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Nitrate-nitrogen is determined by shaking a 2-gram scoop of soil with 30 milliliters of calcium sulfate extracting solution for 15 minutes. Nitrate in the filtered extract is measured on a Lachat QuickChem 8500 Flow Injection Analyzer by the cadmium reduction method. The results are reported as parts per million nitrate-nitrogen (NO3-N) in the soil.  If samples covering the range from the surface to 2 feet in depth are submitted, results are reported as pounds per acre of nitrate-nitrogen (NO3-N) in the top 2 feet of soil.