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• Multi-stubble planting induced negative PSF, mitigated by straw amendments. • Rhizosphere fungi governed PSF dynamics via deterministic processes. • Rhizosphere fungal guilds shifted PSF positively, especially the pathotrophs. • Guild effects were mediated via soil inorganic N availability and multifunctionality. • Synergistic stubble and straw management optimize PSF for sustainable agriculture. Plant-soil feedback (PSF) processes represent fundamental drivers of ecosystem succession, yet the dynamic characteristics and regulatory mechanisms under combined multi-stubble planting and straw amendment systems remain insufficiently understood. In this study, a controlled greenhouse-based PSF experimental system incorporating multi-stubble planting (0, 1, 3, and 5 stubbles) and gradient straw amendments (0, 40%, 60%, 80%, and 100%) of alfalfa ( Medicago sativa L.), along with a long-term maize monoculture control (5 stubbles), was established to investigate the soil legacy effects on subsequent maize ( Zea mays L.) growth performance. By assessing the variation patterns of root-associated fungal communities (rhizosphere vs. endosphere), and bulk soil physicochemical properties of maize, we elucidated microecological mechanisms governing PSF dynamics. Our results showed that compared with straw amendments, multi-stubble planting of alfalfa exhibited a greater impact on the growth performance of subsequent maize. Increasing frequency of multi-stubble planting of alfalfa shifted maize PSF effects (calculated as ln-transformed maize total biomass differences between conspecific and heterospecific soils) toward negative feedback, while straw amendments effectively mitigated this trend. Compared to root endophytic fungal community, maize rhizosphere fungal community were predominantly governed by deterministic processes, serving as a key biotic predictor of PSF. Furthermore, rhizosphere fungal guilds (saprotrophs, symbiotrophs, and pathotrophs) actively modified the PSF dynamics, particularly through pathogenic guilds, promoting a shift toward positive feedback effects. Such mediation processes demonstrated significant correlations with soil inorganic nitrogen availability and multifunctionality. These findings provide important implications for advancing resource-efficient ecological agriculture through targeted management of rhizosphere microbial guilds and synergistic improvement of nutrient cycling efficiency.
He et al. (Wed,) studied this question.