Effective nutrient management is essential to meet the nutritional needs of a growing global population while minimizing the environmental footprint of pasture systems. A comprehensive evaluation of plant nutrition involves soil fertility testing combined with foliar diagnosis, which assesses both soil nutrient availability and plant uptake. The chapter stresses the importance of establishing updated reference values for pasture nutritional diagnosis. Enhancing the accuracy of diagnostic tools like DRIS and CND is critical for efficient nutrient management. Future research should focus on refining these nutritional interpretation methods, particularly for pastures, to ensure that agricultural practices are based on precise, scientifically validated diagnoses. This will ultimately lead to improved productivity and the sustainable use of natural resources.