Rangelands and silvopastoral systems of the middle Atlas are under a heavy pressure, which led to pasture degradation, invasion by non-palatable and toxic species and edaphic aridification due to the regression of the global vegetation cover. In this situation, the introduction of multipurpose leguminous shrubs, such as Bituminaria bituminosa (L.) Stirton, commonly known as bituminous clover, could be a promising socio-ecological alternative for the rehabilitation of these degraded areas. The application of biofertilizers like plant growth promoting rhizobacteria especially phosphate solubilizing bacteria (PSB) can ensure a successful installation of this plant in the selected degraded areas. The main objective of the present work is to produce well-inoculated seedlings using the best efficient PSB strains in the greenhouse to increase their ability to resist to environmental constraints once transplanted to the field in the central Middle Atlas.

Aims: The study aimed to evaluate the effect of inoculation by different rhizobacteria on Bituminaria bituminosa plants grown under greenhouse conditions. Study Design: An experimental study. Place and Duration of Study: The study was carried out at the Department of Biology (Environment and valorization of microbial and plant resources Unit), Faculty of Sciences, Moulay Ismail University-Meknes, from November 2019 to February 2020. Methodology: Eleven species and/or isolates belonging to Rhizobium genus are used to inoculate B. bituminosa plants; similarly, fresh and dry crushed nodules previously collected from B. bituminosa shrubs are tested. The bacterial inoculation effects are evaluated through the estimation of inoculated plants’ fresh and dry shoots weight, root dry weight, total nitrogen, nodules number and fresh weight in comparison to non-inoculated plants. The infectivity and efficiency of the bacteria and the biological nitrogen fixation are also evaluated. Results: The results enable us to select the infective strains on the basis of their positive effect on growth and total nitrogen, in order to produce inoculum for B. bituminosa. Efficiency and biological nitrogen fixation are also very high compared to the control, especially with the B.b1 strain isolated from Bituminaria bituminosa and identified as Rhizobium tibeticum. The fresh nodules crushing is also very efficient. as inoculant. Conclusion: The use of symbiotic complex as Rhizobium tibeticum – Bituminaria bituminosa or an inoculum produced from fresh nodules are an eco-friendly alternative for the design of sylvo-pastoral systems ensuring increased soil fertility, fodder productivity and sustainable agroforestry.