Response of bread wheat Cultivars to different levels of humic acid fertilizer in Tikrit city environment

A field experiment was carried out during the winter season 2022-2023 at the Field Crops Research Station (FCRS), located at Agriculture College, Tikrit University in a gypsum soil, to investigate the effect of humic acid on wheat growth, development, and yield. By Using the Randomized Complete Block Design (RCBD), Split-plot, with three replications, three levels of humic acid, 0, 20 and 40 kg.h-1, were located at the main block and fifteen cultivars of wheat, Sham 6, Sham 8, Eba 95, Eba 99, Tammuz 2, Tammuz 3, Karada, AlEzz, Maxibac, Abu Ghraib 3, Al-Fateh, Intisar, Latifa, Bohoath 22 and Rashid, were located at the secondary blocks, the experiment was applied. The number of days to expel the spikes, the number of active tillers, the number of spikes were calculated, and flag leaf area, plant height, and 1000 grains weight were measured. The result indicated that the level 40 kg.h-1 of humic acid significantly had a higher impact for all traits compared with the other two levels. As well as, Eba 99 and Tammuz 2 were significantly higher in all traits compared with other verities. The interaction between the third level and the two above-mentioned varieties was significant in most of the traits, especially the number of grains per spike (65.33 and 65.33 grains per spike-1) and the yield (7.85 and 8.42 tons h-1), respectively. According to the results, we suggested using 40 kg.h-1 and the cultivars Eba 99 and Tammuz 2 to plant in the gypsum soil conditions.