author(s)
Sabattini Julián Alberto, Befani Romina, Hernández Juan Pablo, Boschetti Graciela, Cian Juan Carlos, Sabattini Ivan, Díaz Eduardo and Sabattini Rafael Alberto

abstract
The aim of the present investigation was to determine the spatial modification of the chemical and physical characteristics of an Alfisol Soil affected by Atta vollenweideri nests in a semixerophite native forest of the Espinal Ecorregion. The study was conducted in north of the province of Entre Ríos (Argentina) in July 2015, selecting 10 nests. In each nest composite samples of surface soil were taken in five positions. The textural components of soil and nine chemical variables were evaluated and used parametric and non-parametric analysis of variance techniques. The OC content increased significantly as the distance to the nest increased, from 3.20 mg C kg^-1 in the crest of the nest, to 15.04 mg C kg^-1 at 60 m. There was a significant increase in pH, CEC, Na, EC and PENa in the crest of the nests with respect to the base, at 15, 30 and 60 m from the nest. The soil on the ridge of the nest showed a slight salinity (3.61 ± 1.55 dS.m^-1) and slight sodicity (12.42 ± 3.65%) with respect to the adjacent soil. Nests of A. vollenweideri in Alfisols soils, negatively alters the chemical and physical properties of the soil in the first 15 meters from the base of the nest.