Rhizobia inoculation increases pea grain yield: an overview and challenges

The aim of this study was to evaluate the contribution of inoculation with microorganisms, mainly rhizobia, on pea (Pisum sativum) production using a systematic literature review approach and a comparative analysis of grain yield to provide information to fill gaps in nontraditional regions of cultivation for this legume. A systematic search strategy was implemented, targeting papers published in scientific journals accessible through the Web of Science® (WoS) database spanning from January 1990 to April 2022. The search terms "Pisum sativum," "inoculation," and "strain" were used. The differences between the pea grain yields from plants inoculated with nitrogen-fixing microorganisms and those from noninoculated plants (control) were analyzed using thirteen field-scale studies. Overall, pea inoculation/coinoculation promoted a greater grain yield (3118 ±210 kg ha-1) than noninoculation (2338± 127 kg ha-1), showing the importance of biological nitrogen fixation for legume crop production. In the pursuit of reducing pea production costs, emphasis has been placed on inoculation, highlighting the importance of comprehending the symbiotic relationship between peas and Rhizobium. Furthermore, this research aimed to explore the interaction between Rhizobium and selected microorganisms known to enhance plant growth to identify optimal combinations to boost pea productivity.