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Soils are a dominant source of nitrous oxide (N2O), a potent greenhouse gas. The complexity of drivers of N2O production and emissions has hindered our ability to predict the magnitude and spatial dynamics of N2O fluxes. Soil moisture can be considered a key driver because it influences oxygen supply, which feeds back on N2O sources (nitrification versus denitrification) and sinks (reduction to dinitrogen). Soil volumetric water content is directly linked to dissolved oxygen and to redox potential, which regulate microbial metabolism and chemical transformations in the environment. The relationship between soil moisture and N2O is usually based on incubations of soil at different soil moisture levels. Few studies have focused on the interaction between soil moisture and nitrogen dynamics in the vadose zone. In this thesis soil column and chamber experiments were performed in order to investigate the relationship of soil moisture dynamics to redox sensitive nitrogen dynamics in the organic matter layer of a pasture peatland in Sacramento, Bay Delta area, California. Field data has been analyzed and statistics has been used to evaluate the influence of irrigation practices on spatial pattern of measurements. Data indicate that organic peatland might be an important source of nitrous oxide emissions. The comparison of rainfall, saturation and deposition shown that trace gases emissions, dissolved nitrate and ammonium changed considerably along the soil column profile as a response of the microbial community to the high variability in redox, soil moisture, oxygen experienced by the soil at different depth. Water movement favored the formation of zones at different redox condition, redistributed the nutrient along the soil profile, and considerably changed mineralization,nitrification and dissimilatory reduction to nitrate (DNRA) rates. It was observed an asymmetrical behavior between nitrogen and ammonium profiles. Experiments shown that this assimetry is a function of

Soils are a dominant source of nitrous oxide (N2O), a potent greenhouse gas. The complexity of drivers of N2O production and emissions has hindered our ability to predict the magnitude and spatial dynamics of N2O fluxes. Soil moisture can be considered a key driver because it influences oxygen supply, which feeds back on N2O sources (nitrification versus denitrification) and sinks (reduction to dinitrogen). Soil volumetric water content is directly linked to dissolved oxygen and to redox potential, which regulate microbial metabolism and chemical transformations in the environment. The relationship between soil moisture and N2O is usually based on incubations of soil at different soil moisture levels. Few studies have focused on the interaction between soil moisture and nitrogen dynamics in the vadose zone. In this thesis soil column and chamber experiments were performed in order to investigate the relationship of soil moisture dynamics to redox sensitive nitrogen dynamics in the organic matter layer of a pasture peatland in Sacramento, Bay Delta area, California. Field data has been analyzed and statistics has been used to evaluate the influence of irrigation practices on spatial pattern of measurements. Data indicate that organic peatland might be an important source of nitrous oxide emissions. The comparison of rainfall, saturation and deposition shown that trace gases emissions, dissolved nitrate and ammonium changed considerably along the soil column profile as a response of the microbial community to the high variability in redox, soil moisture, oxygen experienced by the soil at different depth. Water movement favored the formation of zones at different redox condition, redistributed the nutrient along the soil profile, and considerably changed mineralization,nitrification and dissimilatory reduction to nitrate (DNRA) rates. It was observed an asymmetrical behavior between nitrogen and ammonium profiles. Experiments shown that this assimetry is a function of

Soils are a dominant source of nitrous oxide (N2O), a potent greenhouse gas. The complexity of drivers of N2O production and emissions has hindered our ability to predict the magnitude and spatial dynamics of N2O fluxes. Soil moisture can be considered a key driver because it influences oxygen supply, which feeds back on N2O sources (nitrification versus denitrification) and sinks (reduction to dinitrogen). Soil volumetric water content is directly linked to dissolved oxygen and to redox potential, which regulate microbial metabolism and chemical transformations in the environment. The relationship between soil moisture and N2O is usually based on incubations of soil at different soil moisture levels. Few studies have focused on the interaction between soil moisture and nitrogen dynamics in the vadose zone. In this thesis soil column and chamber experiments were performed in order to investigate the relationship of soil moisture dynamics to redox sensitive nitrogen dynamics in the organic matter layer of a pasture peatland in Sacramento, Bay Delta area, California. Field data has been analyzed and statistics has been used to evaluate the influence of irrigation practices on spatial pattern of measurements. Data indicate that organic peatland might be an important source of nitrous oxide emissions. The comparison of rainfall, saturation and deposition shown that trace gases emissions, dissolved nitrate and ammonium changed considerably along the soil column profile as a response of the microbial community to the high variability in redox, soil moisture, oxygen experienced by the soil at different depth. Water movement favored the formation of zones at different redox condition, redistributed the nutrient along the soil profile, and considerably changed mineralization,nitrification and dissimilatory reduction to nitrate (DNRA) rates. It was observed an asymmetrical behavior between nitrogen and ammonium profiles. Experiments shown that this assimetry is a function of

