MUTHURAJU, RLAVANYA, S M2023-01-132023-01-132022-12-06Th-13358https://krishikosh.egranth.ac.in/handle/1/5810192050The present study was carried out to understand the effect of different humic acid basedliquid nutrient formulations and humic acid coated fertilizers on soil biological properties,growth and yield of paddy, maize and tomato under field condition. Application of the humicacid based liquid nutrient formulations i.e., Product 1 @ 2.0 l/acre stimulated significantlyhigher population of free-living nitrogen fixers in paddy (9.64×104 CFU/g), maize (9.69×104CFU/g) and tomato (9.99×104 CFU/g) rhizosphere. Further, highest dehydrogenase enzymeactivity in paddy (124.52 μg TPF/g/h), maize (126.07 μg TPF/g/h), tomato (151.25 μg TPF/g/h)and microbial biomass carbon and nitrogen in paddy (402.43 and 46.95 μg/g of soil), maize(455.26 and 53.11 μg/g of soil) and tomato (446.41 and 52.08 μg/g of soil) rhizosphere wasobserved in treatment that received the Product 1 @ 2.0 l/ac. Application of humic acid coatedfertilizer recorded increased plant height (128.19 cm), number of tillers (24.81/plant), numberof panicles per plant (19.38), grain yield (31.76 q/ha) in paddy, highest seed weight at harvest(124.94 g), grain yield (64.91 q/ha) in maize and highest plant growth parameters, highestnumber of fruits per plant(19.52), fruit weight per plant (8.70 kg) and fruit yield (66.13 q/ha) in tomato. It is evident from the data obtained in the field experiment involving paddy, maize andtomato that application of humic acid based liquid nutrient formulation product 1 @ 2.0 l/acreenhanced the biological properties of rhizosphere soils, growth and yield of these cropscompared to the soil which received inorganic fertilizers.EnglishThesis