Field Balances Of Organic Apple Orchards In Two Regions Of Germany

Summary in the original language of the document

Fertilizers used for organic apple production contain multiple nutrients with a nutrient composition that differs from that of the harvested products. Some plant protection agents also contribute to an input of nutrients. To gain information on the status of nutrient balances and to identify potential causes for imbalanced nutrient flows, a survey was conducted in two main apple growing regions of Germany. The current management was analysed based on field balances of apple orchards using data spanning a five-year period. The averages showed small surpluses of P (3 kg ha-1), a deficit of K (-10 kg ha-1 a-1) and stronger surpluses of N (26 kg ha-1), Ca (36 kg ha-1) and S (50 kg ha-1). Base fertilizers had a liming effect, while some commercial fertilizers, pesticides and the offtake of harvest products had an acidifying effect. The severity and range of nutrient imbalances differed between the regions and was dependent on the kind of fertilizers (base or commercial) and pesticides used.