In northern Japan, declines in soil nitrogen fertility have occurred in paddy–upland rotation systems with soybean cultivation. A six-year lysimeter experiment was conducted to evaluate the nitrogen budget in paddy–upland rotation (three-year for upland soybean, then three-year for flooded paddy rice) and to clarify the effect of preceding compost application (immature or mature compost over fo...

This paper contrasts the natural and anthropogenic controls on the conversion of unreactive N2 to more reactive forms of nitrogen (Nr). A variety of data sets are used to construct global N budgets for 1860 and the early 1990s and to make projections for the global N budget in 2050. Regional N budgets for Asia, North America, and other major regions for the early 1990s, as well as the marine N ...

This paper contrasts the natural and anthropogenic controls on the conversion of unreactive N2 to more reactive forms of nitrogen (Nr). A variety of data sets are used to construct global N budgets for 1860 and the early 1990s and to make projections for the global N budget in 2050. Regional N budgets for Asia, North America, and other major regions for the early 1990s, as well as the marine N ...

Abstract Emissions of reactive nitrogen (N r ) give rise to a wide range environmental problems. Nitrogen budgets for various systems and on different scales are an established tool quantify the sources fate N . The national budget (NNB) Germany calculates flows eight pools: Atmosphere, Energy Fuels, Material Products in Industry, Humans Settlements, Agriculture, Forest Semi-natural Vegetation,...

Until fairly recently, study of the marine nitrogen cycle was considered to be important but a bit dull. Important because nitrogen had long been recognized as an essential nutrient that often limits primary production in the ocean but dull because the residence time of fixed nitrogen in the ocean was believed to be long (∼10 000 yr; Emery et al., 1955), and its budget, like those of most other...

The ocean's nitrogen cycle is driven by complex microbial transformations, including nitrogen fixation, assimilation, nitrification, anammox and denitrification. Dinitrogen is the most abundant form of nitrogen in sea water but only accessible by nitrogen-fixing microbes. Denitrification and nitrification are both regulated by oxygen concentrations and potentially produce nitrous oxide (N2O), a...

A missing link in the nitrogen cycle has recently been found: bacteria capable of oxidizing ammonium to nitrogen gas (N2). This new source of N2 has now been detected in both the water column and the sediments in marine environments. This discovery is important because it necessitates re-evaluation of (1) major fluxes in the global nitrogen budget and (2) regulation of the processes leading to ...