Effect of Cell Free Microbial Bio-Stimulant on Growth, Yield and the Microbial Activity of Tomato (Solanum lycopersicum L.) Grown in Vertisol

A field experiment was conducted to find out the effect of a cell-free microbial biostimulant on growth, yield, and the microbial activity of tomato (Solanum lycopersicum L.) grown in a field during the rabi season (December–April) of 2021–22 at the Instructional Cum Research Farm, College of Agriculture, IGKV, Raipur, Chhattisgarh, India. Pant-3 variety of tomato was used for the experiment, which was spaced in 45×60 cm. The experiment consists of seven treatments, viz., six levels of cell-free microbial bio-stimulant (control, 0.125 L ha-1, 0.25 L ha-1, 0.50 L ha-1, 0.63 L ha-1, 1.25 L ha-1, and 2.50 L ha-1), in combination with 100% Recommended dose of fertilizer (RDF), and was laid out in a randomised block design (RBD) with three replications. Data regarding the height of the plant, numbers of fruits (plant-1), yield (kg ha-1), dehydrogenase, and microbial activity were observed. The experimental result revealed that the application of a cell-free microbial bio-stimulant with a combination of 100% RDF was found to have a significant impact on the microbial population and dehydrogenase activity of soil, but that plant height, fruit number, and yield were not significantly affected. According to the performance of the crop and analysis of rhizosphere soil, it can be concluded that the cell-free microbial bio-stimulant @ 2.50 L ha-1 with soil application along with 100% RDF (120:80:80 kg ha-1 N:P:K) increases the soil microbial population, i.e., bacteria, actinomycetes, and fungi, and also improves the quality of the soil.