A large part of agricultural soils in Europe are exposed to high N inputs because of animal manure and chemical fertiliser use. Large parts of the European natural soils are exposed to high atmospheric N deposition.

High N inputs threaten soil quality, which may negatively affect food and biomass production and biodiversity and enhance emissions of harmful N compounds from soils to water and the atmosphere.

An overview of the major soil functions and soil threats are presented, including a description of the objectives of the European Soil Strategy.

The major N threats on soil quality for both agricultural and natural soils are related to changes in soil organic content and quality, soil acidification, and loss of soil diversity. These threats are described using literature.

Generally, N has a positive effect on soil quality of agricultural soils, because it enhances soil fertility and conditions for crop growth. However, it generally has a negative effect on soil quality of natural soils, because it results in changes in plant diversity.

Soil acts as a filter and buffer for N, and protects water and atmosphere against N pollution. However, the filter and buffer capacity of soils is frequently exceeded by excess of N in both agricultural and natural soils, which results in emission of N to the environment.

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