Effects of gypsum, limestone and organic fertilizers on the properties of a Vertisol and sugarcane yield

The accelerated degradation of soils demands urgent study of recovery alternatives for their properties with sustainability criteria. This study was carried out to evaluate the effect of amendment agents on vertisol and their relationship with sugarcane yield. Organic fertilizer (sugarcane filter cake-SFC), natural minerals (gypsum-limestone) and chemical fertilization (nitrogen-phosphorus-potassium-NPK) were applied as treatments. The experiment was carried out in a complete randomized block design with ten treatments and four replicates. The following physical and chemical properties were evaluated: pH in water, pH in KCl, and organic matter, assimilable P2O5 and K2O, degree of soil aggregation, water-stable aggregates, permeability and plastic limit. The sugarcane yield components such as cane yield-CY (t ha-1) and sucrose yield-SY (t ha-1) were evaluated. Amendments of organo-mineral fertilizers with a chemical composition rich in calcium cause, in an acidic vertisol, produce significant increases in the pH, organic matter and assimilable phosphorus, as well as in the structure and their stability. The study of the relationships between physical and chemical properties and sugarcane yield showed high values of R2 (51 - 72%) and a coefficient of determination of 0.68-0.94, which shows a high degree of significance and the extent to which the indicators of the properties studied increase the yields (CY 104-141t ha-1, SY 18-25 t ha-1).