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SOIL ANALYTICAL TEST RESULTS TEST PIT SOIL NITROGEN CONTENT DOWNGRADIENT FROM FILTER BED 5 ppm m NO,-N UPGRADIENT FROM FILTER BED 6 ppm w NO3 N DOWNGRADIENT FROM PROPOSED44 ppm as NOTN TRUCK STOP - - - The nitrate-nitrogen concentrations with the soil profile illustrate the variability found in virtually every agricultural environment. The filter bed area of the downgradient soil sample location has not been farmed for many years; consequently,the nitrate-nitrogen concentration was understandably low. The upgradient soil sample was taken from the edge of cropland that has been planted in pasture grasses for the last several years, but the soil nitrate-nitrogen concentrations are only slightly higher than what would be considered a "baseline" concentration of 5 ppm NO3-N. The soil nitrate-nitrogen concentration under the parcel south of SR 132; however, is very high. In determining the cause of this concentration,we must look at the past cropping history of this soil. It is currently planted in alfalfa and has been for the past three years. It is known that alfalfa "fixes" its own nitrogen and can in fact, produce excess nitrogen which is exuded from the plant and into the soil environment. Prior crops include wheat, tomatoes, beans and peaches. Of these crops, tomatoes were probably the most heavily fertilized with nitrogen, which could also be contributing to the high residual nitrate-nitrogen concentrations. Additional chemistry on these soil samples was done to analyze several constituents that will influence nitrate loading under this parcel. The important parameters for nitrate loading assessment are the organic matter,pH, cation exchange capacity (CEC), and nitrate-nitrogen content. As noted,the organic matter in the soil profile is low for agronomic purposes, and low for providing a substrate carbon source for denitrification. Since septic effluent is composed predominately of ammonium nitrogen(NH4), the pH, along with the Cation Exchange Capacity (CEC), have significant influence on ammonium molecules. The pH of the soil profile is slightly alkaline, which would only minimally inhibit ammonium formation and stability, and therefore nitrification. The CEC measures the ability of the soil to theoretically trap and hold ammonium molecules. CEC test results of 18.9 suggests there is potential for the retention of ammonium molecules for microbial uptake, and therefore, nitrification suppression. C. PERCOLATION TEST RESULTS FOR SOIL SUITABILITY STUDY REQ'S. LLOnuly 29, 2002, one perc test boring of 42 inches in depth was prepared in the location trated on the attached site map for parcel 255-026-13. The 42 inch boring represents the imum depth of standard leachline trenches. After drilling the test borings, the bottom and 4 Chem Connkinq