Nitrosation of Soil Organic Matter: III. Nature of Gases Produced by Reaction of Nitrite with Lignins, Humic Substances, and Phenolic Constituents Under Neutral and Slightly Acidic Conditions

Abstract

Abstract Molecular nitrogen, nitrous oxide (N 2 O), nitric oxide (NO), and CO 2 were identified in the gases formed by reacting NO 2 ‐ with soils, humic and fulvic acids, lignins, lignin‐building units, and polyphenols in aqueous buffer solutions of pH 6 and 7 in the absence of oxygen. The composition of the mixture of gases was dependent upon the nature of the material examined, with relatively larger amounts of N 2 being produced from the humic and fulvic acids. Compounds containing methoxyl groups failed to yield detectable amounts of methyl nitrite (CH 3 ONO) at the pH levels found in most soils. The reaction of NO with humic substances in the absence of oxygen led to the production of N 2 O and CO 2 .