Assessing the compatibility of pre- and post-emergence herbicides with plant growth promoting rhizobacteria on performance of soybean

Abstract

The study was conducted to know the compatibility of different herbicides recommended for soybean with plant growth promoting rhizobacteria (PGPR) including the native strain of Rhizobium so that the tolerant microbes could be used as a potential herbicide tolerant microbial culture to support the soybean crop nutritionally and on the growth performance of the soybean ( Glycine max L. Merill). In this study, the soybean crop was inoculated by cultures of Bradyrhizobium daqingense, Paenibacillus polymyxa and Bradyrhizobium japonicum . As recommended herbicides for soybean, pre-emergence herbicides diclosulam and pendimethalin were sprayed to the soybean plant 52 ppm/ha and 6 ppm/ha, respectively at 5 days after sowing. Post-emergence herbicides propaquizafop and imazethapyr were sprayed to the soybean plant 1.2 ppm/ha and 2 ppm/ha, respectively and their cocktail mix 4 ppm/ha at 18 days after sowing. The experiment was laid out in a completely randomized design with eighteen treatments repeated three times on a soybean crop (cv: JS-9560 ). The results of the investigation revealed that pendimethalin was comparatively more compatible with PGPRs than diclosulam under pre-emergence herbicide category. In case of post-emergence herbicides, propaquizafop was comparatively more compatible with PGPRs, than imazethapyr and cocktail mix of propaquizafop + imazethapyr. The propaquizafop was found safe herbicide to produce maximum biomass yield of soybean at 50 days after herbicide application (DAHA). The nodulation behavior was found significantly less affected by all the herbicidal application in presence of Bradyrhizobium daqingense .