Evaluation of the effect of nitrogen fertilizer and irrigation schedule on soil CO2 flux, photochemical properties and corn yield (Single Cross 704)

With the Green Revolution and crop yield increase per unit area, the use of pesticides and chemical fertilizers, especially nitrogen, has grown significantly. The aim of this study was to evaluate the effects of nitrogen fertilizer levels and irrigation schedule on soil CO2 emission, photochemical characteristics and corn yield. The study a 3×2 factorial was conducted in a randomized completely block design, includes nitrogen fertilizer treatments at three levels 0 (N1), 150 (N2) and 350 (N3) kg of urea fertilizer per hectare, and two Irrigation schedules, immediately (I1) and two days after fertilization (I2). The experiment was conducted during 2016-2017 cropping season at the research farm of Sari Agricultural Sciences and Natural Resources University. According to the results, different levels of nitrogen fertilizer had no significant effect on soil CO2 flux, while irrigating after fertilization significantly affected CO2 emission (P ≤ 0.01). The highest carbon dioxide flux was observed in the tenth stage of sampling in I1 irrigation with 366.42 mgC.m-2.h-1, while the lowest occurred on first sampling stage in I2 irrigation treatment with 45.86 mgC.m-2.h-1. While, the effect of different levels of nitrogen fertilizer showed a significant difference in the yield and photochemical properties of corn (P ≤ 0.01). So that the highest and lowest yields achieved by N3 (36 kg m2) and N1 (13.4 kg m2) nitrogen fertilizer levels, respectively. In conclusion, although irrigation schedule had no effect on yield or photochemical properties of corn, but it assumes by fixation of nitrogen fertilizer immediately on the soil tends to increase soil CO2 fluxes through plant and soil microorganisms activities.