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f - IT ' SOIL PARTICLE SIZE ANALYSIS AND NITROGEN CONTENT LOCATION DEPTH SAND% SILT% CLAY% USDA SOIL NITRATE-N F TEXTURE CONTENT 42 Inches 55 30 14 SANDY LOAM 11 ppm NO,-N WEST PARCEL 12 feet 27 48 24 LOAM I I ppm NO,-N 24 feet 29 38 32 CLAY LOAM 10 ppm NO;N MIDDLE 42 Inches 31 40 28 CLAY LOAM 10 ppm NO;N ( PARCEL f 42 Inches 17 40 42 SILTY CLAY 14 ppm NO,-N I EAST PARCEL 14 feet 61 28 10 SANDY LOAM 11 ppm NOi N E k 24 feet 55 26 18 SANDY LOAM 10 ppm NO,-N During the drilling procedures for the deep perc test borings,no saturated soil conditions were encountered down to 24.5 feet. Soil moisture content was observably higher for the West Parcel boring in comparison to the other two borings. This may be attributable to vadose zone water draining faster through the higher porosity subsoils in the middle and east areas in comparison with the finer- grained soils on the west end of the property. It is a possibility that perched water table conditions exist ' above the static water table depth, although unlikely for any substantial amount of time. No rust mottling was observed in the upper soil profile, and only very slight mottling at the deeper depths of the middle and e r p cast parcels where the Sandler material was encountered. Although rust mottling may be attributed to geologic processes, it may also be due to seasonal soil saturation whereby percolating soil water encounters larger porosity soil and accumulates on top of these strata. It occurs when anaerobic bacteria decompose organic matter and use iron (Fe") in the metabolic processes. This oxidation of iron creates rust. When organic matter and an anaerobic environment are present within the soil environment; denitrification may be enhanced. I Important soil parameters for nitrate loading assessment are the organic matter content, pH, cation exchange capacity(CEC), clay content percentage, soluble salts, and the nitrate-nitrogen content. Considering the property soils have not been under agricultural production for many years, the organic matter content in these soils is low, contributing to a low estimated nitrogen release(ENR). �r The significance of cation exchange becomes important when the chemistry of septic effluent is analyzed. Nitrogen in septic tank effluent consists of approximately 75%N as the ammonium (NH4}) ion form and 25% N in the organic form. If the ammonium ion is bound and eventually used, nitrification cannot occur. Consequently, the pH, along with the CEC, have significant influence on ammonium molecules. The CEC measures the ability of the soil to theoretically trap and hold ammonium molecules. All of the soil samples indicate a comparatively high CEC. This suggests there is a greater potential for the retention of ammonium molecules for microbial uptake and suppression of nitrification. Cations such as NH,', K�', Cay* and Mg++ are removed from solution by the clay soil fraction because the clay particles possess a negative charge. 4 i C&sney Consulting