[Studies on the effects of a steady or rotating use of permanent grassland on its plant population and the number of species in the Lenzener Elbtalaue - First results]

abandoned land affouragement en vert agriculture extensive analyse de sol brandenbourg brandenburg brandenburgo conduite des herbages continuous cropping crop yield cultivo continuo culture continue disponibilidad de nutrientes ecologia ecologie ecology encuestas especies extensive farming fallow systems farmland ferme pilote fertilidad del suelo fincas experimentales grassland management grazing lands habitat improvement land management land use ley farming leys manejo de praderas manejo del suelo mejoramiento del habitat mise en valeur du sol nitrogen content no pastoreo nutrient availability pastizal permanente permanent pastures pilot farms pradera temporal prairie permanente prairie temporaire rendement des cultures rendimiento de cultivos sistemas con barbecho soil fertility soil management soil testing sostenibilidad species surveys sustainability teneur en azote terre agricole tierras abandonadas tierras de pastoreo utilisation des terres zero grazing