Crop Diversification as a Catalyst for Soil Health: Correlation with Edaphic Fauna and Humic Fractions in the Pampa Biome

The present study aimed to evaluate the influence of distinct plant arrangements, established in No-Till Systems (NTS) for a period of two years, on the edaphic fauna and the quality of soil organic matter (SOM) in the Pampa Biome. The experimental design compared five treatments with an increasing gradient of plant diversity, ranging from fallow/monoculture (T1) to complex intercrops (T4 - Forage Radish + Ryegrass, and T5 - Vetch). The methodology employed included the evaluation of edaphic fauna, comprising earthworm counting and mesofauna diversity, and the characterization of SOM through chemical fractionation of humic substances and Fourier-Transform Infrared Spectroscopy (FTIR). The obtained results indicated that the systems with greater diversity (T4 and T5) promoted a significant increase in earthworm abundance and mesofauna richness. This intense biological activity correlated with a greater stabilization of carbon in the soil. The FTIR analysis, although confirming the continuous input of fresh material (evidenced by the aliphatic bands at 2920 cm⁻¹), complemented the chemical fractionation, which demonstrated the highest concentrations of the humin fraction (considered the most stable part of SOM) in treatments T4 and T5. This biological synergy shows that the edaphic fauna, stimulated by plant diversification, acts as a catalyst for the transformation of organic matter from labile to more persistent forms. It is concluded that crop diversification constitutes an essential biological trigger for the formation and accumulation of stable organic matter in Pampa Biome soils under NTS, being a crucial factor for mitigating degradation and promoting soil health.