Mesorhizobium inoculation and Water–nitrogen regimes enhance Potato–chickpea intercropping performance and Rhizosphere microbiome diversity
摘要
Increasing water scarcity poses significant threats to crop production and agricultural sustainability. Water deficit and the environmental impacts of synthetic nitrogen fertilization necessitate the development of sustainable cropping systems that enhance resource use efficiency while mitigating climate and economic risks. This study investigates the effects of Mesorhizobium ciceri inoculation (CMG6 strain (SI-DP 40653)), varying water–nitrogen regimes, and a potato-chickpea intercropping system (IC) on plant performance, metabolic responses, rhizospheric microbial diversity. Field trials, located in northeastern Tunisia, showed that IC combined with efficient M. ciceri inoculation significantly outperformed sole cropping (SC) across all physiological parameters. Under standard conditions, this synergy bolstered chickpea biomass and photosynthetic capacity. Notably, under reduced nitrogen input, inoculated intercropping (IC) boosted chickpea shoot biomass by more than twofold compared with sole cropping (SC). Intercropping also improved drought resilience, reducing stress-induced metabolic decline by approximately 40% relative to monocropping systems. Secondary metabolite production was stimulated, with higher accumulation of polyphenols and tannins observed particularly under reduced nitrogen conditions in inoculated systems. Additionally, intercropping improved potato productivity under low-nitrogen conditions while maintaining stable yields under drought stress. Metagenomic analysis showed that water stress accounted for approximately 22% of microbial community variation. However, intercropping and inoculation reshaped rhizosphere communities by enhancing the abundance and diversity of beneficial bacterial groups, particularly Bacilli, and buffering drought-induced shifts. These results emphasized the synergistic benefits of IC and Rhizobium inoculation in improving crop productivity, stress resilience, and soil health while reducing reliance on synthetic inputs.