The concept of the Georgikon Map-Server has been conceived and realized in the project “Management alternatives for reducing diffuse phosphorus load from the watershed of Lake Balaton” (No.: 3/024/2001 NKFP; 2001-2004). One of the main objectives was to build a coherent watershed database and to publish it in a way that it should be able to meet different levels of demand on information stretching between the unprofessional and the scientific ones. The created GIS database of existing and newly generated data has been published (http://www.georgikon.hu/nkfp/szerver.htm). The concept has been developed in a new project “Development of an erosion model for the watershed of Lake Balaton accessible through the Internet and adaptation for other environments” (No.: GVOP-3.1.1.-2004-05-0383/3.0; 2005-2006). It aims at 1) developing a comprehensive data base for the whole watershed that allow detailed assessment of soil properties (first of all erodibility and infiltration); 2) developing a user interface to help farmers and advisors to determine basic variables of erosion (slope length and gradient); 3) developing a model that makes possible to dynamically assess transition of sheet and rill erosion; 4) publishing data that make directly visible spatial joins of on- and off- site effects of erosion; and 5) developing a system that makes possible to plan and service environmental sound precision farming (contour cultivation, variable fertilization within fields). This publication presents results of the first objective and some preliminary results of the objectives 2, 4 and 5. The whole watershed is 5775.0 sqkm and the agricultural area is 3089.1 sqkm as derived from the CORINE land cover database. 1:25,000 scale soil maps exist for the whole agricultural area of the watershed (Géczi-maps). They were compiled in the late 1950ies and early 1960ies by using earlier maps (Kreybig-maps) as a base. Géczi-maps contain rather limited information but basic physical data (physical type, stoniness, soil water table) and necessity of liming are available layer by layer down to 150 cm. 1:10,000 soil maps were compiled between the 1970ies and late 1980ies with the most intensive mapping in the late 1980ies for part of the watershed. The protocols of the soil samples contain basic physical (soil physical type, liquid limit, stoniness, soil water table) and chemical data (pH, humus content, exchangeable acidity) layer by layer down to 150 cm. All the available 1:25,000 maps have been digitalized and 1:10,000 maps have been digitalized for 275.4 sqkm and additional topographic information (scale 1:10,000) has been added to the sampling points (slope, distance from a stream, elevation). Statistical procedure has been developed to assess more detailed soil pattern for areas where 1:10,000 soil maps are not available with help of 1:25,000 soil maps and detailed topographic information. One of the extension firms that operate in the watershed has a database that contain long time series of the nutrient status of the topsoil and the database overlaps with the watershed of the Lake Balaton (231.7 sqkm). Database of field management and soil nutrient tests was compiled in an earlier study for the period of 1978-1985 (918.3 sqkm). Statistical procedure has been developed to assess soil nutrient status depending on the information of assessed or real 1:10,000 soil maps and on fertilization. Data on saturated hydraulic conductivity are rather sparse for the soils of the watershed and data on erodibility are even sparser. Limited data sets and relationships taken from the literature have been used to asses these soil properties in great detail with help of maps described above. It is possible, based on the developed detailed database, to prioritize field-scale actions of soil protection within catchments and to prioritize catchments-scale actions within the watershed. Georgikon Map-Server may be good example of creating and managing environmental information systems. The continuous development of the map-server is planned in order to establish a complex expert system for the watershed.