Abstract
The influence of organic fertilizers on nutrient balance, yield, soil nutrient and organic matter-results of a 10-year field study. Abstract Nutrient availability is an important factor in apple cultivation and, especially in organic production, the use of organic fertilizers can lead to a deficit or excess of individual nutrients, and one-sided nutrient supply can affect production. Therefore, fertilization measures should be adapted to the crop to avoid negative inputs into the environment. Therefore, soil tests are carried out regularly in apple cultivation to check the fertilization measures that have been carried out and, in addition, the calculation of the nutrient balance can also be used. In this study, seven different treatments were applied to the apple variety 'Golden Delicious' over a period of 10 years. In addition to an unfertilized control and a conventional variant with ammonium sulfate, three different organic fertilizers were used. On the one hand, one variant was fertilized with compost and a second variant with a combination of compost + Nutristart, while on the other hand the fertilizer Azocor 105 was applied. The fertilizer Azocor 105 was used in three variants, comparing the methods of mulching and tillage for weed control with the conventional method, ploughing and brushing. Overall, both nutrient balances and yields were evaluated, as well as the results of Nmin analyses. In addition, the results of the soil analyses of 2009 and 2019, for the evaluation of the P, K, Mg and organic matter in the soil, were used. The evaluations show that the nutrient balances are unbalanced for all variants, and no significant difference can be found between the variants in terms of yield. However, a tendency towards higher yields can be observed for the ammonium sulfate and Azocor 105 variants. In the results of the Nmin analyses, significant differences between the variants can be observed in some years, while the P, K, Mg and organic matter in the soil was increased mainly for the variants compost and compost + nutristart. Finally, the fertilizer Azocor 105, compared to the other organic fertilizers, was found to have the most positive effects on yield and nutrient availability.