Carbon Dioxide Flux of Conventional and Slow or Controlled Release Nitrogen Fertilizers in Coffee Crop

Abstract

ABSTRACT The use of nitrogen (N) fertilizers is of great agronomic, economic, and environmental importance. The present study was performed to evaluate carbon dioxide (CO2) flux of conventional and slow or controlled release N fertilizers. The experiment was carried out under field conditions in an Oxisol under coffee crop. The treatments were: urea, urea dissolved in water, ammonium nitrate, ammonium sulfate, urea + NBPT, urea + S0 + polymer, urea + plastic resin, urea + 0.15% Cu + 0.4% B and urea formaldehyde distributed in three fertilizations with doses of 150 kg ha−1 of N (450 kg ha−1 year−1). Total CO2 flux was measured on soil surface using an infrared gas analyzer with a dynamic closed chamber constructed from a PVC pipe. Daily CO2 emissions for urea + plastic resin, urea + NBPT, ammonium nitrate and ammonium sulfate were lower than urea in all fertilizations. Total CO2 emissions from fertilizers were ranked as: urea (2819.5 kg ha−1) > urea + S0 + polymer (2265.1 kg ha−1) > urea + Cu + B (2065.9 kg ha−1) = urea formaldehyde (1401.9 kg ha−1) = urea dissolved in water (1586.1 kg ha−1) = urea + plastic resin (1756.8 kg ha−1) = urea + NBPT (1561.2 kg ha−1) = ammonium sulfate (1936.2 kg ha−1) = ammonium nitrate (1465.6 kg ha−1) = control (1629.7 kg ha−1).