In Vitro Sensitivity of <Emphasis Type="Italic">Rhizobium</Emphasis> and Phosphate Solubilising Bacteria to Herbicides

Nitrogen fixing bacteria, rhizobia and phosphate solubilizing bacteria (PSB) are the commonly applied microbial inoculants in grain legumes (Pulses). It is important to apply herbicides to control weeds in order to augment yield of the crop. The herbicides may however, be incompatible with the microbial inoculants. This study compared the effect of the recommended pre-plant incorporated herbicide, fluchloralin (20.25 × 10⁴ ppm) and pre-emergence herbicide, pendimethalin in two doses (9 × 10⁴ and 15 × 10⁴ ppm) on the growth and survival of mungbean Rhizobium and PSB, under laboratory conditions. These herbicides were also used under field conditions in conjunction with biofertilizers (R, PSB) to improve grain yield of mungbean. It was found that fluchloralin (20.25 × 10⁴ ppm) and the lower dose of pendimethalin (9 × 10⁴ ppm) had no adverse effect on growth of Rhizobium and PSB. The higher dose of pendimethalin (15 × 10⁴ ppm) was safe on PSB but it imposed a retarding effect on the growth of Rhizobium.