Nutrient uptake by snapdragon (Antirrhinum majus L. 'Peoria') was compared at five root-zone temperatures: 8, 15,22,29, and 36°C. Uptake of nitrate (NO 3 --N), ammonium (NH 4 + -N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), boron (B), iron (Fe), manganese (Mn), and zinc (Zn) responded quadratically to increasing root-zone temperature. Greatest nutrient uptake temperature varied with nutrient but ranged from 15 to 29°C. Uptake of copper (Cu) and molybdenum (Mo) were unaffected by root-zone temperature. Dry weight gain and stem length also responded quadratically to increasing root-zone temperature. Optimal temperatures for nutrient uptake and growth were similar, averaging 22°C. These results indicate increasing or maintaining root-zone temperatures near 22°C maximizes growth and nutrient uptake of snapdragons.

Nutrient uptake by `Apache', `Jersey City', `Peoria', and `Philadelphia' snapdragons (Antirrhinum majus L.) was compared at three developmental stages: Stage I, vegetative to bud initiation; Stage II, bud initiation to visible bud; and Stage III, visible bud to anthesis. Significant differences in uptake occurred between one or more developmental stages for all nutrients tested: \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{NO}_{3}^{-}\mathrm{-}\mathrm{N},\mathrm{NH}_{4}^{+}\mathrm{-}\mathrm{NB}\) \end{document}, B, Ca, Cu, Fe, K, Mg, Mn, Mo, P, and Zn. Uptake of most of the nutrients increased or remained high during Stage III. These results indicate that the current cultural practice of stopping fertilization at bud elongation should be reexamined. Differences in uptake between cultivars were found only for \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{NO}_{3}^{-}\mathrm{-}\mathrm{N}\) \end{document}, as uptake by `Apache' was significantly higher than uptake by `Philadelphia'.

In 1994, the Soil and Plant Analysis Council initiated a ProficiencyTesting program for soil testing laboratories in the United States and Canada. The program consists of a semi-annual (January and July) exchange of five soil samples.Participating laboratories can test the samples for up to ten different analytes following analytical methods recommended by geographic region. The data is collected and subjected to statistical analysis and data summaries are provided to the participants. Data summaries are reported here from results of the January, 1995 exchange. Of the analytes tested, the least variability was found for water and buffer pH while greatest variability was found for chloride and soluble salts. Variability of test results for phosphorus was greater than that of the other macronutrients regardless of soil test procedure employed. On the average, 53 to 80% of the participating laboratories had results that were within +/-1 standard deviation of the mean for the analytes tested while 76 to 100 % had results that were within +/-2 standard deviations of the mean. Future improvements of the Council's Proficiency