<p>The use of reference materials is essential to ensure the quality and reliability of measurement processes. In soil analysis, the characterization of operationally defined measurands is challenging due to the high variability of soil properties and the lack of standardized methods. The objective of this study is to develop and validate reliable measurement techniques specifically designed for the characterization of soil reference materials, focusing on the quantification of available iron, copper, phosphorus, sulfur, and chlorides. For this purpose, methods such as inductively coupled plasma mass spectrometry (ICP-MS) for metals, ion chromatography for anions, and UV–Vis spectrophotometry for phosphorus were employed. These methods were evaluated in terms of selectivity, linearity, precision under repeatability conditions, and bias. The results showed that the methods are suitable for the characterization of reference materials, achieving precisions below 3.5%, recoveries between 95 and 100%, and relative uncertainties under 4%. Additionally, the methods were applied to assess the homogeneity of two distinct reference materials, revealing homogeneity ranges between 0.48 and 5%. These methods contribute to the standardization of soil analysis, facilitating the production of reliable reference materials and supporting quality assurance in environmental and agricultural measurements.</p>