Effects of cover crops and microbial inoculants in different farming systems on soil microbial communities and yield of maize

Abstract We studied the effects of cover crop treatments (fallow or cover crop) and microbial grain inoculation (control, arbuscular mycorrhizal fungi (AMF), and AMF + bacteria) on soil microbial diversity, community composition, and maize yield across four field sites characterized by different farming systems over two consecutive years. Farming system emerged as the dominant factor driving variations in microbial community composition and diversity. The highest AMF and bacterial diversities were observed in the organic system, while the conventional systems exhibited the lowest diversity. Soil properties and management influenced the microbial community in each field site, whereas weather conditions were less important, due to the proximity of the field locations. Microbial grain inoculation significantly increased maize yield in the high-fertility conventional field, while cover cropping improved yield in the organic and transitional fields. Our study demonstrates that the effects of microbial inoculation and cover cropping are profoundly context-dependent, highlighting the complex interplay between these treatments and field site characteristics, and agricultural management practices. By identifying the specific contexts in which inoculation and cover cropping yield tangible benefits, our study promotes a more targeted, systems-based approach to sustainable agricultural intensification.