Best Management Practices for Sustainable Crop Nutrition in Bulgaria

In 2008, a 5-year project was established in Bulgaria with the general goal of improving cultivation systems in Bulgaria’s agriculture through efficient and sustainable use of plant nutrients. The project involves five Bulgarian organizations: The University of Forestry, Agricultural University, “Nikola Poushkarov” Institute of Soil Science, Executive Soil Resources Agency (Ministry of Agriculture), and the National Plant Protection Service (Ministry of Agriculture). About 50 researchers and discipline specialists take part in the project. Project activities include: 1) Evaluation of soil nutrient status through summarization of past national soil surveys and more recent localized regional surveys; 2) Systematic summarization of past relevant soil fertility research and identification of information gaps; 3) Nutrient omission/addition plot trials on target crops; 4) Development of tools for site-specific nutrient management that deliver updated recommendations to farmers and farmer advisers; 5) Outreach activities to assure appropriate use of the developed tools.

After conducting a soil test survey of pilot regions in Bulgaria in 2009, survey activities in 2010 were focused on mapping the soil survey data and creating a GIS database with soil and field data attributes. Layers were then created with three classes (low, medium and high content of P and K) and the zones with low or medium P or K were overlaid with agricultural areas to reflect areas with P and K deficiency.

In 2009, an Access database was structured for past soil fertility research and to accommodate new project data. In 2010, data obtained from long-term crop field experiments after 1974 were entered into the database. The archive now consists of data from 87 experiments at 26 sites and 8 main soil types.

In 2010, 28 omission/addition field plot trials (NPK or NPKMg as complete treatments) were conducted following the same protocol as in 2009. Crops tested were wheat, barley, maize, sunflower, potatoes, tomatoes, pepper, apricots, peaches, chokeberry, and vine grape. Results in 2010 from the field trials in most cases confirm the tendencies found in 2009 — most of the tested crops respond to fertilization with the NPK treatment producing the highest yields in many sites. Highly significant interactions among nutrients are being frequently measured. The project is well on its way to creating the foundation for new fertilizer best management practices for Bulgaria. IPNI-14