Comparative Evaluation of Nutrient Balance in Sugarcane Using DRIS and CND Models: A Two-Year Study Field in Shuaibiyeh, Southwest Iran

Nutrient imbalance is a significant constraint in achieving optimal crop productivity. The availability of nutrients throughout the crop cycle is crucial for normal plant development, making nutrient management a key factor in maximizing yield. This study evaluated the nutrient balance status of sugarcane (Saccharum officinarum L.) using the Diagnostic and Recommendation Integrated System (DRIS) and Compositional Nutrient Diagnosis (CND) models over a two-year field experiment (2023–2024). Leaf samples were collected at various phenological stages from commercial sugarcane fields in Shuaibiyeh, Khuzestan Province (southwest Iran), and analyzed for macro- and micronutrient contents. DRIS and CND indices were computed to identify nutrient imbalances and determine priority elements for correction. Results indicated that the CND model demonstrated a stronger correlation with yield (R² > 0.9) compared to DRIS. According to the CND indices in low-yielding fields, the priority order of nutrient deficiencies was: Zn > Mn > Mg > Fe > Ca > K > N > Cu > P. In contrast, the DRIS method classified nutrient priorities into high and low consumption categories, identifying the order as: Zn > K > Mg > Mn > Ca > N > Fe > Cu > P. Both diagnostic methods consistently identified zinc as the most limiting nutrient, while phosphorus frequently appeared in excess. These findings highlight the superior diagnostic capability of the CND model and underscore the need for balanced nutrient management strategies to enhance yield and promote sustainability in sugarcane agroecosystems.