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The quality indicators are suitable tools to determine the state of the soil and the effects of different uses and management on it. The aim of the present work was to evaluate the quality of sub-tropical Argiudolls and Hapludolls subjected to different uses in Formosa, using a minimum set of indicators (MSI). Changes in soil use and the application of management techniques to maximize agricultural production are frequent in the world. In Formosa, Argentina, improvements in the productive infrastructure and low market value of the land, promote that these changes occur faster than the monitoring of the ones. The effects of 25 years of continuous agricultural use, extensive livestock in implanted pastures and fruit crops, in relation to the native forest were analyzed. The MSI consisted of five variables: total organic carbon, particulate organic carbon, total nitrogen, structural stability and bulk density. The baseline of the indicators was determined and threshold values were established. The standardized MSI was analyzed graphically. Particulate carbon and structural stability were the most sensitive indicators. Continuous agriculture degraded the edaphic system, resulting in lower values of indicators than the thresholds. It produced a decrease of 74% of the particulate organic carbon and 63% of structural stability, with possible impact on the resilience of the system. Fruit crops led to a decrease in soil quality causing particulate organic carbon and structural stability to approach values that compromise their natural recovery. The implanted pasture improved the quality of the soil with respect to the degraded native forest.

Aims: The objective of the present work was to evaluate the annual evolution of the electrical conductivity and the reaction of the soil, in a Natraqualf of the northwest of the Argentine Pampean Plain, treated with a subsoiler and sowing of wheatgrass. Methodology: Four treatments were established in plots of 400 m2: natural pasture; pasture with wheatgrass (Thynopirum ponticum); natural pasture with subsoiling and wheatgrass pasture with subsoiling. Soil samples were extracted at depths of 0-15 cm, 15-30 cm and 30-45 cm, in January, April, July and October. The edaphic parameters analyzed were: pH, electrical conductivity and bulk density. In October, the dry matter production was determined by treatment. The monthly variation of the depth of the groundwater and its chemical characteristics was measured. Results: The depth of the water table fluctuated between 1.30 m and 0.70 m. The implantation of wheatgrass combined with subsoiling produced a decrease in electrical conductivity from 23.7 dS.m-1 to 3.4 dS.m-1 at 0-15 cm, and from 18.3 dS.m-1 to 7.9 dS.m-1 at 15-30 cm. Soil pH decreased almost one unit in the first 30 cm of depth of the treatments that included wheatgrass. The bulk density was reduced from 1.39 to 1.03 g.cm-3 in the treatment with subsoiling and wheatgrass, and 1.09 g.cm-3 in the wheatgrass treatment without subsoiling. The salt concentration and reaction of the soil at more than 30 cm did not show significant changes in the course of the work. Conclusion: The implantation of wheatgrass, combined with the use of a “mole plow” subsoiler, in the studied soil, produces a significant decrease in the salt content and soil pH in the first 30 cm of depth. At more than 30 cm the salt concentration and reaction of the soil is determined by the groundwater.