Integrated nutrient management, soil biological functions, and their linkages with fruit quality in mango (Mangifera indica L.) under medium-density planting

Integrated nutrient management (INM) combining reduced recommended fertilizer doses (RDF) with foliar micronutrients may improve soil health and fruit quality in tropical mango orchards. This study evaluated INM strategies for soil properties, plant nutrient status, and fruit quality in medium-density Dashehari mango. A field experiment was conducted during 2023–2024 using a randomized block design with three replications. Ten INM treatments comprising 100%, 75%, 50%, and 25% RDF, with or without soil-applied micronutrients and one or two foliar micronutrient sprays, were evaluated. Soil chemical properties, microbial populations, enzyme activities, leaf and fruit nutrients, and fruit quality were assessed. Principal component analysis (PCA), redundancy analysis (RDA), correlation, and regression analyses examined relationships among variables. Treatments T 8 (75% RDF + two foliar micronutrient sprays) and T 9 (50% RDF + two foliar micronutrient sprays) consistently improved soil biological properties, available soil nutrient & total leaf nutrient status, and fruit quality compared with 100% RDF. Both treatments increased arbuscular mycorrhizal fungi (AMF) spore density, bacterial populations, and enzyme activities. These improvements were associated with higher total soluble solids (20.78 °Brix), sugars, ascorbic acid, carotenoids, flavonoids, total phenols, antioxidant activity, and shelf life. Soil organic carbon and micronutrient responses varied, with some highest values under T 5 . Soil pH changes were statistically significant but relatively small. Multivariate and correlation analyses showed positive associations among soil biological properties, nutrient availability, plant nutrient status, and fruit quality. Applying 50–75% RDF with two foliar micronutrient sprays improved soil biological functioning, nutrient availability, plant nutrient status, and fruit quality under the conditions of this study. Reduced fertilizer rates supplemented with foliar micronutrients may support efficient and sustainable nutrient management in medium-density tropical mango production systems and orchard sustainability.