Uploaded by: Knoema
Accessed On: 18 March, 2019
The Gross Nutrient Balance provides an insight into the links between the use of agricultural nutrients, their losses to the environment, and the sustainable use of soil nutrients resources. It consists of the Gross Nitrogen Balance and the Gross Phosphorus Balance and is intended to be an indicator of the potential threat of surplus or deficit of two important soil and plant nutrients in agricultural land. It shows the link between agricultural activities and the environmental impact, identifying the factors determining the nutrients surplus or deficit and the trends over time.
Nitrogen (N) and Phosphorus (P) are key elements for plants to grow. A persistent deficit of these nutrients can lead in the long term to soil degradation and erosion. When N and P are however persistently applied in excess, they can cause surface and groundwater (including drinking water) pollution and eutrophication. The Gross Nitrogen Balance also includes Nitrogenous Emissions from livestock production and the application of manure and fertilizers. These nitrogenous emissions include: - Ammonia (NH3) contributing to acidification, eutrophication and atmospheric particulate pollution), and - Nitrous oxide (N2O), a potent greenhouse gas contributing to global warming. The gross nutrient balance is calculated as the balance between inputs and outputs of nutrients to the agricultural soil. A balance per hectare is also presented. The Inputs are:
- Consumption of Fertilizers,
- Gross Input of Manure, and
- Other Inputs. The Outputs are:
- Removal of nutrients with the harvest of Crops,
- Removal of nutrients through the harvest and grazing of Fodder, and
- Crop Residues removed from the field.
The data presented in the table are calculated from basic data from various data sources multiplied with coefficients to derive the nutrient content. The basic data used include the consumption of inorganic and other organic fertilizers (excluding manure) (tonnes), livestock population (1000 heads), manure imports, withdrawals and stock changes (tonnes), crop and fodder production (tonnes), crop residues removed from the field (tonnes), use of seeds and planting materials planted in the soil (tonnes), area of leguminous crops (1000 ha), area of arable land, land under permanent crops and permanent grassland (1000 ha). Countries may have used different types of data sources for these data. For instance some countries use estimates of the livestock population based on data from the Livestock Surveys or they have used other data sources like national registers on livestock. Data sources that are used and are available in Eurostat include: Crop Production Statistics (production and landuse), Livestock Statistics (livestock numbers), Farm Structure Survey (livestock numbers). Countries have estimated coefficients based on measurements, scientific research, expert judgment, default values etc.