Nitrate leaching from a Latosol after application of liquid swine manures in different pH values and organic matter contents

Abstract

Liquid swine manures are produced in large volumes in the western Paraná and Santa Catarina states and are reused as a source of nutrients. This study aimed to evaluate the losses of nitrate (N-NO3-1) after application of liquid swine manures in three samples of a Latosol (Rhodic Eutrudox) with different levels of soil organic matter and pH collected at different depths. The experimental design was completely randomized with one soil, three levels of soil organic matter (34.09, 22.36 and 8.6 g dm-3), four pH in CaCl2 (4.0, 5.0, 6.0 and 7.0) conditions and three replications. Each experimental unit contained 450 cm3 of soil that received a dose of liquid swine manures equivalent to 120,000 dm-3 ha-1. The concentration of N-NO3-1 was evaluated in the leaching solution after the weekly application of water equivalent to 150 mm for a period of 35 days. The amount of N-NO3-1 leached increased with soil organic matter content and soil pH. The amount of nitrate leached tends to be maximum at pH close to or above 7.0.