C Sotomayor, JP Navarro Di Marco, L Ludueña, A Peña Malavera and GA Sanzano
Estación Experimental Agroindustrial Obispo Colombres, Tucumán, Argentina; csotomayor@eeaoc.org.ar
In vinasse-irrigated soils of the province of Tucumán, previous evaluations have primarily focused on chemical indicators, with limited attention given to microbiological parameters. The objective of this study was to evaluate total enzyme activity (FDA) as a microbiological indicator in a Typic Hapludoll with an argic horizon, irrigated with vinasse for three consecutive years. Additionally, the study aimed to assess its relationship with pH, salinity (EC), exchangeable potassium (K⁺), and soil organic carbon (SOC). A completely randomized block design was used, consisting of eight treatments derived from different vinasse application levels and two soil depths (0–5 cm and 5–15 cm). The vinasse treatments included: V0 (control), V100 (100 m³ ha⁻¹ yr⁻¹), V150 (150 m³ ha⁻¹ yr⁻¹), and V300 (300 m³ ha⁻¹ yr⁻¹). FDA exhibited a significant interaction among the evaluated factors and was notably higher in the vinasse-treated soils compared to the control. Soil pH increased significantly in the V150×0–5 cm and V300×0–5 cm treatments compared to V0×0–5 cm, with similar trends observed at the 5–15 cm depth. Regarding EC, significant differences were found between V150 and V300 at 0–5 cm, while only V300 showed significant increases at 5–15 cm. Exchangeable K⁺ levels increased significantly in the V150×0–5 cm and V300×0–5 cm treatments. At the 5–15 cm depth, all vinasse-treated plots exhibited significantly higher K⁺ levels, with the highest values observed in V300. SOC values were elevated in the 0–5 cm layer across all treatments.