In an attempt to enhance the precision of chemical analyses of soil fertility and quantify different elements simultaneously, some laboratories have opted to use the technique of inductively coupled plasma for optical emission spectrometry (ICP) instead of the technique of Atomic Absorption Spectrometry (AAS), which currently is the most commonly used in soil analysis laboratories. In this study we compared the precision of the two dosage techniques, their repeatability and the magnitude of the concentrations of the micronutrients Fe, Zn, […]

The determination of the potential acidity (H + Al) of soil samples by the calcium acetate 0.5 mol L-1 pH 7.0 method (conventional method) is most used in Brazilian laboratories. Other methods, which are more practical for routine analyses, have been tested with success for various soil groups, but not for those located in the northeast of the State of Pará. With this objective, twenty-seven representative soil samples were analyzed by the conventional Ca(OAc)2 method. The pH of equilibrium in […]

The potential extractable acidity method by Ca(OAc)2 0.5 mol L-1 is widely used in Brazilian soil analysis laboratories. To define the calibration curve between potential extractable acidity and buffered pH SMP, 102 samples of soils from Rio de Janeiro State, Brazil, were analyzed in 1996. The data showed that potential acidity can be estimated by pH SMP buffer suspension (R2 = 0.90**) and that the pH of Ca(OAc)2 0.5 mol L-1 suspension was significantly correlated with the pH SMP.