Assessment of Sugarcane Nutritional Imbalances in Burundi’s Sosumo Industrial Plantations Using the CND Diagnostic Approach

The present study evaluated the nutritional status of industrial sugarcane (Saccharum officinarum L.) plantations managed by SOSUMO in Burundi using the Compositional Nutrient Diagnosis (CND) method via the CNDr² index. Foliar samples from 41 plots were analysed for seven key nutrients: Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Copper (Cu) and Zinc (Zn). A CNDr² threshold of 7.4 was established to identify significant nutritional imbalances. Results showed that 56.1% of plots had low yields linked to nutrient deficiencies, mainly Magnesium (27%), Nitrogen (17%), and Potassium (15%). Zinc and Copper deficiencies affected 12–14% of plots. About 22% of plots had low yields despite balanced nutrition, highlighting non-nutritional factors such as soil or management issues. Conversely, 9.8% of plots achieved high yields despite imbalances, suggesting short-term compensation through intensive practices. The CNDr² index proved a reliable tool for diagnosing nutrient imbalances and guiding fertilisation strategies aligned with the 4R nutrient stewardship principles. The study underscores the importance of adapting nutrient recommendations to local soil, climate, and crop conditions while addressing non-nutritional constraints to sustain and improve sugarcane productivity in Burundi.