Ornamentals, fruit and vegetable crops are commonly tested for inorganic anions, NO3-N, PO4-P, Cl and SO4-S, to identify the nutritional status of the plant. Two percent (0.20 M) acetic acid has primarily been used as the extractant for these inorganic anions. The use of acetic acid does not quantitatively extract SO4-S and PO4-P. Research using calcium formate was initiated to assess its effectiveness as an universal extractant for inorganic anions. Results of a series of experiments will be presented identifying the optimum calcium formate concentration, extraction time, and extractant sample ratio for quantitative removal and measurement of NO3-N, PO4-P, Cl and SO4-S. Results of spiking experiments will be presented using a range of horticultural crops important to California agriculture. Additional data will be presented on the use of calcium formate for the determination of K and NH4-N in botanical tissues.
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