Straw-returning of Triticale to field improved the yield of foxtail millet efficiently by modulating soil physicochemical traits and fungal microbiome assembly

Green manure-crop rotation systems are effective management practices for maintaining soil health and enhancing crop yield. However, the influence of various green manure-millet rotation systems on soil properties, fungal community structure, and millet yield in the North China Plain remains undetermined. In this study, three types of green manures with foxtail millet rotation experiment were conducted. The physico-lchemica indexes, millet yield and soil fungal community characteristic were detected. Our findings suggest that three green manure-millet rotation systems increased millet yield compared to millet-winter fallow (Si-Le). Among them, the Triticale-millet rotation (Si-Ts) showed the highest yield increase, with a rise of 46.16% in 2021 and 85.7% in 2022. In 2021, compared with Si-Le, the organic matter (OM) in Si-Ts increased by 17.86%, and the available phosphorus (AP) rose by 113.82%. In 2022, in contrast to Si-Le, the alkali-hydrolyzed nitrogen (AHN) in Si-Ts increased by 17.68%, the available phosphorus (AP) by 37.56%, and the available potassium (AK) by 12.56%. Additionally, Si-Ts exhibited the highest diversity of soil fungi and the greatest relative abundance of beneficial genera from the dominant phylum Ascomycota and Mortierellomycota. Moreover, Green manure rotations (particularly Si-Ts) alleviate these constraints by simultaneously augmenting microbial diversity (driven by OM/AK/AHN) and crop yield (driven by AP/OM). Overall, the Triticale-millet rotation is a feasible practice for improving soil conditions, maintaining soil microbial balance, and ensuring high yields of millet. Our findings offer theoretical support for green manure-crop rotation in influencing the soil environment and the sustainable development of the millet industry in the North China Plain.