Abstract

PELLEGRINI, Andrea E; SUCUNZA, Florencia A; MILLAN, Guillermo  and  VAZQUEZ, Mabel E. Comparación de metodologías analíticas para diagnosticar suelos con enmiendas básicas en el ámbito templado argentino. Cienc. suelo [online]. 2016, vol.34, n.1, pp.1-12. ISSN 1850-2067.

It is unknown whether pH and cation exchange capacity protocols currently used are also suitable for monitoring limed soil acidity evolution. The objectives of this study were to analyze the diagnostic performance over time of current and potential pH tested in two acid soils of the Buenos Aires province, treated with different doses of basic amendments, using two dilutions and two cation exchange capacity and exchangeable bases protocols. The experimental units were 750 g pots maintained at 80-90% of soil field capacity; the incubation time was of 3, 6, 9, and 12 months. The corrector applications were equivalent to 0,750, 1.500 and 2.000 kg ha^-1 of CaCO₃ and CaCO₃-MgCO₃ respectively. Current and potencial pH were determined potentiometrically in a 1:2,5 water and 1:1 KCl relation respectively. Also cationic exchange capacity (CEC) with 1M NH4 acetate pH 7 as extractant and cationic exchange capacity not buffered (CICnb) with 0.2 M NH₄Cl extractant at soil´s pH were determined. The four protocols used to evaluate the pH were highly associated. The four pH measures were able to discriminate liming rates although the current pH 1:2,5 presented the greatest differences. However, actual pH measurements were more volatile than the potential pH, at any dilution. The results indicate that 6-month anticipation liming may be sufficient for sensitive crops in soils with similar pH to those studied here. None of the determination methods for the cation exchange capacity and the saturation of the bases resulted in a size increase before liming or to discriminate the effect of each rate.

Keywords : Limestone; Dolomite; Determination protocols; Residuality.

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