Foliar nutrition diagnosis of red Fuji apple in western Henan province

This study aimed to reveal the relationships between mineral nutrients in Fuji apple leaves to provide a scientific basis for balanced fertilization. Foliar samples were taken from 22 red Fuji apple orchards in western Henan province and foliar nutrition diagnosis was done using Diagnosis and Recommendation Integrated System (DRIS) method. The results showed that the optimum concentrations of N, P, K, Fe, Mn, Cu, and Zn in leaf were 22.54±3.00 g/kg, 2.42±0.28 g/kg, 9.31±1.40 g/kg, 104.47±15.03 mg/kg, 33.89±5.77 mg/kg, 3.38±0.39 mg/kg, and 29.71±4.91 mg/kg，respectively. The optimum ratio of N:P:K was 1:0.08-0.14:0.31-0.55. The variation of parameters, viz. N/P, K/N, K/P, Cu/N, P/Mn, Cu/P, P/Zn, K/Fe, K/Cu, Zn/N, and K/Zn for DRIS were larger in the high yield orchards (C.V. ranging from 20.44% to 40.82%) compared to low yield orchards (C.V. ranging from 8.69% to 23.95). The Nutrient Imbalance Index (NII) was 39 in the high yield orchards and 88 in the low yield orchard. The orchards with Fe, Mn, and Zn deficit accounted for 86%, 82%, and 50% of total studied orchards, respectively. The mineral nutrient unbalance were more serious in low yield orchards compared with higher yield orchards. The most deficient elements were Fe, Mn and Zn in the red Fuji apple orchards in western Henan province.