Influence of Growth Promoting Rhizobacteria and Organic Matter on the Concentration of Micronutrients of Spinach in a Calcareous Soil Affected by Salinity

In order to investigate the effect of sodium chloride application, organic matter sources and growth promoting bacteria on fresh and dry matter yield and concentration of micro nutrients in shoot of spinach, a factorial experiment was conducted in a completely randomized design with three replications. The treatments were sodium chloride (control (S0), 2 (S2) and 4 (S4) g Na Cl kg-1 soil), organic matter (control (OM0), 0.5% and 1.0 % rice husk and 0.5% and 1.0 % rice husk biochar, w/w)  and PGPR bacteria (without and with bacteria). Results showed that application of 2 and 4 g salt kg-1 of soil slightly increased iron concentration of aerial part, while Cu concentration increased by 48.10% and 48.32%, respectively. However, Zn and Mn concentrations decreased. Plant yield was not affected by salinity, probably due to the osmotic adjustment resulting from gradual increase in salt addition. Application of organic matter sources increased spinach fresh and dry weight, and Fe, Zn, Cu and Mn concentrations. Inoculation with Pseudomonas fluorescence significantly increased fresh and dry weight as well as Fe, Zn, Cu, and Mn concentrations in aerial part, compared with the related control (without bacteria(. In conclusion, spinach (cv Virofly) very well tolerated gradual addition of salinity; and application of organic matter with growth promoting bacteria increased micronutrients concentration and growth of spinach in a calcareous soil affected by salinity.