characteristics of each soil type by <br />parameter will be briefly reviewed. <br />pH <br />Hydrogen ion concentration (pH) is an indicator of the acidity or alkalinity of a soil. <br />Extremes in pH (5.5 <pH> 8.5) can indicate conditions in soils detrimental to plant <br />. growth, most often due to high concentrations of cations which have increased mobility <br />at low or high pH values. Within the soil types identified in the SGFA, none of the <br />horizons had either significantly low or high pH readings. The range in pH readings <br />was from a low of 6.4 in the B horizon of a Torriorthent (Table 2) to a high of 8.2 in <br />the Fluvent(2) C horizon. All pH readings were close to the neutral pH (7.0) <br />indicating neither significant release of cations or anions in the soil environment. In <br />the Work loam, Beenom-Absarokee association and one Fluvent(2), soil pH rose <br />slightly with depth, from slightly acidic conditions to nearly neutral or basic. With one <br />exception, Torriorthents reflected slightly acidic conditions within the shallow soils, <br />possibly related to the tannic acid released by Gamble's oak leaves upon <br />decomposition. The Torriorthent exception was located in a sedge meadow on a steep <br />slope at the northern edge of the study area. The pH at this location was slightly basic <br />(7.8). <br />ELECTRICAL CONDUCTIVITY (EC) <br />Electrical conductivity (EC) is a measure of the amount of soluble salts in the soil. <br />With an increase in soluble salts in the rooting zone of the soil, plant seedling <br />establishment and growth may be inhibited. Samples from the soil horizons in the <br />SGFA were consistently very low and ranged from 0.1 mmhos/cm in the Work loam <br />samples (B, B/C horizons) to 0.8 mmhos/cm in the Fluvent(2) C horizon. The <br />majority of the readings were in the 0.3-0.4 range. There was no significant evident <br />correlation between depth and EC value in the SGFA samples. <br />-9- <br />