Alleviation of Drought Stress in Faba Bean Using Humic Acid and Inoculation with Plant Growth Promoting Rhizobacteria

Drought is one of the major limitations to agricultural productivity worldwide and is likely to increase. This work is conducted to study the role of plant growth-promoting rhizobacteria (PGPR) inoculation in combination with humic acid as a foliar application for alleviation of drought stress on faba bean productivity. The inoculation of PGPR with humic acid as a foliar application can save half of the fertilizer requirements as well as reduce crop water requirement to 75% ETC without non significant reduction of faba bean yield. Faba bean inoculated with PGPR combined with humic acid and 50% inorganic NPK had higher microbial enzymes activities, nutrient uptake, and vegetative growth characteristics as well as it had a lower stress indicator (proline content) compared to control. Therefore, it can be relied upon to enhance the growth of faba bean, increase its productivity, while reducing its water requirements, and thus reducing production costs under drought stress.