%A Dr. Harriet Gruber %A Uwe Thamm %J Ende der Nische, Beitr?ge zur 8. Wissenschaftstagung ?kologischer Landbau %T Entwicklung der Grundn?hrstoffgehalte in einem schwach lehmigen Sandboden Nordostdeutschlands nach langj?hriger ?kologischer Bewirtschaftung %X The following paper shows the impact of organic farming on the development of contents of phosphorus, potassium and magnesium in the soil. The basis is a six-year crop rotation with animal manures (85 dt/ha/a) in the location of G?lzow (Mecklenburg- Prepomerania). From 1993 to 2004 samples of soil were taken with aan soil auger in a depth between 0 and 30 cm. The discussion of changes in chances of the nutrient contents nutriens content is connected with nutrient balances. As a result, nutrients bilances, witch are in balance. On this time the the contents of potassium shows decreasing tendency. Organic farming does notno lead to lower contents of phosphorus and magnesium. The impacts of soil and year are high. %K Pflanzenbau, Bodenfruchtbarkeit, Pflanzenern?hrung %E J He? %E G Rahmann %D 2005 %I kassel university press GmbH, Kassel %L orgprints3454