INTERACTIVE EFFECTS OF N FERTILIZATION AND BRADIRHIZOBIA JAPANICUM ON AGRONOMICAL TRAITS OF SOYBEAN IN SALT AFFECTED SOILS

Abstract

Soil salinity has enormous negative impact on crop productivity leading to food insecurity and malnutrition, especially in arid regions. The aim of this study was to elucidate the interactive effects of different N fertilization rates and Bradyrhizobium japonicum (Kirchner) on agronomic traits of soybean [Glycine max (L.) Merr.] in saline soils (EC 5.8 dS m-1). Field experiments were conducted during the summer seasons of 2018 and 2019 to evaluate the effects of various N fertilization rates such as no fertilization (control), N0Р90К60, N30Р90К60, N60Р90К60 individually and in tandem with B. japonicum as a seed bioinoculant. The experiment in a split-plot design, N fertilization as the main plot, the seed inoculation as the sub-plot was set up in three replicates. Soybean growth, nutrients uptake and yield parameters increased with increasing N fertilization rate, however, the effect was more pronounced with the seed inoculation. Averaged over the cropping seasons, yield was higher by 20.4%, 19.0%, 34.1% and 6.1% in the inoculated treatments of no-fertilization, N0Р90К60, N30Р90К60, N60Р90К60, respectively as compared to the similar fertilization treatments without the seed inoculation. The fertilization rate of N30Р90К60 with B. japonicum inoculation was recommended due to the high soybean yield and quality seeds as the crucial components of sustainable agricultural production under salt-stressed field conditions.