Augmentation of Plant Growth Attributes, Soil Physico-Chemical Properties and Microbial Population in Custard Apple cv. Balanagar in Response to Azospirillum brasilense and Vermicompost Application in Humid Zone of South Eastern Rajasthan, India

Abstract

ABSTRACT Field experiments were conducted for two successive seasons July 2018 to November 2018 and July 2019 to November 2019 at the Fruit Instructional Farm, Department of Fruit Science, College of Horticulture and Forestry, Jhalawar district under Rajasthan state of India. The experiment consisted of different treatments of Azospirillum brasilense (AZS) and Vermicompost (V.C.). It was laid out in a Randomized Block Design with three replications. The 16 different treatment combinations of AZS and Vermicompost were applied to soil canopy of custard apple cv. Balanagar plants during first week of July 2018 and July 2019 in canopy rhizosphere of black vertisols in custard apple plants. Among different treatment combinations, T10 treatment consisting of AZS @ 50 g + V.C. @10 kg/plant was found relatively better over all other treatments with respect to most of the plant growth characteristics, including soil health properties and microbial population density in soil availability in canopy of custard apple cv. Balanagar plants. The pooled results of two years revealed comparative better plant growth parameters viz. rootstock girth (74.20 mm), scion girth (61.52 mm), plant height attribute (3.46 m), number of nodes per shoot (13.00), number of nodes per branch (86.17), number of shoots per branch (26.00), number of shoots per plant (151.00) have shown augmenting response in improvement of plant growth parameters under T10 treatment (AZS @ 50 g + V.C. @ 10 kg /plant) in custard apple cv. Balanagar plants. However, key soil parameters concerning bulk density (1.32 g/cm3), soil pH (7.39), and electrical conductivity (0.46 dS m−1) reduced significantly under T10 treatment over other treatments. The soil physico-chemical properties especially change in porosity (55.04%), organic carbon (0.55%), available nitrogen content (350.55 kg/ha), available phosphorous content (46.51 kg ha−1) and available potassium content (322.34 kg ha−1), bacterial population (26.67 cfu g−1), fungi population (15.00 cfu g−1) and actinomycetes population (10.00 cfu g−1) have shown tremendous response in improvement of soil parameters under T10 treatment (AZS @ 50 g + V.C. @ 10 kg /plant) with respect to overall soil health.