Annual cycles of N2O production and transfer at the soil-atmosphere interface in a desert site

摘要

N2O concentrations in a desert soil profile were measured weekly to biweekly over 2 annual cycles in Gilgal, Jordan Valley, Israel. The average concentration for the whole period varied between 0.366 ppm (plus or minus 0.086) at the top 2 cm and 0.386 (plus or minus 0.115) at 30 cm depth. Increases in N2O concentration were observed at all depths during the late winter-spring period and resulted in net flux of N2O from the soil to the atmosphere. Increased N2O production in desert soils is attributed to nitrification of NH4 released during decomposition and ammonification of organic residues. If representative of desert ecosystems on the global scale, this seasonal burst in N2O emission may contribute to the increased atmospheric N2O concentration in the northern hemisphere observed in the spring.