The relation of laboratory analyses for copper, zinc, and molybdenum in some Victorian soils to the results of field trials

Abstract

Samples of surface soil from 82 fertilizer trial plots in Victoria were analysed for total copper, zinc, and molybdenum, and for the amounts of these elements extracted by EDTA and normal ammonium acetate, and these values were related to plant responses to fertilizers containing these elements. Predictions of copper deficiency can be made with equal accuracy from a knowledge of the total concentration or from the EDTA soluble copper. For zinc, an approximately equal accuracy of prediction can be made either from the total zinc content and soil reaction or from the EDTA soluble zinc and soil reaction. There was no relation between total or extractable molybdenum and deficiency. The amounts of copper and zinc, but not molybdenum, extracted by both extractants were correlated with the total concentrations in the soil. (r = 0.80 for EDTA Cu, 0.76 for ammonium acetate Cu, 0.47 for EDTA Zn, and 0.32 for ammonium acetate Zn.) The total concentrations of copper and zinc were also correlated with the nitrogen content of the soil (r = 0.38 for Cu, 0.42 for Zn), as were the amounts of copper (r = 0.46), zinc (r = 0.42), and molybdenum (r = 0.43) extracted by EDTA, and the amounts of copper (r = 0.36) and molybdenum (r = 0.40) extracted by ammonium acetate.