SYNERGISTIC EFFECT OF Bacillus spp. AND Aspergillus spp. AS BIOFERTILIZERS SPRAY ON NUTRIENT UPTAKE AND GROWTH ENHANCEMENT IN LETTUCE (Lactuca sativa) AND RADISH (Raphanus sativus): IMPACT OF BIOFERTILIZER ON SOIL FERTILITY AND SUSTAINABLE AGRICULTURE

Abstract

Excessive use of chemical fertilizers has led to soil deterioration, water pollution, and the loss of biodiversity, hence requiring eco-friendly alternatives. The concept of biofertilizer emerges as an alternative approach for improving soil fertility and agricultural productivity. The objective of this study was to isolate Phosphate Solubilizing Bacteria (PSB), Phosphate Solubilizing Fungi (PSF), and Nitrogen-Fixing Bacteria (NFB), following the development of biofertilizers sprays that offer a promising solution by improving nutrient availability and promoting plant growth through microbial interactions while minimizing chemical fertilizers dependence. Soil associated with open dump sites and compost sites in the Karadiyana was selected to isolate the PSB, PSF, and NFB strains. Genotypic identification, analysis of antagonistic effect, and nutrient solubilization efficiency were performed for each isolate. A microbial consortium was prepared to consist of four Bacillus spp. and two Aspergillus spp. and incorporated into a fertilizers spray, which was applied to the leaves of Lettuce (Lactuca sativa) and Radish (Raphanus sativus) grown in compost, coir dust, and soil medium. Plants were measured for various growth parameters after 30 days of seed germination. Growth parameters, including shoot length, root length, wet weight, dry weight, seed germination time, leaf area, leaf length, leaf width, and the number of leaves of Lettuce plants, were significantly influenced by the application of fertilizer spray compared to control pots (p < 0.05). Lettuce and radishes showed shoot lengths of 16.97 ± 1.35 cm and 23.23 ± 0.49 cm, root lengths of 9.27 ± 0.32 cm and 15.57 ± 1.00 cm, leaf areas of 84.10 ± 19.24 cm² and 87.98 ± 33.11 cm², and no leaves were 10.0 ± 0.58 and 8.0 ± 0.52 for lettuce leaves and radish, respectively. This study demonstrates the potential of utilizing selected Bacillus spp. and Aspergillus spp. consortia as eco-friendly biofertilizers to replace chemical fertilizers. The microbial formulations significantly improved plant growth, offering a sustainable solution for agricultural productivity.