EFECTO DEL RIEGO SUPLEMENTARIO SOBRE LAS PROPIEDADES QUÍMICAS Y FÍSICAS EDÁFICAS EN EL SUDOESTE BONAERENSE.

Supplementary irrigation with water of dubious quality can have adverse effects on soil properties. The aim of this study was to assess the impact of supplementary irrigation on soil chemical and physical properties in fields of the Southwestern Buenos Aires province, which generally involve seed production. The surface texture of the soil ranges from sandy loam to loam and clay loamy. The treatments were: Rainfed (corner) and Irrigated (center pivot). Soil samples were collected from 41 field situations at 0-10 cm and 10-20 cm depth, and organic carbon (CO), pH, electrical conductivity (CE), and exchangeable sodium percentage (PSI) were determined. In 12 of the fields, additional measurements were made for infiltration rate, bulk density (0-5 cm and 10-15 cm, Dap), mechanical resistance (0-5 cm and 10-15 cm, RM), and gravimetric moisture content (0-5 cm and 10-15 cm, HG). Data were analyzed using Paired t-tests. Organic carbon content was similar under Rainfed and Irrigated situations at both depths. Soil pH, CE, and PSI at 0-10 cm and 10-20 cm showed a statistically significant increase due to irrigation (p < 0.05), with the order of increase being PSI > CE > pH. The infiltration rate showed no significant differences (p=0.683) between Rainfed and Irrigated, with high variability in situations under irrigation. However, irrigated situations had a 6% higher Dap compared to Rainfed ones (p=0.0005) at 10-15 cm. RM values displayed significant variability. The assessments of soil physical quality conducted in this study did not reveal clear trends or pronounced soil degradation. Nevertheless, it is necessary to continue monitoring the long-term soil quality and implement preventive practices to promote sustainable management of these productive systems. [ABSTRACT FROM AUTHOR]