Nitrogen (N) losses negatively impact groundwater quality. Spring wheat genotypes varying in N-fertilizer recovery were studied (by using lysimeters) for their potential to minimize NO3-N leaching during spring and summer, over a three-year period. Additionally, we examined to what extent root growth and NO3-N leaching explain the well-known difference found between apparent and isotopic N reco...

Estimating the additional amount of global photosynthetic arbon influx into terrestrial ecosystems (PG) becomes possible with a leaf-level factor (Y) developed by Luo & Mooney only when an increase in atmospheric CO2 concentration (Ca) is small. Applying the Y factor to study long-term stimulation of PG with a large increase in Ca needs understanding of adjustments in leaf properties, canopy st...

Over the past decade, there has been a rapid increase in dairy farming in New Zealand. Nitrate leaching from intensive agricultural systems, e.g. dairy farms, is suspected to cause increased nitrate concentrations in ground and surface waters. The objective of this research programme was to determine nitrate leaching losses on dairy pasture systems as affected by the application of dairy shed e...

A large reservoir of bioavailable nitrogen (up to approximately 10(4) kilograms of nitrogen per hectare, as nitrate) has been previously overlooked in studies of global nitrogen distribution. The reservoir has been accumulating in subsoil zones of arid regions throughout the Holocene. Consideration of the subsoil reservoir raises estimates of vadose-zone nitrogen inventories by 14 to 71% for wa...

The production of corn or soybeans for bio-based fuels and materials requires significant inputs of nitrogen (FN) and phosphorus fertilizer (FP) to increase grain yields. Approximately 50% of these nutrients are integrated into plant biomass. The remaining 50% is volatilized, leached into surface and groundwater, or transformed into gaseous species such as N2, NO, or N2O. Recent efforts to comp...

The primary mode of nitrogen (N) loss from tile-drained row-cropped land is generally nitrate-nitrogen (NO3-N) leaching. Although cropping, tillage, and N management practices can be altered to reduce the amount of leaching, there are limits as to how much can be done. Data are given to illustrate the potential reductions for individual practices such as rate, method, and timing of N applicatio...

Measurements of nitrate deposition and streamwater chemistry in the Tillingbourne Catchment, in Southern England, made in 1979-1982 and 1999-2001 show a 216% increase in Nitrogen leaching despite a reduction in N inputs. Both the historical and current data sets have been modelled using the Integrated Nitrogen Model in Catchments (INCA). The process-based model is shown to reproduce the histori...

Climate and terrestrial biosphere models consider nitrogen an important factor in limiting plant carbon uptake, while operational environmental models view nitrogen as the leading pollutant causing eutrophication in water bodies. The community Noah land surface model with multiparameterization options (Noah-MP) is unique in that it is the next-generation land surface model for the Weather Resea...

Denitrification and hydrologic leaching are the two major pathways by which nitrogen is lost from the terrestrial biosphere. Humid tropical forests are thought to dominate denitrification from unmanaged lands globally, but there is large uncertainty about the range and key drivers of total N gas emissions across the biome. We combined pantropical measures of small watershed stream chemistry wit...

The objectives of this research were to evaluate nitrate N (NO³-N) leaching and turf response to nitrogen rate (NR) and irrigation regime (IR) in 'Floratam' St. Augustinegrass ( [Walt.] Kuntze.) and 'Empire' zoysiagrass ( Steud). The research was conducted in Citra, FL, from 2005 through 2007. Nitrogen (N) was applied at annual rates of 32, 64, 128, and 196 kg ha⁻¹ in 2005, and at 49, 196, 343,...