Conversion model of soil pH values with two extraction matrices in Urabá, Colombia ; Modelo para la conversión de valores de pH del suelo con dos matrices de extracción en Urabá, Colombia

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. ; La acidez es una de las principales propiedades del suelo y tiene relación directa e indirecta con propiedades físicas, químicas y biológicas. Su valor se determina a través de la medición del pH, metodología que varía entre los diferentes laboratorios, para lo cual las matrices de disolución más usadas son el agua destilada (H2O) y el cloruro de potasio (KCl), que dan información sobre la acidez activa y potencial, respectivamente. El objetivo del presente artículo es proponer una estrategia para relacionar los valores de pH mediante ambos métodos de extracción; para esto se realizó un muestreo de suelo a 4 puntos/hectárea en una finca bananera ...