Combined effects of pyroligneous acid dilutions and Bacillus subtilis UPMB10 on growth and yield of dwarf long bean (Vigna sesquipedalis)

The application of pyroligneous acid (PA) and UPMB10 (Bacillus subtilis) can improve the growth and yield of dwarf long bean (DLB) without affecting the environment. PA commonly derived from charcoal production as a by-product. Meanwhile, UPMB10 is a plant growth-promoting rhizobacterium (PGPR) isolated from oil palm root. Previous studies investigated the effects of UPMB10 inoculation and PA separately, and no research examined their combined outcome on crops. Therefore, an experiment was conducted to determine the PA’s influence on the young DLB seedling growth and the combined effect of PA and UPMB10 on the growth and yield of the DLB plant. The study investigated the effect of PA dilutions (v/v), control (water), 1:600 (P600), 1:400 (P400), and 1:200 (P200) and UPMB10 inoculation (uninoculated and inoculated) on the growth and yield of DLB. From the study, UPMB10 did not significantly improved the growth and yield of DLB. However, the PA effect was significant toward the yield production, where P400 had significantly promoted the DLB yield by increasing the total yield dry weight, which was positively correlated with the total number of DLB pods. For future research, an investigation on different application timing between PA and UPMB10 could prevent the potential negative impact of PA toward UPMB10 with reduced rates of chemical fertilizer and type of soil used.