Study of the nitrate leaching from Urea and SCU, irrigation by Lysimeter.

Nitrogen fertilizer and irrigation management have the important role to control nitrate leaching. In order to compare nitrate leaching and variation of nitrate concentrations rate in soil profil for two sources of nitrogen fertilizer : Urea and SCU (Urea coated with solfour)by Lysimeter an experiment waz carried out at Kahriz station of Uromie for three years.4 Lysimeters were used to measure crop evaportranspiration and nitrate leaching of wheat for two years and corn for one year in different growth stages. Two Lysimeters with area of 1.5 m2 were used for Urea fertilizerصصصand the number1was irrigated according to obtain potantial evaportranspiration and the number 2 was irrigated according to local conditions. The other two Lysimeters with area of 1.8 m2 were used for SCU fertilizer and the number 3 was irrigated according to obtain potantial evaportranspiration and number 4 was irrigated according to local conditions.400 m2 around of each Lysimeter was colthvated such as Lysimeter area. The evapotranspiration of each production determine from measurment of irrigation water and amount of principal and drainage water for each lysimeter. The results have showed the mean wheat evapotranspiration for 4 Lysimeters in order was 492.5, 492.5, 484.4 and 498.1 mm. For the fertilizer source maxiumum grain yield was obtained from Urea fertilizer (8 t/ha). For the irrigation regim maxiumum grain yield was obtained from the irrigation to obtain potantial evaportranspiration (8.5 t/ha). Also the results have showed the mean corn evapotranspiration for 4 Lysimeters in order was 683.8, 668.8, 807.8 and 796.1 mm. For the fertilizer source, maxiumum grain yield was obtained from SCU fertilizer (10.55 t/ha). For the irrigation regim maxiumum grain yield was obtained from the irrigation to obtain potantial evaportranspiration (10.58t/ha). Key words : corn, Evapotranspiration, Lysimeter, nitrate leaching SCU, sources of nitrogen fertilizer, Urea, water use efficiency, wheat, yield.