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Global annual NO emissions from soil are of the order of 10 Tg NO-N. This is about half the amount fossil fuel combustion processes contribute to the annual global NOx budget. Reducing the emissions of soil derived NOx requires an understanding of the source of the flux and the processes that determine its magnitude. A thorough investigation of possible(More)
The aim was to investigate the effects of different N fertilisers on nitrous oxide (N2O) flux from agricultural grassland, with a view to suggesting fertiliser practices least likely to cause substantial N2O emissions, and to assess the influence of soil and environmental factors on the emissions. Replicate plots on a clay loam grassland were fertilised(More)
This review examines the interactions between soil physical factors and the biological processes responsible for the production and consumption in soils of greenhouse gases. The release of CO 2 by aerobic respiration is a non-linear function of temperature over a wide range of soil water contents, but becomes a function of water content as a soil dries out.(More)
The aims of this study were to assess the effectiveness of the nitrification inhibitors dicyandiamide (DCD) and nitrapyrin on reducing emissions of nitrous oxide (N2O) following application of NH4 + or NH4 +-forming fertilisers to grassland and spring barley. DCD was applied to grassland with N fertiliser applications in April and August in 1992 and 1993,(More)
The potentially mineralisable nitrogen extracted from 10 soils by two methods involving boiling with dilute KCl were compared with the actual uptake of soil N by spring barley in the field, as determined with the use of 15N-labelled fertiliser. Generally good correlations were found for those soils which had previously been cropped with cereals (defined in(More)
Field trials were carried out to study the fate of15N-labelled urea applied to summer maize and winter wheat in loess soils in Shaanxi Province, north-west China. In the maize experiment, nitrogen was applied at rates of 0 or 210 kg N ha−1, either as a surface application, mixed uniformly with the top 0.15 m of soil, or placed in holes 0.1 m deep adjacent(More)
Nitrous oxide (N2O) flux simulations by four models were compared with year-round field measurements from five temperate agricultural sites in three countries. The field sites included an unfertilized, semi-arid rangeland with low N2O fluxes in eastern Colorado, USA; two fertilizer treatments (urea and nitrate) on a fertilized grass ley cut for silage in(More)
OBJECTIVES To determine the incidence, clinical manifestations and risk factors for immune reconstitution inflammatory syndrome (IRIS) in young children initiating highly active antiretroviral therapy (HAART). DESIGN A prospective cohort of antiretroviral-naïve HIV-infected children less than 24 months of age enrolled in a treatment strategies trial in(More)
The present work aims at evaluating the effect of cycloheximide at concentrations of between 0.5 and 5mgg–1 on N2O and NO3 – production in two slightly alkaline soils, sampled from deciduous woodland and arable cultivation. In the first experiment, peptone was used as the “inducing substrate” for heterotrophic activity, and soil was incubated with(More)
Transungual transport is hindered by the inherent small effective pore size of the nail even when it is fully hydrated. The objectives of this study were to determine the effects of chemical enhancers thioglycolic acid (TGA), glycolic acid (GA), and urea (UR) on transungual transport and iontophoresis efficiency. In vitro passive and iontophoretic transport(More)