Influence of Rice-Husk Derived Biochar and Growth Promoting Rhizobacteria on the Yield and Chemical Composition of Spinach in Soil under Salinity Stress

In order to investigate the effects of application of sodium chloride, organic matter, and growth promoting bacteria on fresh and dry shoot weights and also concentration of some nutrients in aerial parts of spinach, a factorial experiment was conducted in a completely randomized design with three replications.  The treatments consisted of three levels of sodium chloride (control (S0), 2 (S2) and 4 (S4) g Na Cl kg-1 soil equivalent to 0.7, 8 and 16.8 dS/m, respectively), five levels of organic matter (control 0%(OM0), 0.5% (RS0.5) and 1% (RS1) % rice husk and 0.5% (Bi0.5) and 1% (Bi1) % rice husk biochar, w/w)  and two bacterial levels i.e. without (P0) and with bacteria (P1). Results showed that increasing salinity levels significantly increased spinach dry weight, but significantly decreased concentrations of N, P, Ca and Mg in aerial part, while concentration of Na increased. With the use of organic matter sources, fresh and dry weights of spinach shoot and con fluorescence [H1] centration of all nutrients increased significantly. Also, addition of Pseudomonas fluorescence significantly increased fresh and dry weights and concentration of nutrients of spinach aerial part .According to the results obtained in this study, it can be concluded that the use of organic matter as a soil amendment and rich source of nutrients can greatly increase concentration of nutrients in spinach. Also, addition of Pseudomonas fluorescence as a biofertilizer can improve spinach growth and increase concentration of some nutrients in spinach aerial part under salinity conditions. Application of organic matter and bacteria in salinity-free conditions increased concentration of nutrient and yield of plant. In general, further investigations under field conditions are necessary to verify the results of the present study.  [H1]?