Nitric oxide production in agricultural soils



Numerous papers on nitric oxide have been published covering various aspects ranging from its solution and gas-phase chemistry, biochemical and physiological functions and atmospheric processes. This review emphasizes recent developments in the literature relating to NO/NOx production in agricultural soils. We have tried to minimize overlap with other recent and relevant review articles. Emission measurements that have been made since 1992 are tabulated and discussed in terms of variability, fertilization effects, and advances made in monitoring fluxes. We describe attempts made by a number of authors to utilize ecological markers such as aeration, water, ammonium, nitrate content, etc. in order to distinguish between nitrification and denitrification as the primary source of production and/or consumption in natural field situations. This may allow a rational accounting for the high spatial and temporal variability observed, and the formulation of reliable predictive models. Factors such as diffusion, oxygen, water, and carbon (content and quality) that regulate or significantly influence production, consumption and emission are discussed. Finally some important implications of recent research relating to nitrification and denitrification is presented showing the chemical oxidation of NO which could occur when the acetylene inhibition technique is used.