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Soil nitrate test reports are being used more widely for making nitrogen fertilizer recommendations. Seldom does the literature refer to the ammonium concentration in the soil. Seemingly, an assumption is made that the level is insignificant or a constant. Selected soils upon which both NO 3 -N and NH 4 -Nwere analyzed were surveyed to determine the degree of variation that is found in routine soil samples from different situations. Our 134 sets of data were divided into groups by area (state) and date (month sampled). Group means and standard deviations, medians, coefficient of variations (C.V.), and ranges were determined for soil nitrate nitrogen (NO 3 -N), ammonium-nitrogen (NH4-N), sum of NO 3 -N + NH 4 -N (Sum N), % of N found as NO 3 -N, and ratio of NH 4 -N/ NO 3 -N.Values varied widely with date of sampling within areas as well as among areas. Observed values ranged as follows: NO 3 -N from 2 to 83 ppm, NH 4 -N from 4 to 30 ppm, sum of N from 9 to 91 ppm, % of N as NO 3 -N from 15 to 91% and NH 4 -N/NO 3 -N ratio from 0.1 to 5.5. C.V.'s ranged from 10 to 133%

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A final project in freshman chemistry gives students the opportunity to apply previously learned concepts to a practical problem. The final project described here uses ion-exchange resins to isolate phosphate ions from a soil matrix and the phosphate is measured as yellow vanadomolybdophosphoric acid using a spectrophotometer. The students are required to use many laboratory skills and theoretical concepts learned throughout freshman chemistry: metric conversions, pipetting, spectrophotometry, molarity, solution and standard preparation, titration, weak acid equilibria, solubility product, and ion chromatography. The laboratory experience is designed to be completed in 3-4 laboratory sessions near the end of a full year of freshman chemistry.Reports of projects such as the one described here being used in undergraduate chemical education have been limited (1, 2). The final project allows students to begin gaining the skills needed for an undergraduate research project or capstone experience. The importance of a capstone experience was emphasized in the Boyer Commission's Report (3), "All the skills of research developed in earlier work should be marshaled in a project that demands the framing of a significant question or set of questions, the research or creative exploration to find answers, and the communication skills to convey the results to audiences both expert and uninitiated in the subject matter." The laboratory experience reported here allows students to begin developing those skills early in their undergraduate education, rather than waiting until the end of their senior year.The overall model of the laboratory experience is as follows: