Rhizosphere stochiometry, fruit yield, quality attributes and growth response to PGPR transplant amendments in strawberry (Fragaria X ananassa Duch.) growing on solarized soils

Plant Growth Promoting Rhizosphere microorganisms transplant amedements were tested for improving growth, yield, quality traits, runner production and rhizosphere stochiometry of strawberry cv. Chandler. The plants were grown on solarized and non-solarized organic matter rich soil. Exogenous root inoculation of six PGPR inoculants viz., Pseudomonas florescence, Bacillus subtilis, Azotobacter chroococcum, K-mobilizing bacteria and AM fungi were carried out in different combinations in a randomized completely block design with three replicates. The solarization was done with transparent plastic sheet. Application of 250 g PGPRs consourtium along with soil solarization significantly improved vegetative growth traits, rhizosphere microbial count, fruit number, cumulative yield, fruit quality traits as compared to non-solarized (natural) conditions. Root soil ratio of resident microbes at 15 cm depth was also worked out in the rhizosphere zone and non-rhizosphere zone. The data suggested an increased rhizosphere acid- and alkaline phosphate and dehydrogenase enzyme activity can be used as a good indicator of phosphorus nutrition in solarized organic soils compared to non-solarized (natural) soils. The results suggested that PGPR inoculations could alleviate the deleterious effects of soil borne microbial population on the phenological and pomological attributes of strawberry plants under organic growing solarized soils. Root inoculation with PGPR probiotics significantly affected leaf nutrient concentration in terms of DOP and Sigma DOP indexes which showed an increase in N, P, K and Mg concentration in the leaves in solarized plots compared to natural plots. Principal component analysis induced the differences at various PGPR probiotics applied has identified maximum of the total variance based on the Eigen value (> 1) and explained 65.38% (PC1), 79.68% (PC2), 88.05% (PC3) and 92.67% (PC4) of the cumulative variance. PC4 accounted for highest total cumulative variances among fruit phenological, morphometric and generative potential strawberry traits. The study indicated PGPR probiotics coupled with soil solarization as a promising technology to maintain healthy rhizosphere, and as an alternative to chemicalised farming of strawberry to enhance quality production in calcareous soils of Shiwalik foothills of north-west Himalayas.