For T1−T4 see section ‘materials and methods’; leaf composition standards for apple based on mid-shoot leaves sampled at 120 DAFB (Bergmann and Neubert, 1976); sign (−) indicates deficiency level, while sign (+) indicates excessive level; the different small and capital letter in latest column indicate significant differences among ΣDOP indexes within each fertilizer and each cultivar(p ≤ 0.05 by LSD test), respectively