Resumo

DELGADO BEJARANO, Laura; ZAPATA HENAO, Sebastián; CASTANEDA SANCHEZ, Darío Antonio  e  BERNAL MONTERROSA, Miguel Ángel. Conversion model of soil pH values with two extraction matrices in Urabá, Colombia. Acta Agron. [online]. 2023, vol.72, n.4, pp.324-329.  Epub 25-Abr-2025. ISSN 0120-2812.  https://doi.org/10.15446/acag.v72n4.106568.

Acidity is one of the main properties of soil and is related directly and indirectly to other physical, chemical, and biological properties. It is determined through pH measurement, a methodology that varies among different laboratories. The most used dissolution matrices are distilled water (H2O) and potassium chloride (KCl), which provide information on active and potential acidity, respectively. The objective of this work was to propose a strategy for relating pH using the above extraction methods. For this purpose, soil sampling was conducted at a density of 4 points per hectare (ha) on a banana farm in the Urabá region (Antioquia) to develop regression models between the pH develop in a KCl [1M] solution and in H2O, using two dissolution ratios (soil:solution) of 1:1 and 1:2. The most representative model for the studied area was obtained using the 1:2 ratio, under a third-degree polynomial regression described by the equation pHKCl = -0.12 +2.31 -13.41 + 28.10, which yielded a coefficient of determination (R2) of 83.91 % and a root mean square error (RMSE) of 0.27. Additionally, no significant differences were found between the two dilution ratios evaluated. Thus, it can be concluded that for the Urabá region, mathematical models can be used to convert pH values between H2O and KCl, enabling the estimation of potential acidity values for neutralization purposes.

Palavras-chave : acidity in soil; agriculture; amendments; fertilization; model of pH.

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