Agricultural utilization of ecogypsum coming of the reaction of sulfuric acid and calcium carbonate

Abstract

The agricultural gypsum used as a conditioner in the improvement of the chemical conditions of the soils, acting even in the sub-superficial layers of the soil, but without altering its pH. The objective of this work was to evaluate the influence of the use of the agricultural Ecogypsum produced from industrial waste in the pH of the soils of different textures, that received the material in the superficial layer. Twenty-four containers were assembled with PVC pipes, 11 centimeters in diameter and 35 centimeters in length. Two types of soil were conditioned in these tubes and then the Ecogypsum was applied superficially in the ratio of 1.0; 3.0 and 5.0 ton ha.1, in addition to the control treatment, without application. During 30 days the soils were irrigated periodically. After this period, pH analyzes were carried out along the soil profile, every 2.0 centimeters depth, in order to evaluate its Ecogypsum translocation capacity. The superficial application of the Ecogypsum in the soils provided increase of the pH in the superficial and sub-superficial layers. The Ecogypsum increased soil pH in the surface layer where it was applied but showed reduced leaching to the deeper layers of the silt-free soil. In the sandy loam, the Ecogypsum effect was observed even in the deepest layers indicating high percolation and reactivity, probably due to the higher presence of macropores and higher hydraulic conductivity. The lowest tested Ecogypsum dosage (1.0 ton.ha1) was sufficient for change the pH of both soils up to the 6.0-centimeter layer.