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I. INTRODUCTION <br /> This report contains the results of the Nitrate Loading Study conducted by Valley Ag Research <br /> for the existing Tosta Dairy Facility. The subject dairy is located northwest of the City of Tracy, <br /> at 20662 San Jose Road. This dairy site is referenced as the "home" dairy. The Tosta's are <br /> currently operating another dairy facility on Reeves Road, one-half mile to the west of the home <br /> dairy. This facility is referenced as dairy #1. The Tosta's will suspend operation of this dairy and <br /> move all animals to the home dairy, upon its completion. Completion includes construction of <br /> additional freestall barns, corrals and enlargement of waste containment structures. There are <br /> additional animals owned by the Tosta's located on pasture near the Escalon area. These animals <br /> may eventually be moved onto the home dairy. Consequently, this report addresses only the <br /> home dairy. Total acreage owned by the Tosta's is 423 Ac: The actual dairy site = 10 Ac and the <br /> cropland= 413 Ac. Waste application areas are outlined in the Appendix. <br /> The purpose of this investigation was to quantify and assess the potential nitrate-nitrogen impact <br /> to the soil and groundwater underlying the nutrient application acreage. With the proposed <br /> increase in animal units at the home dairy site, this report establishes the quantity of nitrogen <br /> produced correlates with the nutrient capacity of the referenced cropland. This study is in <br /> compliance with the requirements of Section 9-1110 item (c) of the San Joaquin Ordinance <br /> Codes. <br /> The San Joaquin County Environmental Health Department considers nitrate contamination a <br /> serious threat to the surface and groundwaters of the County. High nitrate concentrations in <br /> drinking water can have deleterious effect on infants and fetuses and may also induce abortion in <br /> cattle. The United States Environmental Protection Agency (EPA) has determined 10 mg per <br /> liter of nitrate-nitrogen (NO3-N), equivalent to 45 mg per liter nitrate (NO3) in drinking water to <br /> be the Maximum Contaminant Level (MCL). By conducting these types of investigations, the <br /> County is better able to locate, quantify and monitor the potential for nitrate impact and impose <br /> prevention and/or mitigation measures. <br /> Our research of the subject facility included historical agricultural considerations, soil testing and <br /> analyses, groundwater analyses, and manure and wastewater analytical data found in the scientific <br /> literature. By examining the chemical and physical properties of the soil and water, the potential <br /> of nitrate accumulation can be adequately assessed. <br /> The surrounding study area consists mainly of irrigated agriculture and pasture. There are five <br /> dairies of various size in the one-mile radius from the Tosta home dairy. Past history of the <br /> subject property is irrigated row crop, forage and pasture. <br /> This document also serves as a directive towards best management practices of nutrient/waste <br /> materials. Our investigation demonstrates that animal wastes produced at the subject dairy, can <br /> be applied to cropland owned by the Tosta's, providing nitrogen in a timely manner to meet crop <br /> N requirements. <br /> 1 <br /> va!!ey Ag P pearck <br />