نوع مقاله: مقاله پژوهشی
نویسندگان
1 استادیار پژوهش بخش تحقیقات فنی و مهندسی، مرکز تحقیقات کشاورزی صفی آباد دزفول، خوزستان، ایران
2 استاد دانشکده مهندسی آب، دانشگاه شهید چمران، اهواز، خوزستان، ایران
3 دانشیار پژوهش موسسه تحقیقات فنی و مهندسی کشاورزی کرج، البرز، ایران
چکیده
کلیدواژه‌ها
عنوان مقاله [English]
نویسندگان [English]
This study was conducted to assess the ability of LEACHN model for predicting nitrate and ammonium in the soil profile under corn at the Safiabad Agricultural Research Center, over two growing years. Three irrigation levels (50, 75, and 100% water requirement) and three nitrogen fertilizer levels (150, 225, and 300 kg N ha-1) were applied through fertigation in three equal splits during the first irrigation, 6 to 8 leaves, and before flowering stages. The results of model calibration showed that nitrification and denitrification rates with 0.17, 0.004 per day and a dispersion coefficient equal to 200 mm provided the minimum mean bias error (MBE) and the maximum modeling efficiency (EF). Therefore, the MBE and EF values for nitrate varied from -2.09 to 3.89 and -0.1 to 0.88 respectively. However, model predictions for NH4 mobility through the soil profile were lower than that of nitrate mobility. Comparison between predicted and measured values did not show nitrate leaching below 60 cm in the soil profile in any treatments. Statistical indexes of MBE, EF, and coefficient of variation (CV) for soil moisture content predictions in different depths varied between 0.003 and 0.019, 0.24 and 0.73, and 5.8 and 17.9% respectively showing the high accuracy of model in prediction of soil moisture content.
کلیدواژه‌ها [English]
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