Responses of some agronomical characteristics of faba bean (Vicia Faba L.) to biofertilizers under water deficit stress

Iran’s climate is mostly arid and semi-arid, where water availability is a major problem in crop production. In regions where water scarcity is the principal limiting factor for cultivation, farmers are interested in growing crops that are able to adapt to drought conditions. Bio-fertilizer has been identified as an alternative to chemical fertilizer in sustainable farming. Organisms that are commonly used as biofertilizers component are nitrogen fixers (N-fixer), potassium solubilizer (K-solubilizer) and phosphorus solubilizer (P- solubilizer), or with the combination of molds or fungi increased growth and yield plants. Therefore, the aim of this study was to investigate the use biofertilizer in drought stress on several agro-morphological and yield characteristics of faba bean under field condition.
In order to study the effects of different irrigation levels and biofertilizers on yield and yield components of faba bean, a field experiment was conducted as split plot based on randomized complete block design with three replications at the a farm located in West Azerbaijan province - city Nagadeh, Iran during growing season of 2013-2014. The main plots were allocated to irrigation levels (Irrigation after 50 mm (control), 100 mm (moderate water stresses) and 150 mm (severe water stresses) evaporation from class A pan) and sub-plots were allotted to biofertilizers (Azotobacter and Barvar Phosphate-2, Azotobacter Barvar Phosphate-2 and control).
Results showed that irrigation had significant effects on Plant height, number of pod per plant, number of seed per pod, 1000- seed weight, biological yield and seed yield but the interactions between irrigation levels and biofertilizers on any of the traits under study were not significant. In comparison severe stress (lowest yield and yield components), a non-stress conditions, on Plant height, number of pod per plant, number of seed per pod, 1000- seed weight, biological yield and seed yield were decreased up to 21.90, 39.83, 28.83, 26.15, 33 and 38 %, respectively. Among treatments, combined usage of biofertilizers showed the greater increasing in studied traits than individual consumption.
The results generally indicated that the inoculation with biofertilizers could not reduce the adverse effects of drought stress and could not effect on increasing of yield significantly. Therefore, to achieve optimal performance in arid and semi-arid areas, irrigation at all stages of faba bean of development recommended.