Synergistic Effect of Humic Acid and Phosphate-Solubilising Bacteria (PSB) on Leaf Yield and Chlorophyll Content of Green Leaf Vegetables

Amity Institute of Organic Agriculture, Amity University, Noida (U.P )

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Abstract

Green leafy vegetables require adequate nutrient availability, particularly phosphorus, for optimum leaf yield and chlorophyll synthesis. However, excessive use of chemical fertilizers has led to declining soil health and environmental concerns, necessitating sustainable nutrient management strategies. This review examines the synergistic effects of humic acid (HA) and phosphate-solubilising bacteria (PSB) on the growth and productivity of green leafy vegetables. Relevant literature was analyzed to evaluate their influence on nutrient availability, plant growth, chlorophyll content, and yield. Findings indicate that humic acid enhances soil properties, root growth, nutrient uptake, and chlorophyll biosynthesis, while PSB improve phosphorus availability through organic acid production and rhizosphere activity. Individually, both inputs promote leaf number, leaf area, biomass accumulation, and chlorophyll content. More importantly, their combined application produces a synergistic effect, as humic acid supports microbial survival and activity, thereby enhancing PSB-mediated phosphorus solubilization and nutrient uptake. This interaction results in improved photosynthetic efficiency, higher chlorophyll concentration, increased leaf yield, and reduced dependence on chemical fertilizers. Overall, the integrated use of humic acid and PSB represents an eco-friendly and sustainable approach for enhancing productivity, soil health, and resource-use efficiency in green leafy vegetable cultivation.