Soybean Seed Analysis as a Nutritional Diagnostic Tool

Our study examined whether the nutrient content analysis of soybean seed could be used to assess the plant nutritional status, generating results as or more accurate than those obtained by leaf analysis. We hypothesized that soybean nutritional assessment could be carried out using seeds as a reference. Nutritional diagnosis in soybean leaves and seeds was assessed using the Mathematical Chance (MCh), Diagnosis and Recommendation Integrated System (DRIS), and Compositional Nutrient Diagnosis (CND) methods. Results showed that optimal nutrient levels in soybean leaves and seeds estimated by DRIS and CND were equal or close to the average content in the reference population, while slightly different values were obtained by MCh method. Nutrient average contents were larger for soybean seeds than for leaves for nitrogen, phosphorus, sulfur, and zinc; and lower for potassium, calcium, magnesium, boron, copper, iron, and manganese. The ranges of optimum levels obtained for seed nutrient content showed normality in results for the three studied methods (MCh, DRIS, and CND). This indicates that using seeds as a diagnostic tissue for assessing soybean nutritional status is promising. Optimal nutrients levels in soybean seeds estimated mainly by the CND and DRIS methods could help to monitor soybean nutritional status.