Influence of Mineral Fertilizer, Farmyard Manure, Natural Zeolite, and their Mixture on Fruit Quality and Leaf Micronutrient Levels of Apple Trees

Abstract

Adequate soil conditions and fertilization as a cultural practice are the basis of fruit crops production. This study was conducted in 2011 and 2012 to determine impact of soil application of complex nitrogen, phosphorus, and potassium (NPK) mineral fertilizer alone and its mixture with cattle manure (M) and natural zeolite (A) on yield, fruit physico-chemical traits and leaf micronutrient amounts at 120 days after full bloom (DAFB) in "Idared" and "Melrose apples grown on heavy and acidic soil under Serbian conditions. Results showed that NPK increased yield in "Idared" and both NPK+A and NPK+M in "Melrose." Fertilizer applications were not influenced by fruit physico-chemical attributes, but differences between cultivars were significant. Fertilizers induced changes of leaf micronutrients amount, but effect was not consistent. In "Idared," NPK+A and NPK+M mixtures improved amounts of the most micronutrients, whereas in "Melrose," NPK and mixture NPK+A+M increased leaf micronutrients in more cases. According to deviation from optimum percentage (DOP and Sigma DOP indexes), excessive leaf iron (Fe) and zinc (Zn) was found and deficiency of manganese (Mn), copper (Cu), and boron (B). "Melrose" exhibited much better balanced nutritional values for nutrients as compared to "Idared," whereas NPK+M in "Idared" and NPK alone in "Melrose" promoted better balanced nutritional values. Since the impact of nutrients on the studied features is not consistent, more research will need to be conducted to investigate the long-term effect of NPK alone or in mixture with natural zeolite and manure fertilization on apples.