INORGANIC PHOSPHORUS FORMS IN AN OXISOL UNDER NO-TILL AFTER INDUSTRIAL AND MUNICIPAL RESIDUES APPLICATION

Abstract

Industrial and municipal residues applied to agricultural crops under no-till (NT) can promote benefits to many soil properties. The reuse of such materials reduces the supply of mineral fertilizers and provides greater economic and environmental sustainability. Besides being attenuators of soil acidity, some of these residues are excellent sources of plant nutrients such as phosphorus (P). Understanding the dynamics of P arising from residues applied in tropical soils is important to assist in crops fertilization management. In this context, the objective was to quantify the inorganic P forms (Pi) through the P fractionation in an Oxisol that received application of municipal and industrial residues. Four residues composed treatments: LC - centrifuged sewage sludge with addition of lime (CaO); LB - sewage sludge from the biodigester with the addition of polyelectrolytes; E - steel slag; and Lcal - lime mud applied at doses of 0, 2, 4 and 8 Mg ha-1. The P fractionation was performed in soil samples collected at 0-5, 5-10, 10-20 and 20-40 cm layers. The LC treatment provided the highest values of anion exchange resin (AER) Pi. The residual P has presented stability thus does not show significant differences regarding its distribution along with the soil profile.