Potassium depletion links to microbial richness loss and functional enrichment in Angelica sinensis rhizosphere under agrivoltaic systems

Background and aims In this study, we aimed to investigate the effects of photovoltaic panel shading on rhizosphere microbial communities of plants with distinct light requirements. Methods Citrus limon , Rhodomyrtus tomentosa , and Angelica sinensis were cultivated outside, between, and beneath photovoltaic panels, followed by amplicon sequencing and analyses of soil physicochemical properties and enzyme activity. Results The A. sinensis rhizosphere showed higher bacterial Chao1 index and lower fungal Chao1 index than those of C. limon and R. tomentosa , with enrichment for Lentilactobacillus . Available potassium (AK) was the strongest environmental factor driving variation in microbial community structure. AK contents were significantly lower in the A. sinensis rhizosphere (62.13 mg kg− 1 ) than in C. limon (284.59 mg kg− 1 ) and R. tomentosa (161.66 mg kg− 1 ) rhizospheres and exhibited significant negative correlations with Lentilactobacillus , Humicola , and Plectosphaerella . Functional prediction revealed reduced chemoheterotrophic functions and increased pathogen-associated functions in the A. sinensis rhizosphere. Fungal functional guild analysis indicated enrichment of endophyte–plant pathogen-associated groups and endomycorrhizal fungi. Responses to shading were stronger for fungal than for bacterial communities and varied among plant species. Photovoltaic shading reduced soil pH, nitrate, and AK contents, while increasing acid phosphatase activity, ammonium nitrogen contents, and soil moisture. Conclusion Our findings highlight the strong associations of plant species and AK depletion with microbial restructuring under photovoltaic conditions, and the indirect linkage of photovoltaic panel positioning to microbial communities via alterations in soil moisture and pH conditions. These findings provide scientific guidance for crop selection and soil management strategies in agrivoltaic systems.