Effect of integrated nutrient management in some quantitative and qualitative characteristics of apple

The effects of conventional and integrated nutrient management (INM) systems were studied on some quantitative and qualitative characteristics of apple (Malusdomestica L. Borkh) trees of ‘Golden Delicious’. The experiment was carried out as a randomized complete block design with four replications at five locations over 2 years period on commercial apple orchards in northwestern Iran. Treatments consisted of T1 (conventional method) and T2 (INM based on soil test and plant analysis). The results indicated significant differences in SPAD chlorophyll index between the different management systems. INM treatment produced 10% higher leaf chlorophyll content than the conventional method. These findings revealed evidence of major differences in the leaf N, K, Ca, Fe and Zn nutrient contents between conventional and INM fertilization of grown apple trees. The nutrient balance indices (NBI) calculated by DRIS norms of T1 and T2 treatments were 87.92 and 48.32, respectively. INM system increased fruit protein and Ca/Mg ratio than the conventional method. The comparison of the nutrients concentration and some fruit quality parameters with international standards showed that in both treatments, fruit protein, P, Mg, Fe, Zn and Cu nutrients were higher than the standard values but the concentrations of K, Ca and Mg were lower than standard values. Furthermore, N/Ca ratio in both treatments was higher than the standard value probably due to the extensive former application of nitrogen fertilizers in apple orchards. It can be concluded that fertilization of apple based on INM system is effective in promoting fruit quality as well as trees health.