Response of soil bacterial community to repeated applications of carbendazim

The effect of repeated carbendazim applications on functional diversity of culturable microorganisms and bacterial community composition was studied under field conditions. The functional diversity of soil culturable microbial community (Shannon index, H′) reduced significantly (P<0.05) after the first introduction of carbendazim at levels of 0.94, 1.88 and 4.70 kg active ingredient (a.i.) ha−1 and then recovered to that in the control with subsequent applications. An evident (P<0.01) difference in the bacterial community composition was observed after the second carbendazim application by Temperature Gradient Gel Electrophoresis (TGGE) analysis of 16 S rRNA genes amplified from treated and control soils, which remained after the third and fourth treatments. Our results indicated that repeated carbendazim applications have a transient harmful effect on functional diversity of soil culturable microbial community and result in an alteration in bacterial community composition largely due to one species within the γ-proteobacterium.

► Effect of repeated carbendazim applications on microbial functional diversity. ► Effect of repeated carbendazim applications on bacterial community composition. ► A transient harmful effect on culturable microbial functional diversity occurs. ► Repeated applications induce an alteration in bacterial community composition. ► Structural alteration is largely due to one species within the γγ-proteobacterium.