Crop rotation, cover crop mix, and multifunctional rhizobacteria for the sustainable development of soybeans

Soybean monoculture (Glycine max) and second-crop corn succession in the Cerrado reduce soil quality and compromise long-term productivity. Adopting conservation practices such as crop rotation, cover crops, and multifunctional rhizobacteria is essential for sustainable soybean cultivation in the region. This study aimed to determine the effect of mixes of cover crops grown in the second crop in rotation with upland rice and co-inoculation of soybeans with multifunctional rhizobacteria on the physical, chemical, and biological quality of the soil and the nutrient accumulation, biomass production, production components, and yield of the soybean crop. The experiment was conducted in a randomized block design, arranged in a 7x2 factorial scheme, with 14 treatments and four replications. Treatments included five cover crop mixes and two fallows (rice/fallow/soybean and soybean/fallow/soybean), with or without co-inoculation of seeds with Bacillus sp. (BRM 63573) and Serratia marcensces (BRM 32114). Rotation with upland rice and cover crop mixes provided higher P and Zn content in the soil, higher activity of the β-Glycosidase enzyme, lower density, better total porosity, lower incidence of phytopathogenic fungi Fusarium solani and Rhizoctonia solani and greater biomass production, greater macro and micronutrient content in the aerial part, greater number of pods per plant and grain yield of the soybean crop concerning the areas that remained fallow. Fallow 2 (soybean/fallow/soybean) provided the worst results for most of the analyzed variables. Co-inoculation provided higher soil microporosity, lower density of the phytopathogenic fungus (Fusarium oxysporum) in the soil, and greater biomass production and nutrient accumulation in the shoot of soybean plants compared to treatment without co-inoculation.