Nitrous oxide emissions from soils planted with rice

effect of a nitrification inhibitor

Abstract

Nitrous oxide (N₂ O) is a greenhouse gas produced both by denitrification and nitrification processes and may constitute a significant nitrogen loss from agricultural soils N₂ O losses in rice cultive in Uruguay have been scarely studied. The aim of this work was to measure the effect of a nitrification inhibitor on the N₂ O emissions from a rice field soil and to evaluate the contribution of nitrification and denitrification. The assay was placed in a greenhouse and consisted in urea and ENTEC (containing nitrate, ammonium and the nitrification inhibitor DMPP) fertilization. A closed-chamber technique was used for collecting gas samples at different dates, which were analysed for N₂ O by gas chromatography. Thirty days after fertilization soil nitrate content and N₂ O emission were lower for ENTEC treatment than for urea, confirming nitrification inhibitor effect. No emission was detected from 10 days after flooding for any treatment. N₂ O originated from nitrification was lower for ENTEC treatment 14 days after sowing. After 35 days N₂ O was due to denitrification in all treatments.