The indicator presents the nitrogen balance in Slovenia for the period 1992-2008. The data on input and output of nitrogen from agricultural land, and the structure of input and output of nitrogen according to each source are presented, and a comparison with the EU-15 countries for 2000 is given.
The balance of nitrogen (N) in agriculture, according to OECD (2007) methodology, is defined as the difference between input and output of nitrogen from agricultural land. Sources of input of nitrogen in agricultural land represent mineral fertilizers, livestock manure, and other kinds of organic manures, biological nitrogen fixation, atmospheric deposition and nitrogen from the seeds and planting material. Output of nitrogen from agricultural land present harvested agricultural crops.
Image KM22-1: The structure of input of nitrogen on agricultural land in Slovenia in the period 1992-2008
Source: Agricultural Institute of Slovenia, 2010
Image KM22-2: The structure of output of nitrogen from agricultural land in Slovenia in the period 1992-2008
Source: Agricultural Institute of Slovenia, 2010
Image KM22-3: The nitrogen balance in Slovenia in the period 1992-2008
Source: Agricultural Institute of Slovenia, 2010.
Image KM22-4: The nitrogen balance in the old Member States of the European Union (EU-15) and in Slovenia in 2000
Source: Agricultural Institute of Slovenia, 2010; OECD, 2010.
- balanced consumption of nitrogen from mineral fertilizers and livestock manures, gradual increase in the scope of ecological production, and prevention of soil loading from point sources and non-point sources.
- fertilise plants in a way to make the best use of nutrients without being wasted into the groundwater and the atmosphere
- reduction and prevention of further pollution of waters by nitrates from agricultural production.
The balance of nitrogen (N) in agriculture is the difference between the input and the output of nitrogen from agricultural land. Surplus of nitrogen input over output present an environmental threat, because they accumulate on the ground, leach to waters, or end up in the air in gaseous state.
In the period 1992-2008, overall input of nitrogen on agricultural land reduced from 84,266 tons of N to 69,822 tons of N or by 17.1 %. Additionally, the input of nitrogen per hectare of utilised agricultural area has reduced, namely from 152 kg N/ha to 142 kg N/ha or for 6.5 %. The main source of nitrogen input on agricultural land is the nitrogen from mineral fertilizers and livestock manures, which on average contributed 84 % to overall input of nitrogen in the mentioned period (or 42 % for mineral fertilizers as well as for livestock manures). Contributions from other sources of input of nitrogen on agricultural land are lower: atmospheric deposition of nitrogen contributes 10 % to overall input of nitrogen, biological fixation by nitrogen with legume crops 5 %, and input of nitrogen through seeds and planting material 0.4 %.
The main reason for reduced input of nitrogen in the period 1992-2008 is primarily the 35.7 % reduction of nitrogen input from mineral fertilizers. The input of nitrogen from livestock manures has mainly remained unchanged. Due to the reduction utilised agricultural area, also the input of atmospheric nitrogen has reduced (for 11.4 %) and the input of nitrogen through seeds and planting material (for 8.7 %). In the period 1992-2008, due to greater crops and areas of legume crops, only the input of nitrogen by biological fixation increased, namely for 11.6 %.
Output of nitrogen with crops varied considerably in the period 1992-2008, since it amounted between 32,000 and 62,000 tons of N. Output of nitrogen per hectare of utilised agricultural area in the mentioned period amounted between 58 and 122 kg N/ha a year. Such great differences are conditional upon different weather conditions, since mainly in the periods of draught due to lower crop yields, the output of nitrogen also decreases. The main source of nitrogen output in the period 1992-2008 was permanent grassland (around 63 %), arable crops and sown grassland contributed around 35 %, while the contribution of permanent plantations (orchards, vineyards, and olive plantations), and vegetable crops was relatively small (around 2 %).
The balance of nitrogen, thus the difference between the input and the output of nitrogen, indicates a balance surplus of nitrogen. In the period 1992-2008, it amounted between 23 and 94 kg N/ha. We observed the greatest balance surplus (more than 80 kg N/ha) in the years 1992, 1993 and 2003. Until 2000, with the exception of years 1992 and 1993, the balance surplus was 38-66 kg N/ha, and after 2004, it is mainly decreasing, so that in 2008, it was only 24 kg N/ha.
In 2000, Slovenia had a slightly higher balance surplus (66 kg N/ha) than EU-15 average (55 kg N/ha). Among the countries with distinctly higher balance surplus are the Netherlands (226 kg N/ha), Belgium (174 kg N/ha), Luxembourg (117 kg N/ha), and Germany (105 kg N/ha). The lowest balance surplus in 2000, was in France (25 kg N/ha), Italy (37 kg N/ha), and Sweden (38 kg N/ha).
Data for Slovenia:
Objectives summarized by: Resolution on National Environmental Action Plan 2005-2012 (ReNEAP, OG RS, No. 2/06), Rules concerning good agricultural practice in manuring (OGRS, No. 130/04) and Decree concerning the protection of waters against pollution caused by nitrates from agricultural sources (OG RS, No. 113/09).
Data for other countries:Source database or source: Data on the balance of nitrogen for old Member States of the European Union (EU-15) for 2000 are summarized from the website OECD and are available in the framework of the indicator IRENA 18.1 – Gross nitrogen balance (IRENA Indicator Fact Sheet) on the European Environmental Agency website.
Data administrator: OECD.
Data acquisition date for this indicator: November 2009
Methodology and frequency of data collection for the indicator: Data on the balance of nitrogen for old Member States of the EU (EU-15) for 1990 and 2000 are stated on the OECD website. For the indicator we used the data for 2000.
Data processing methodology: The data on the balance of nitrogen for each country of the EU-15 are indicated in kilograms of nitrogen per hectare of utilised agricultural area (kg N/ha).
Geographical coverage: EU-15 consists of old Member States of the EU: Austria, Belgium, Denmark, Finland, France, Greece, Ireland, Italy, Luxembourg, Germany, The Netherlands, Portugal, Spain, Sweden, and the United Kingdom.
Information concerning data quality:
- Indicator advantages and disadvantages: Since new data for EU Member States are not available, we cannot speak about the Indicator advantages and disadvantages.
- Relevance, accuracy, robustness, uncertainty: Reliability of the indicator (archival data): /
Uncertainty of the indicator (scenarios/projections): /
- Overall assessment (1 = no major comments, 3 = data to be considered with reservation):
Completeness over time: 3
Completeness over space: 3