Studies on effect of Phosphate solubilizing bacteria PSB for the optimization of Cauliflower Productivity

Abstract

Cauliflower Brassica oleracea var. botrytis is an agriculturally important vegetable that contributes significantly to global nutrition and farmer livelihoods. However, the growing demand for high-yield cultivars has led to an overreliance on chemical fertilizers and pesticides, resulting in environmental degradation, such as soil depletion, water pollution, and adverse health effects. To address these issues, there is increasing interest in adopting sustainable agricultural methods. Among these, the use of biofertilizers, particularly phosphate-solubilizing bacteria PSB and nitrogen-fixing microorganisms NFM has emerged as a promising strategy to boost soil fertility, improve nutrient absorption, and enhance crop productivity while mitigating ecological harm. Phosphorus, a vital macronutrient for plants, plays a critical role in energy transfer, signal transduction, and photosynthesis. Despite its importance, much of the phosphorus in soils remains insoluble and unavailable to plants. Conventional P fertilizers often have low uptake efficiency 15 20 due to rapid fixation in the soil. Similarly, nitrogen, another essential nutrient, requires microbial transformation into bioavailable forms. Integrating PSB and NFM into agricultural practices can improve nutrient availability and support sustainable cauliflower cultivation. This study aimed to isolate, identify, and characterize native PSB from the rhizosphere of cauliflower fields in three key agricultural districts of Uttar Pradesh Lucknow, Unnao, and Kanpur. The objectives included evaluating the synergistic effects of PSB and NFM, optimizing microbial formulations for field application, and analyzing their economic feasibility. Soil samples from a 0 20 cm depth were collected to target the rhizosphere, the zone of intense plant microbe interaction. PSB isolates were obtained via serial dilution and cultured on Pikovskayas medium, where clear halo zones indicated phosphate solubilization. Isolates were subjected to morphological and biochemical tests, followed