RELATIONSHIPS AMONG SOIL FERTILITY, RHIZOSPHERIC MICROBIOME, AND NEMATODE INCIDENCE IN COMMON BEAN PRODUCTION SYSTEMS

Common bean (Phaseolus vulgaris L.) is strongly influenced by the physical, chemical, and biological conditions of the soil, requiring management practices that promote soil health and production stability. Among these practices, cover crops and plant growth-promoting microorganisms have been adopted to enhance soil fertility and modulate the rhizospheric microbiota. This study evaluated, over three winter seasons, the effects of different cover crops and bioinputs on soil attributes, microbial and nematode communities, and the agronomic performance of irrigated common bean. The experiment followed a randomized block design in a 5 × 3 factorial scheme, combining five cover crops (fallow, millet, buckwheat, and two multispecies mixes) and three microbial managements (Embrapa, Partner, and Control), with four replications. Evaluations included cover crop biomass production, chemical and microbiological soil attributes, soil and root nematode populations, enzymatic activity, and common bean yield components. Biomass production varied significantly among cover crops, with higher values for millet and multispecies mixes. Soil analysis indicated specific effects of the inoculants on P, K, Zn, and Cu, as well as marked seasonal variations, especially associated with water availability. Microorganisms affected populations of Rotylenchulus reniformis and Pratylenchus brachyurus, whereas cover crops showed limited short-term effects on the nematode community. Common bean yield ranged from 1.24 to 2.09 t ha⁻¹, being more strongly influenced by microbial treatments and seasonal conditions than by cover crops; the Partner treatment showed the best productive performance, providing an average yield increase of 4.97% (79.6 kg ha⁻¹) compared to the control treatment. The results demonstrate that cover crops promote important environmental improvements, but immediate agronomic responses are modest. Bioinputs, in turn, exhibit specific and environment-dependent effects. The strong influence of seasonal conditions reinforces the need for multiyear evaluations to fully understand edaphic and biological dynamics.