Effect of Humic Acid and the Level of Nano and Conventional Nitrogen on the Available and Absorbed Nitrogen Element and the Potato Yield

A field experiment was carried out during the fall season of 2021 at the research station of the University of Anbar - College of Agriculture, to find out the effect of humic acid and the level of nano and conventional nitrogen in the prepared and absorbed nitrogen element and the yield of potato cultivar Rivera, the experiment included two factors: the two sources of nitrogen and their levels, represented by the traditional nitrogen NT₁, NT₂ at the level of 150 and 300 kg N ha^-1 in the form of (urea fertilizer) and the nano-nitrogen, Nn₁, Nn₂, Nn₃ at level 15, 30 and 45 kg N ha^-1 sequentially in addition to the control treatment. The second factor was the addition of humic acid H₁ at the level of 100 kg ha^-1 in addition to the control treatment (without addition) and according to the RCBD randomized complete block design with three replications. The results were statistically analyzed and the means of the coefficients were compared at the 0.05 probability level to test for the least significant difference. The results of the study showed the following: The treatments achieved a remarkable variation in nitrogen content in the vegetative part and tubers, and the interaction coefficients between humic acid and urea achieved the highest nitrogen content in the vegetative part and tubers, as well as the total nitrogen uptake. While the Nn₃H₁ treatment achieved the highest value of the marketing outcome. The availability of ammonium and nitrate in the soil increased with the increase in fertilization levels for the two fertilizer exporters, and the highest availability was achieved in the presence of humic acid. There was a significant effect of adding humic acid on (AE), which amounted to 59.0% compared to 49.0%, and the lowest decrease in field efficiency was with conventional nitrogen fertilizer treatments compared to the highest field efficiency achieved with nano-nitrogen addition treatments. While the highest value of the field efficiency when treating the interference was Nn₃H₁. The availability of ammonium and nitrate in the soil increased with the increase in fertilization levels for the two fertilizer exporters, and the highest availability was achieved in the presence of humic acid. There was a significant effect of adding humic acid on AE, which amounted to 59.0% compared to 49.0%, and the lowest decrease in field efficiency was with conventional nitrogen fertilizer treatments compared to the highest field efficiency achieved with nano-nitrogen addition treatments. While the highest value of the field efficiency when treating the interference was Nn₃H₁. The availability of ammonium and nitrate in the soil increased with the increase in fertilization levels for the two fertilizer exporters, and the highest availability was achieved in the presence of humic acid. There was a significant effect of adding humic acid on (AE), which amounted to 59.0% compared to 49.0%, and the lowest decrease in field efficiency was with conventional nitrogen fertilizer treatments compared to the highest field efficiency achieved with nano-nitrogen addition treatments. While the highest value of the field efficiency when treating the interference was Nn₃H₁. The addition of humic acid achieved an efficient nitrogen recovery NUE amounted to 60.13% compared to 44.45%. The treatment of adding nano-nitrogen Nn₁, Nn₂ and Nn₃ recorded recovery efficiency of the element amounted to 82.47, 80.14 and 77.89% respectively, and was superior to the traditional fertilization treatments NT₁, NT₂, which amounted to 39.72, 29.81% respectively, while the dual interaction treatments achieved the highest recovery efficiency of the element which reached to the treatments of the nano-source Nn₁H₁, Nn₂H₁, Nn₃H₁ (95.25, 92.08 and 88.71%) sequentially. Compared with the levels of the traditional source NT₁H₁, NT₂H₁ (45.35 and 31.95%), respectively.