Nutrient Balance for Nitrogen

Nutrient Balance for NitrogenA nitrogen balance calculates the balance between nitrogen added to an agricultural system and nitrogen removed from the system. It is important to maintain an equilibrated nitrogen balance, because a persistent deficit of nitrogen in agricultural soil can cause decreasing soil fertility, whereas a high surplus of nitrogen implies a risk of pollution of surface water, groundwater and air. For this reason the nitrogen balance is an important agri-environmental indicator that can be used to analyse the interactions between agriculture and the environment and to evaluate the impact of agricultural policy on the environment.
In this project we calculated a gross nitrogen balance that takes into account organic and mineral fertilizer use, atmospheric nitrogen deposition, biological nitrogen fixation, the use of seeds and planting material, crop removal and ammonia emission to calculate the soil surplus.

However other approaches of N balance are possible. Regional administrations in Belgium use nitrogen balances for controlling the N added to agricultural soil by farmers or for policy-making. Depending on the objective, these approaches differ mainly in the nitrogen input and output factors that are taken into account.
The previous work done by the Institute for Agricultural and Fisheries Research (ILVO) on nutrient balance for Flanders (Lauwers et al., 2004 and Vervaet et al., 2006) was an excellent starting point for this project. The operational model of ILVO provides transparent calculation modules for nitrogen inputs and outputs to calculate a gross nitrogen balance for Flanders.

The main objectives of this project are:

  • to adapt the Flemish model and coefficients to the Walloon Region
  • bring up to date OECD tables: data and balance calculations (extend it up to 2005) at regional and national level
  • to calculate a nitrogen balance at NUTS 3 (districts) for the most recent year for which all information is available and visualize results in a map

It was not possible to calculate directly a nutrient balance for Belgium as a whole, as the agricultural situation and the legislation are different in Flanders and the Walloon Region and data are gathered in a different way at different institutes. Therefore we calculated the nutrient balances of Flanders, the Walloon Region and Brussels Capital-Region separately and the nitrogen balance of Belgium was calculated as the sum of the regions.

The results for the Flemish Region and the used methods were provided by ILVO. As some calculation methods and coefficients were improved since the last report in 2006, for each component a short overview of the used methods and improvements as well as the results from 1990 until 2006 are presented in this report.

Furthermore, we tried to adapt these calculation methods to the Walloon Region and Brussels Capital-Region and to search for all necessary coefficients and data.

As nitrogen surpluses can be highly variable within different regions of a country, another aim of this project was to calculate nitrogen balances at NUTS 3 level or “districts” (Belgian “arrondissements” in French and “arrondissementen” in Dutch). In tables and maps we used reference codes for the districts. In annexe 1.1 the Flemish and Walloon districts are listed with their reference code and their location is shown. The territory of Brussels Capital-Region is at the same time considered as a region and as a district in Belgium. Therefore we did not make the distinction between NUTS 1 and NUTS 3 in Brussels Capital-Region.

In the following chapters we will discuss the calculation methods, used data sources and results of the N input and output factors for Flanders at NUTS 1 and NUTS 3, for the Walloon Region at NUTS 1 and NUTS 3 and for Brussels Capital-Region (NUTS 1 = NUTS 3). The first and the second chapter will discuss respectively livestock activities and land use activities that are main driving factors that will be used for calculation of the N input and output factors. The next chapters will treat the N input and output factors livestock nutrient production, inorganic fertilizer use, N exportation through crop removal, seed inputs, biological N fixation, atmospheric N deposition, the use of other fertilizers, manure import, export and processing and ammonia emission. Next we will discuss the resulting soil N surplus in Belgium at NUTS 1 and NUTS 3. In the last chapter we will present some general conclusions. The detailed results are presented in annexe.

Date d'édition :15/07/2009
Publication du gouvernement :Oui
Type de Bibliothèque Digitale: , Environnement , Statistique
Type d'édition:Working Paper