Guido Fernando Botta

Effects of supplementary irrigation on chemical and physical soil properties in the rolling pampa region of Argentina

AbstractR. Mon, C. Irurtia , G. F. Botta , O. Pozzolo , F. Bellora Melcon , D. Rivero , and M. Bomben. 2007. Effects of supplementary irrigation on chemical and physical soil properties in the rolling pampa region of Argentina. Cien. Inv. Agr. 34(3):187-194 . The effects of supplementary irrigation on soil chemical and physical properties were studied in 21 locations in the north of the rolling pampa region of Argentina. The chemical and physical variables were measured in top soil (0-100 mm) to compare irrigated and non-irrigated soils. Chemical variables were: electrical conductivity (EC), pH, exchangeable sodium percentage (ESP), and organic mater content. Physical variables included structural index (SI) and percolation index (PI) measured in the laboratory, as well as infi ltration, runoff, and soil losses, measured in the fi eld with a small portable rainfall simulator. Water qualit y was established according to its chemical com position and Riverside USA classi fi cation. In irri gated soils, chemical data shows, on average, a slight increase in ESP (from 2.56 to 5.52) and in pH (from 6.13 to 6.45). EC, SI, and PI show the same values in irri gated and non-irri gated soils. The a pplication of a simulated rainfall of 30 mm in 30 min revealed a different soil behavior. Irri gated soils present lower values of water entry and infi ltration rates, and higher values of runoff and soil losses. The variation in chemical and physical soil properties show that within 10 years of supplementary irrigation a slight process of sodication and alkalinization occurs. Water quality and soil chemical data suggest that the sodication process and the increased soil erosion risk must be controlled in order to achieve a sustainable high production system.