Can Efficient Irrigation and Nitrogen Management Practices Contribute to Nitrate Reduction in Groundwater under Intensive Farmer-Managed Vegetable Fields in Slovenia Catchments?

Groundwater is a very important source of drinking water in Slovenia. However, the intensification of agriculture through the use of nitrogen (N) fertilizers and organic manure from livestock (pig farms) to enhance crop yields may be one of the causes of groundwater contamination through nitrate leaching. It is predicted that intensive vegetable production is the major cause of nitrate contamination in the Ljubljana aquifer which is the major source of drinking water in Ljubljana, Slovenia. The Project. Slovenia aims to meet the EU Water Framework Directive (2000/60/EC) and national standards for good quality groundwater status by 2013 while maintaining an intensive agriculture production. A Technical Cooperation Project (TCP) SLO5002 was funded by IAEA to help improve the capabilities of the Slovenia Counterpart institutes to address nitrate (and also) pesticides in drinking water by establishing a monitoring system for soil water balance, and for pesticide and nitrate leaching from agricultural benchmark sites in Slovenia catchments. The objective of the study is to assess how different irrigation, nitrogen and cropping system management strategies could help reduce nitrate leaching while sustaining yields in a farmer-managed vegetable field using farmers' (one time fertilizer application before planting and irrigating shortly after planting) and improved practices (scheduled irrigation and fertilization) in a benchmark site in Sneberje, Slovenia. The project also aims to transfer knowledge to the stakeholders. Nitrogen-15 fertilizer was used as a tracer to monitor N acquisition by plants and nitrate movement in the soil. Soil water was monitored using 2 capacitance probes (EnviroScan and the Time Domain Reflectometer). The IAEA provided experts, training, equipment, stable and radioactive tracers and consumables and the Government of Slovenia executed the Project