Clay stabilization and recovery of soil functions of a degraded solodic planosol through incorporation of agrominerals: A case study in southern Brazil

Abstract

This paper describes the performance of addition rates of basaltic breccia and agricultural gypsum on clay stabilization and nutrients release of a solodic Planosol from a degraded borrow area located in Southern Brazil. A leaching experiment was carried out in PVC cylinders filled with 1.5 kg of soil (C horizon), in which two chemical amendments were added in three different proportions: a) basaltic breccia in 7, 14 and 21 Mg ha−1 doses; b) agricultural gypsum in 7, 14 and 21 Mg ha−1 doses; and c) a standard soil, without chemical correction. Distilled water (300 mL) were added every 7 days for 20 weeks and the pH, electrical conductivity, calcium, magnesium, sodium and potassium contents and the water-dispersible clay were analyzed in the collected leachates. Gypsum was more efficient than basaltic breccia to promote clay flocculation, even at the lower rate (7 Mg ha−1). The application of basaltic breccia up to 21 Mg ha−1 reduced the amount of nutrients released directly to the soil solution, reducing soil leaching. The application of basaltic breccia at the dosage of 7 Mg ha−1 was able to reduce more than 65% of the water-dispersive clay from the degraded solodic Planosol.