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GLOBAL BIOGEOCHEMICAL CYCLES, VOL. 17, NO. 4, 1115, doi:10.1029/2003GB002060, 2003

Global modeling of the fate of nitrogen from point and nonpoint sources in soils, groundwater, and surface water

G. Van Drecht

Netherlands Environmental Assessment Agency, National Institute for Public Health and the Environment, Bilthoven, Netherlands


A. F. Bouwman

Netherlands Environmental Assessment Agency, National Institute for Public Health and the Environment, Bilthoven, Netherlands


J. M. Knoop

Netherlands Environmental Assessment Agency, National Institute for Public Health and the Environment, Bilthoven, Netherlands


A. H. W. Beusen

Netherlands Environmental Assessment Agency, National Institute for Public Health and the Environment, Bilthoven, Netherlands


C. R. Meinardi

Netherlands Environmental Assessment Agency, National Institute for Public Health and the Environment, Bilthoven, Netherlands


Abstract

We present a global model that describes the fate of nitrogen (N) from point and nonpoint sources in the hydrological system up to the river mouths at the 0.5° by 0.5° spatial and annual temporal resolution. Estimates for point sources are based on population densities, per capita human N emissions, and data on sanitation coverage and wastewater treatment. For nonpoint sources, we use spatial information on land use, climate, hydrology, geology, and soils, combined with data on N inputs (fertilizers and animal manure, biological N fixation, and atmospheric deposition), and outputs (N removal in harvested agricultural products, ammonia emissions). Denitrification in the root zone and nitrate leaching to groundwater are calculated with a model that combines the effect of temperature, crop type, soil properties, and hydrological conditions. The nitrate concentration of the outflow for shallow and deep groundwater layers is based on historical inputs of fertilizer N and the effects of residence time and denitrification. In-stream N retention is based on a global estimate of 30% of the N discharged to surface water. Calculated and reported total N concentrations of discharge near the river outlet agree fairly well. However, our model systematically overestimates total N concentrations for river basins with mean annual temperature >0°C.

Received 5 March 2003; accepted 3 September 2003; published 13 December 2003.

Index Terms: 1615 Global Change: Biogeochemical processes (4805); 1803 Hydrology: Anthropogenic effects; 1871 Hydrology: Surface water quality; 1831 Hydrology: Groundwater quality.

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Citation: Van Drecht, G., A. F. Bouwman, J. M. Knoop, A. H. W. Beusen, and C. R. Meinardi (2003), Global modeling of the fate of nitrogen from point and nonpoint sources in soils, groundwater, and surface water, Global Biogeochem. Cycles, 17(4), 1115, doi:10.1029/2003GB002060.