Soils are a dominant source of nitrous oxide (N2O), a potent greenhouse gas. The complexity of drivers of N2O production and emissions has hindered our ability to predict the magnitude and spatial dynamics of N2O fluxes. Soil moisture can be considered a key driver because it influences oxygen supply, which feeds back on N2O sources (nitrification versus denitrification) and sinks (reduction to dinitrogen). Soil volumetric water content is directly linked to dissolved oxygen and to redox potential, which regulate microbial metabolism and chemical transformations in the environment. The relationship between soil moisture and N2O is usually based on incubations of soil at different soil moisture levels. Few studies have focused on the interaction between soil moisture and nitrogen dynamics in the vadose zone. In this thesis soil column and chamber experiments were performed in order to investigate the relationship of soil moisture dynamics to redox sensitive nitrogen dynamics in the organic matter layer of a pasture peatland in Sacramento, Bay Delta area, California. Field data has been analyzed and statistics has been used to evaluate the influence of irrigation practices on spatial pattern of measurements. Data indicate that organic peatland might be an important source of nitrous oxide emissions. The comparison of rainfall, saturation and deposition shown that trace gases emissions, dissolved nitrate and ammonium changed considerably along the soil column profile as a response of the microbial community to the high variability in redox, soil moisture, oxygen experienced by the soil at different depth. Water movement favored the formation of zones at different redox condition, redistributed the nutrient along the soil profile, and considerably changed mineralization,nitrification and dissimilatory reduction to nitrate (DNRA) rates. It was observed an asymmetrical behavior between nitrogen and ammonium profiles. Experiments shown that this assimetry is a function of

Soils are a dominant source of nitrous oxide (N2O), a potent greenhouse gas. The complexity of drivers of N2O production and emissions has hindered our ability to predict the magnitude and spatial dynamics of N2O fluxes. Soil moisture can be considered a key driver because it influences oxygen supply, which feeds back on N2O sources (nitrification versus denitrification) and sinks (reduction to dinitrogen). Soil volumetric water content is directly linked to dissolved oxygen and to redox potential, which regulate microbial metabolism and chemical transformations in the environment. The relationship between soil moisture and N2O is usually based on incubations of soil at different soil moisture levels. Few studies have focused on the interaction between soil moisture and nitrogen dynamics in the vadose zone. In this thesis soil column and chamber experiments were performed in order to investigate the relationship of soil moisture dynamics to redox sensitive nitrogen dynamics in the organic matter layer of a pasture peatland in Sacramento, Bay Delta area, California. Field data has been analyzed and statistics has been used to evaluate the influence of irrigation practices on spatial pattern of measurements. Data indicate that organic peatland might be an important source of nitrous oxide emissions. The comparison of rainfall, saturation and deposition shown that trace gases emissions, dissolved nitrate and ammonium changed considerably along the soil column profile as a response of the microbial community to the high variability in redox, soil moisture, oxygen experienced by the soil at different depth. Water movement favored the formation of zones at different redox condition, redistributed the nutrient along the soil profile, and considerably changed mineralization,nitrification and dissimilatory reduction to nitrate (DNRA) rates. It was observed an asymmetrical behavior between nitrogen and ammonium profiles. Experiments shown that this assimetry is a function of

Soils are a dominant source of nitrous oxide (N2O), a potent greenhouse gas. The complexity of drivers of N2O production and emissions has hindered our ability to predict the magnitude and spatial dynamics of N2O fluxes. Soil moisture can be considered a key driver because it influences oxygen supply, which feeds back on N2O sources (nitrification versus denitrification) and sinks (reduction to dinitrogen). Soil volumetric water content is directly linked to dissolved oxygen and to redox potential, which regulate microbial metabolism and chemical transformations in the environment. The relationship between soil moisture and N2O is usually based on incubations of soil at different soil moisture levels. Few studies have focused on the interaction between soil moisture and nitrogen dynamics in the vadose zone. In this thesis soil column and chamber experiments were performed in order to investigate the relationship of soil moisture dynamics to redox sensitive nitrogen dynamics in the organic matter layer of a pasture peatland in Sacramento, Bay Delta area, California. Field data has been analyzed and statistics has been used to evaluate the influence of irrigation practices on spatial pattern of measurements. Data indicate that organic peatland might be an important source of nitrous oxide emissions. The comparison of rainfall, saturation and deposition shown that trace gases emissions, dissolved nitrate and ammonium changed considerably along the soil column profile as a response of the microbial community to the high variability in redox, soil moisture, oxygen experienced by the soil at different depth. Water movement favored the formation of zones at different redox condition, redistributed the nutrient along the soil profile, and considerably changed mineralization,nitrification and dissimilatory reduction to nitrate (DNRA) rates. It was observed an asymmetrical behavior between nitrogen and ammonium profiles. Experiments shown that this assimetry is a function of