The Stimulatory Effects of Humic Substances and Microbial Inoculants on Cropping Performance of Guava (Psidium guajava L.) cv. Lalit in Meadow Orcharding System

Abstract

Foliar application of humic acid along with bio-inoculants in 4-year-old inarched guava cv. Lalit in meadow orcharding system was carried out. Foliar application of humic acid @ 30 and 60 mL/L at bud burst to flowering stage and bio-inoculants (Phosphorus solubilizing bacteria (PSB) @ 10 mL/plant + Azotobacter chroococcum@ 10 g/plant, and PGPR @ 25 mL/plant + AM fungi @ 25 g/plant) in rhizosphere along with @ 90 and 80 percent of the recommended dose of fertilizers (RDF) of NPK (360:740:200 g/tree) was carried out. Application of humic acid applied at 60 mL/L along with PSB and A. chroococcum at 10 mL/plant beside 80 per cent of RDF-NPK inferred positive impact on growth traits throughout the winter season. This combination recorded vital increase in percent fruit set with reduced fruit drop. Fruit yield was 2.9 times higher over control. Fruit quality with this conjoint application also improved. Soil microflora recorded as actinomycetes, A. chroococcum, PSB and AM fungi were improved. This combination also exhibited significant increase in leaf N, P and K contents in the meadow geometry plant–soil interface. Maximum cumulative variance of 97.9 percent in PCA based on the Eigenvalue (>1) was recorded. Maximum total cumulative variance for vegetative growth characteristics, flowering and yield contributing traits in guava under meadow plantations were observed in PC4. Our findings emphasized the promising effects of humic acid and bio-inoculants on improvement of growth, nutrient profiling and biological activity at reduced application of NPK.