Boreal forests comprise 73% of the world's coniferous forests. Based on forest floor measurements, they have been considered a significant natural sink of methane (CH4) and a natural source of nitrous oxide (N2O), both of which are important greenhouse gases. However, the role of trees, especially conifers, in ecosystem N2O and CH4 exchange is only poorly understood. We show for the first time ...

There has been recent concern about the impact of increased nutrient loading on the northern Everglades ecosystem. We investigated the spatial and temporal distribution of denitrifying enzyme activity (DEA) along a P-enrichment gradient in the Water Conservation Area 2A (WCA-2A) and determined the effects of added P and NO., on DEA. The DEA in soil and detritus layers was measured under anaerob...

There is a lack of understanding of how associations among soil properties and management-induced changes control the variability of greenhouse gas (GHG) emissions from soil. We performed a laboratory investigation to quantify relationships between GHG emissions and soil indicators in an irrigated agricultural field under standard tillage (ST) and a field recently converted (2 yr) to no-tillage...

Cork oak woodlands (montado) are agroforestry systems distributed all over the Mediterranean basin with a very important social, economic and ecological value. A generalized cork oak decline has been occurring in the last decades jeopardizing its future sustainability. It is unknown how loss of tree cover affects microbial processes that are consuming greenhouse gases in the montado ecosystem. ...

Long-term field observations showed that N2O fluxes observed shortly after N application were not significantly affected by elevated CO2 in the Giessen Free Air Carbon dioxide Enrichment (FACE) study. To further investigate this unexpected result a 15N tracer study was carried out under controlled conditions where in parallel treatments either the NH+4 pool ( NH4NO3) or the NO − 3 pool (NH 15 4...

Climate change is causing the intensification of both rainfall and droughts in temperate climatic zones, which will affect soil drying and rewetting cycles and associated processes such as soil greenhouse gas (GHG) fluxes. We investigated the effect of soil rewetting following a prolonged natural drought on soil emissions of nitrous oxide (N2O) and carbon dioxide (CO2) in an agricultural field ...

The aim of this work is to investigate the influence of NO/SO2 on the emissions of N2O from diesel engine. A direct-injection diesel engine (model NF-19SK YANMAR) one cylinder was employed to test the emission. This engine works on fourstroke cycle and was operated at 2200 rpm by 25, 50, and 75% engine load. The experiment by three level sulfur content of fuel by adding DBDS into MDO and experi...

Most studies on soil N2O emissions have focused either on the quantifying of agricultural N2O fluxes or on the effect of environmental factors on N2O emissions. However, very limited information is available on how land-use will affect N2O production, and nitrifiers involved in N2O emissions in agricultural soil ecosystems. Therefore, this study aimed at evaluating the relative importance of ni...

High variability due to soil heterogeneity and climatic conditions challenge measurement of greenhouse gas (GHG) emissions as influenced by management practices in the field. To reduce this variability, we examined the effect of management practices on CO2, N2O, and CH4 fluxes and soil temperature and water content from July to November, 2011 in a greenhouse. Treatments were incomplete combinat...

Benthic chambers were used to measure in situ fluxes of dissolved gases (N2, O2, and N2O) and inorganic nutrients (NO3 , NH4 , and PO4 3 ) in continental shelf sediments of the Mid-Atlantic Bight during spring through autumn (May– November). Denitrification was determined by the rate of increase in N2 relative to Ar, measured using membrane-inlet mass spectrometry. Although sediments were a sou...