Field experiments of nitrate treatment on ‘Fuji’ trees
For field experiment, 2-year-old ‘Fuji’ trees were selected as
experimental material. ‘Fuji’ trees were planted at National Engineering
Research Center for Apple of Shandong Agricultural University. Line
spacing × plant spacing is ~ 2 meters × 0.7 meters. Each
line contains 11 trees. Since April 2018, the trees were treated with
10, 30, 60 or 120g
KNO3 fertilizer per
plant, respectively, with KCl was added to maintain the same
K+ concentration. KNO3 fertilizer was
applied to the left side of the tree, near the root. The treatment was
performed once a month until June. KNO3 fertilizer was
purchased from Shandong Agricultural University Fertilizer Technology
Co., Ltd. (Tai’ an, China).