GLOBAL ANALYSIS OF THE POTENTIAL FOR N2O PRODUCTION IN NATURAL SOILS

A simple global model of the production potential of nitrous oxide (N2O) in natural soils is developed to analyze the relative importance, both geographically and seasonally, of the different controls on N2O production at the global scale. Five major controls on N2O production are included: (1) input of organic matter, (2) soil fertility, (3) soil moisture status, (4) temperature, and (5) soil oxygen status. Indices for the controls are derived form global gridded (1-degrees x 1-degrees resolution) data bases of soil type, soil texture, NDVI and climate. The model explains close to 60% of the variability found in measurements reported at about 30 sites in six different ecosystems throughout the world. Although this result is reasonable for global analyses, the correlation is considered insufficient to make global estimates of nitrous oxide emission with confidence. The model confirms conclusions from earlier studies that the major source regions of nitrous oxide are in the tropics.