Nitrogen and phosphorus losses from agriculture into surface waters; the effects of policies and measures in the Netherlands

Abstract

The increased input of fertilizers and animal wastes after 1950 has boosted agricultural crop production to a high level in many industrialized countries, but it has also contributed to increased nitrogen and phosphorus emissions from agriculture to groundwaters and surface waters. This paper summarizes the pathways and controls of nitrogen and phosphorus losses to surface waters, and it presents estimates and predictions of the losses from agricultural soils in The Netherlands into surface waters, before and after the implementation of policies and measures to reduce nutrient losses from agriculture. Implementation of the nutrient accounting system MINAS, aiming at a step-wise lowering of nitrogen and phosphorus surpluses at farm level, will decrease the total nitrogen and phosphorus surpluses between the years 1985 and 2008 by 58 and 82%, respectively. These large decreases are the result of a strong decrease in the input via fertilizers and animal wastes, combined with only a minor decrease in the output via harvested products. Nitrogen emissions from agricultural land to surface waters will decrease by 38% between 1985 and 2008. Phosphorus emissions from agricultural land to surface waters are expected not to decrease on the short term.

Do Food Processing Industries Contribute to the Eutrophication of Aquatic Systems?

“…A case study in the Netherlands, summarized by Oenema and Roest (1998), serves as an example of the growing interest in the control of di!use sources of both nitrogen and phosphorus. Between 1985 and, in the Netherlands, the total loading of surface waters with nitrogen and phosphorus diminished (as a consequence of point-source control), while the contribution from agriculture remained at the same level and thus proportionally increased.…”

“…However, phosphorus emissions from agricultural land to surface waters are not supposed to decrease during that time period, even though the phosphorus surpluses shall decrease by more than 80%. Indeed, although the rate of loading soils with phosphorus is expected to decrease, it remains positive, preventing any decrease in phosphorus export to surface waters (Oenema and Roest, 1998). Other national initiatives regarding di!use pollution of both nitrogen and phosphorus, such as the de"nition of Best Management Practices (e.g., Ferti-mieux in France), have been taken in the E.U.…”

Identification of nitrogen sources to four small lakes in the agricultural region of Khorezm, Uzbekistan

“…In arid regions, water supplies are often scarce, and the pollution of surface and groundwater from nonpoint sources such as agriculture leads to a diminished supply of quality water available for domestic and recreational uses. Several studies link increased agricultural N use in watersheds or riparian zones to N inputs to lakes (Shannon and Brezonik 1972;Howarth et al 1996;Oenema and Roest 1998;Vander Zanden et al 2005). However, variability in agricultural practices, soil type, and hydrologic condition within a particular watershed or riparian area makes it difficult to generalize the impact of land use on surface waters.…”

Reduced nitrate concentrations in shallow ground water under a non-fertilised grass buffer strip

“…Since the end of the previous century N and P loads to surface water from point sources have decreased considerably (Oenema and Roest 1998) and currently the focus is on non-point sources . In the Netherlands, non-point sources of N and P originate mainly from agricultural inputs (Orleans et al 1994;Oenema and Roest 1998;. To reduce non-point loads of nutrients from agriculture, source oriented and effect oriented measures are taken.…”