Multi-micronutrient foliar fertilization in eggplant under diverse fertility scenarios: Effects on productivity, nutrient biofortification and soil microbial activity

Abstract

Numerous multi-micronutrient fertilizers (MMF) have been developed during recent years to address the micronutrient deficiencies in crops and their biofortification in edible parts to overcome the malnutrition and hidden-hunger. The present field study was undertaken to know the effect of MMF on yield, nutrient biofortification in eggplant and soil microbial enzymatic activities under diverse fertility scenarios. Recommended dose of fertilizers (RDF) treatments (control, 75% and 100%) were applied in main-plots, and MMF levels (control, 0.5, 0.75 and 1.0 kg ha−1) in sub-plots under split-plot design. Growth and yield of eggplant increased significantly with increasing levels of RDF. Similar trends were observed in available soil nutrient content and microbial activities. Likewise, 1.0 kg MMF ha−1 increased growth and yield, and 0.75 kg MMF ha−1 was also found at par with the highest dose. GGE biplot analysis revealed that the application of 0.75 or 1.0 kg ha−1 MMF as foliar spray along with RDF is necessary to enhance micronutrient concentration in fruits. However, in shoot and leaves, higher levels of MMF improves nutrient content even without macronutrient application. Further, dehydrogenase activities and microbial biomass carbon was recorded significantly higher under 1.0 kg MMF ha−1. Whereas, alkaline and acid phosphatases and urease activities were higher with 0.75 kg MMF ha−1. Combined application of MMF (either 0.75 or 1.0 kg ha−1) and RDF enhances yield (18.3–21.7%) and micronutrient concentration in eggplant fruits significantly, besides improving soil biological health.