Impact of soil applied humic acid, zinc and boron supplementation on the growth, yield and zinc translocation in wheat

The experiment was conducted to optimize the level of humic acid, zinc and boron for better growth, enhanced yield and grain quality of wheat crop cultivated under field condition. Growth characteristics, yield and its components, and zinc concentrations in straw and grain were analyzed under two application rate of humic acid (0 and 10 kg ha-1), three level of boron (B0 = 0, B1 = 2 and B2 = 4 kg ha-1) and zinc (Zn0 = 0, Zn1 = 5 and Zn2 =10 kg ha-1). Results revealed that application of Zn at 10 kg ha-1 and B at 4 kg ha-1 combine with humic acid (10 kg ha-1) significantly increased yield and its components (except flag leaf area under humic acid application), and Zn contents in straw. The maximum plant height, spike length and grain filling rate were recorded at Zn2and B2 with humic acid application. Maximum grain yield was produced for Zn2 and B2 under humic acid application, which was associated with higher 1000-grain weight and biological yield. Maximum biological and straw yields were produced by application of Zn2 and B2 under humic acid fertilization. Maximum Zn contents in straw have been recorded for Zn2 and B2 under humic acid application, while maximum values of crude protein and Zn contents in Zn2 and B2 were statically same with Zn1 and B1 under humic acid application. Furthermore, the highest boron contents in grain were recorded for Zn2 and B2, and these values were statistically same with Zn2 and B1 under humic acid application. It is concluded that application of Zn2 and B2 in combination with humic acid could be a good agronomic practice to enhance the zinc content in straw and grain yield of wheat crop.