Mineral Nitrogen Distribution in the Soil Profile and Nitrogen use Efficiency in wheat

The role of nitrogen in plant nutrition has been studied more than any other elements. Wheat with scientific name of (Triticum aestivum L.), is one of the oldest and the most widely used cultivated plants in the world. The food consumption of wheat per capita in the Iran Based on household expenditure is estimated 135 kg for urban areas, 185 kg in rural areas and 151 kg for the whole country. Soil mineral nitrogen is in form of elemental nitrogen, nitrate nitrogen, ammonia nitrogen and organic nitrogen. Nitrogen is absorbed by plants in two forms: Ammonium (NH4) and nitrate (NO3-). It may be defined the leaching process as the moving of dissolved nitrogen in a certain volume of soil, leaving the root zone into the depth. The Nitrogen use efficiency (NUF) and Nitrogen Apparent Recovery Factor (NARF) in Iran is low compound with another country. In this experiment total nitrogen and micronutrients analysis was performed. More over in this study, 7 treatments N1= (no Nitrogen), N2 (N=90kg/ha urea), N3 (N=120kg/ha urea), N4 (N=150kg/ha urea) N5 (N=90kg/ha SCU), N6 (N=120kg/ha SCU), N7 (N=150kg/ha SCU) and 3 replications were conducted in a randomized complete block design. Plant harvesting was done at 6 square meters of floor. The result showed that the higher grain yield 5630 kg/ha was related to N4 treatment. The higher GPC 9.58% was related to N7 treatment. The higher NUE 13.56 kg/kg and higher NARF 17.62% was related to N2 and N4 respectively the obtained results indicated that the Soil nitrate loss by leaching. The highest concentrations of nitrate in the soil was also at the depth of 0-20 and 20-40 cm.