Assessment of Gaseous Nitrogen (NH3 and N2O) Mitigation After the Application of a Range of New Nitrogen Fertilizers in Summer Maize Cultivation

Abstract

In order to evaluate the potential of a range of new nitrogen fertilizers in comparison with the conventional fertilization to mitigate ammonia (NH3) and nitrous oxide (N2O) emissions, a field experiment was conducted to investigate NH3 volatilization and N2O emissions from the summer maize field and the relevant driving factors under the different nitrogen fertilizer treatments. Five new varieties of nitrogen fertilizers including the urea ammonium (UA), stability urea with dicyandiamide and hydroquinone (UHD), sulfur coated urea (SCU), urea formaldehyde compound fertilizer (UF) and organic fertilizer (OF) were applied in this experiment, and conventional fertilization (compound fertilizer + urea, CK) was used as the control. The nitrogen amount of 300 kg·hm-2 was applied in all treatments. Correlation analysis results showed that both NH3 volatilization and N2O emissions were influenced by environmental factors. They were negatively correlated with soil water-filled pore space (P<0.05). Moreover, N2O emissions were positively correlated with soil nitrate nitrogen (P<0.01). Regression analysis showed that N2O emissions were mainly determined by the soil nitrate content, while NH3 volatilization was mainly dependent on the values of soil ammonium nitrogen. Compared with CK, in addition to UA, other fertilizer treatments decreased the NH3 volatilization, especially the UF and OF treatments decreased NH3 volatilization by up to 37%-43%, while all treatments had no significant difference in N2O emissions. Considering the total gaseous nitrogen losses (NH3 volatilization + N2O emissions), in comparison with CK, the UHD, SCU, UF and OF were reduced by 9%, 5%, 30% and 23%, respectively, while the UA was increased by 3%. Therefore, considering environmental benefit under this experimental condition,urea formaldehyde compound fertilizer and organic fertilizer were more suitable for maize cultivation.