APPLICATION OF THE SZŰCS ALGORITHM AS AN AID FOR ORCHARD MINERAL FERTILIZATION

Although it is very important to know the quantity of macronutrients an orchard extracts from the soil, this alone is not sufficient to determine the right amount of fertilizer that growers have to apply annually. In this regard, the Szűcs algorithm may provide effective help. This algorithm considers many parameters, including the quantity of mineral elements the fruit grower removes from the orchard, leaf mineral diagnosis and physical and chemical characteristics of the soil. This work concerns the application of the Szűcs algorithm to data from two hazelnut orchards and a sweet cherry orchard, to calculate the quantity of N, P₂O₅ and K₂O (kg ha^-1 year^-1) to be supplied by means of mineral fertilization. The quantities of the three nutrients to be replaced varied among species. In cherry trees, the difference in fertilizer recommendation between the cultivars (‘Droganova’ and ‘Ferrovia’) seemed to be related to the higher yield of one of them only for N and P₂O₅. In ‘Tonda Gentile delle Langhe’ hazelnut orchards, differences in fertilizer recommendation were due to the different soil conditions and the different yields of the orchards.