农田土壤施用系列新型氮肥后气态氮(NH3和N2O)减排效果比较:以夏玉米季为例

为了解不同品种新型氮肥相对常规施肥其氨(NH3)和氧化亚氮(N_2O)的减排效果,本文通过田间原位试验同步研究了夏玉米生长季氮肥施用后的农田NH_3挥发和N_2O排放及其主要驱动因子.以常规施肥(复合肥+尿素,CK)为对照,设置了5个肥料处理,分别为脲铵氮肥(UA)、稳定性复合肥料(UHD)、硫包衣氮肥(SCU)、脲甲醛复合肥(UF)和有机肥(OF),施氮量(以N计)均为300 kg·hm~(-2).相关分析结果表明,氨挥发和N_2O排放受环境因子影响,均与土壤WFPS呈显著负相关(P0.05),N_2O排放还与土壤硝态氮呈极显著正相关(P0.01).进一步回归分析表明,N_2O排放(F_(N_2O))主要取决于土壤硝态氮(x)含量的变化,而氨挥发(F_(NH_3))主要取决于土壤铵态氮(x)含量的变化.与CK相比,除了UA,其它肥料处理都降低了土壤的氨挥发,尤其是UF和OF处理减少了37%~43%.但对于N_2O排放,所有处理与CK皆无显著差异.进一步计算每种处理氨挥发和N_2O的气态氮损失总量,与CK相比,UHD、SCU、UF和OF分别减排了9%、5%、30%和23%,而UA增加了3%.

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

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.