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Three factors are of significant importance regarding nitrogen contribution and mitigation of the potential for nitrate impact from the open corrals. The first factor concerns the sloping of the open corrals to manage rainwater runoff. Each corral is sloped 4% to 6% from the center to the ends to promote rainwater runoff. This water management technique reduces percolating water through the soil profile, thus preventing the creation of a hydraulic head to carry nitrate/nitrogen molecules downward. Since the open corrals are composed of clay soil material, precipitation data will not be considered as a hydraulic force as it would be with sandy soils. The second factor alleviating nitrate impact is the clay content itself. The percentage of clay in the corral area soil was found to be 42% to 47% clay by the hydrometer test. In addition, a permeability test was also conducted on representative samples taken from the open corral areas. I�I Permeability test results indicate the indigenous soils possess a hydraulic conductivity (k), of f 2 X 1V cm/sec. This rate can be considered an extremely low soil permeability. By using an average water table depth of 16 feet below grade, the following calculations illustrate it will theoretically take seventy-seven years before a nitrate laden wetting front will reach the saturated zone: 2 X 1V cm/sec X 60 sec/1 min X (525,600 min/year_30.5 cm/ft)= 0.207 ft/year. 16 ft - 0.207 ft/yr = 77 years. From this high clay content soil, the denitrification process will be expected to predominate in the subsurface anaerobic conditions. Located in the Appendix of this report, are Soil Analysis Test Results for soil taken from the open corrals in representative locations. The sample number OCO-6 represents open corral 0-6 inches in depth, while the 30-36 represents samples from the 30-36 inch depth. The significant components of this data are organic matter (O.M. ), pH, Cation Exchange Capacity (CEC), nitrate and Total Kjeldahl Nitrogen (TKN). All these parameters play an important role in nitrate formation and concentration, and also the denitrification process. The potential for nitrate development is present due to the high TKN. However the O.M. which was low at the time the samples were taken (but will increase) should create conditions favorable for denitrification. Additionally, the low nitrate present, the alkaline soil, and the high CEC are all conditions favorable for denitrification. i The third mitigating factor is the soil compaction from the animals. The hooves of the cows act essentially like a "sheepsfoot" soil compactor, creating a high density, low void space soil "cap" in the top six inches of the soil profile. Soil compaction attenuates the downward migration of nitrate molecules by reducing pore water permeability. Estimated nitrate nitrogen loading from the manure and wastewater will be discussed in Part 5 of this Section. i 6 i Vaffeu Aa Research