Research Projects

Nitrogen oxides (NOx) are major air pollutants and can react with volatile organic compounds (VOC) under sunlight to form ozone, a principal ingredient of smog. Smog is harmful to both human health and the environment. Cropland is a known source of NOx, but its contribution to California’s NOx inventory has not been determined. An earlier study indicated that out of the world’s annual 190 million tons of NOx emissions, about one third was produced from soils by microorganisms. In the intensively managed California’s cropping systems, nitrogen (N) fertilizers are regularly applied to the soil to boost crop yields. The increased level of N in the soil could enhance soil-induced NOx. This project will measure soil NOx emissions from a range of California’s cropping systems under various environmental and management conditions. The proposed study is an add-on component to three on-going nitrous oxide (N2O) monitoring efforts. The results of the study are expected to provide an estimate of NOx emissions from California’s agricultural soils and ozone modeling input by including NOx emissions from the soil.