Foliar application of Azatobactor chroococcum increases leaf yield under saline conditions in mulberry (Morus spp.)

In this study, the effect of two nitrogenous fertilizers such as urea and the bacterial bio-fertilizer ‘Azatobactor chroococcum’ on growth and development along with leaf quality was studied under various levels of NaCl in mulberry. Performance of four mulberry varieties, two tolerant and two susceptible to salt, were studied in pot culture. NaCl at different concentrations (0.0%, 0.25%, 0.50%, 0.75% and 1.00%) was applied to the pots and the required EC (1.58, 6.50, 10.10, 14.10 and 19.20 dS m−1, respectively) was maintained through regular monitoring of the soil saturation extract. Urea was applied to the soil while the bacterial bio-fertilizer A. chroococcum was applied in two different ways such as soil application and spraying on the leaves. The results showed that salinity affects the growth and development of mulberry, however, application of nitrogenous fertilizer mitigates the harmful effects of salinity significantly in both salt tolerant and susceptible varieties. Significant variations on the response of the varieties to all treatments and their interactions were also observed. Foliar application of bacterial fertilizer was found better than soil application. Both biochemical and morphological characters showed significant level of improvement when A. chroococcum was sprayed on the leaves.