Intercropping with alfalfa and co-inoculation of AMF and PGPR improve growth, yield, grain bioactive quality, and soil fertility of barley

ABSTRACT The use of intercropping systems and beneficial microorganisms to improve the performance of crops constitutes a promising strategy. In this context, a pot experiment was conducted to evaluate the effects of intercropping and inoculation with arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) on the performance of barley and alfalfa plants and soil health. Three inoculation treatments (for both monocropped and intercropped plants) and the control were used: (1) AMF-inoculated plants; (2) PGPR-inoculated plants; (3) AMF+PGPR co-inoculated plants. Combining intercropping and AMF+PGPR co-inoculation improved shoot and root dry weight by 167% and 300% in barley and by 712% and 617% in alfalfa, respectively, compared to the controls. Similarly, in barley intercropped and inoculated with AMF+PGPR, the number of grains per spike and the thousand-grain weight were enhanced by 124% and 122%, respectively. Applying intercropping and co-inoculation of AMF+PGPR increased the protein, total phenolic, and flavonoid contents of barley grains by 99%, 132%, and 343%, respectively. The contents of soil nitrogen and phosphorus were improved by 387% and 270% in barley soil and by 359% and 212% in alfalfa soil, respectively, compared to monocultures.