Yerba mate (Ilex paraguariensis A.St.-Hil.) is a native species of the subtropical and temperate regions of South America. In the Misiones province, in Northeastern Argentina, yerba mate is an impo...

Intensive land use in the Argentine Pampas has led to soil degradation, yet links between soil organic matter (SOM) composition, enzyme activity, and fungal communities remain unclear. This study compared contrasting ecoregions and land uses: pristine (PI), pasture (PA), crop rotation with cover crops (RO), and monoculture (MO). Infrared spectra showed that PI soils in Anguil had higher absorbance in hydroxyl/amine (3400 cm⁻¹: 0.90 ± 0.08) and carbonyl (1750 cm⁻¹: 0.52 ± 0.12) bands than MO soils (0.47 ± 0.30 and 0.35 ± 0.06; p < 0.05), indicating greater SOM diversity. Pergamino soils showed smaller differences, reflecting site-specific effects. Enzyme activities also responded to land use. In Anguil, xylosidase, β-1,4-N-acetylglucosaminidase, and phosphatase peaked under PI (40, 127, and 443 nmol g⁻¹ h⁻¹). In Pergamino, xylosidase and β-1,4-N-acetylglucosaminidase were higher under PA and PI, indicating enhanced microbial functionality under low disturbance. Fungal composition varied with land use and location: Mortierellomycetes dominated in Pergamino, while Leotiomycetes and Agaricomycetes were more abundant in PI and PA, and Dothideomycetes increased in MO and RO. Despite compositional shifts, fungal diversity changed little. Integrating chemical, biochemical, and molecular indicators revealed how land-use intensification modifies SOM and microbial processes in Pampas soils.

La producción de maní (Arachis hypogaea L.), establecida en una región caracterizada por suelos arenosos y naturalmente susceptibles a procesos de degradación, plantea un escenario donde las propiedades del recurso edáfico pueden experimentar modificaciones vinculadas a las condiciones de manejo. A su vez, a partir de su procesamiento industrial surge el interés por valorizar sus residuos, en particular la cáscara, como estrategia para una gestión sostenible del suelo. Este estudio evaluó el impacto de la aplicación de dos enmiendas orgánicas, ceniza y biochar derivados de cáscara de maní, sobre la fertilidad del suelo, su microbiota y el rendimiento del cultivo. Se implementó un ensayo en invernadero con cinco tratamientos (testigo, ceniza 1% y 3%, biochar 1% y 3%) durante tres años, midiendo parámetros químicos, microbiológicos, fenológicos y productivos. Los resultados evidenciaron que biochar incrementó el carbono orgánico (CO), nitrógeno total (NT), actividad enzimática (FDA) y biomasa microbiana (CBM y NBM), mejorando la dinámica de floración, el rendimiento y la biomasa aérea, con efectos positivos a lo largo del tiempo. En efecto, la aplicación del 3% de biochar produjo, en promedio, incrementos del 38% en CO y del 33% en NT en comparación con el suelo testigo. Por su parte, la adición de ceniza al 3% aumentó en un 20% el pH y en un 60% la conductividad eléctrica, aunque con efectos limitados sobre la biología del suelo y la productividad. El análisis de correlación indicó que las propiedades microbiológicas (FDA y NBM), estuvieron estrechamente asociadas al rendimiento a diferencia de las propiedades químicas tradicionales. Estos hallazgos resaltan la importancia de utilizar los parámetros biológicos para evaluar la sostenibilidad y productividad de los sistemas agrícolas. En conclusión, la incorporación de biochar derivado de cáscaras de maní representa una estrategia eficaz para mejorar la calidad biológica del suelo, optimizar el uso de nutrientes y mejorar la resiliencia de los cultivos.

Aims Crop rotations and cover crops influence the chemical and biological characteristics that define soil health, with the rhizosphere playing a crucial role in plant defense mechanisms. Soybean sudden death syndrome (SDS) caused by species of Fusarium , leading to substantial yield loss in major soybean-producing countries. The objective was to assess the long-term effects of crop sequences with different land occupations on SDS occurrence and soil microbial community composition. Methods Research was conducted over three agricultural seasons in a long-term field experiment on four crop sequences: full-season soybean monoculture (S-S); winter cover crop/full-season soybean (CC/S); full-season soybean - double-cropped wheat/soybean - maize (S-W/S-M), and winter cover crop/full-season soybean - double-cropped wheat/soybean - maize (CC/S-W/S-M). Incidence of soybean SDS (SDS-I) was measured as the percentage of plants exhibiting foliar symptoms. Soil microbial community composition was characterized through phospholipid fatty acid (PLFA) analysis. Additionally, soil organic carbon and nitrogen and, full-season soybean production were assessed. Results The highest percentage of SDS-I was significant for CC/S and CC/S-W/S-M. Total microbial biomass showed the highest value for sequences that included CC compared to S-S. Generalized Procrustes analysis was utilized to investigate the consensus among crop sequences, primarily distinguishing CC (CC/S and CC/S-W/S-M) from the others. Conclusions Even when crop rotations were observed to affect the microbial biomass nutrient contents, there was an increase in the incidence of SDS for sequences that included the cover crop. Therefore, the progression of this disease needs further analysis concerning the inclusion of cover crops and previous crops.