摘要
摘要:氨挥发是农田氮素损失的重要途径之一, 氨排放到大气中后与酸性气体反应形成二次气溶胶, 对空气质量有重要影响。本文研究了生物有机肥与化肥配施对稻田氨挥发的效果及主要机制, 旨在探索有效的稻田氨减排措施。本研究选取湖南省长沙县典型双季稻稻田, 开展为期两年4个稻季的田间试验, 设置不施氮肥(CK)、常规氮肥表施(CON)、生物有机肥替代40%氮肥+化肥表施(CB)、氮肥减量30%+生物有机肥替代40%减量氮肥+化肥深施(RBD) 4种施肥处理, 观测不同施肥处理下氨挥发动态及相关影响因素。两年的田间定位试验结果表明, 相同施氮量下, 采用生物有机肥与化肥配施显著降低了氨挥发(P<0.05), 且产量差异不显著。深施减氮结合生物有机肥与化肥配施, 氨挥发较CB处理进一步显著减少(P<0.05); 除2019年晚稻季外, 其余3个稻季CB处理与CON处理间水稻籽粒产量差异不显著。早、晚稻季, CB和RBD氨挥发累积量较CON处理分别降低25.2%~35.6%和63.2%~70.9% (P<0.05)。田面水铵态氮浓度与稻田氨挥发通量在各处理表现一致的变化趋势, 且呈现显著正相关(P<0.05), 表明施用生物有机肥及化学氮肥深施均可有效降低田面水铵态氮浓度, 从而减少氨挥发。综合两年的试验, 生物有机肥替代化肥结合深施减氮可减少稻田氨挥发达60%, 且不降低水稻产量, 可有效实现稻田氮肥减量、氨挥发减排。
关键词:氨挥发/
氮循环/
生物有机肥/
深施/
水稻
Abstract:Ammonia (NH₃) volatilization is one of the significant causes of nitrogen (N) loss in farmland. When NH₃ is released into the atmosphere, it reacts with acid gases to form secondary aerosols, which has a critical impact on air quality. This study aimed to simultaneously evaluate the effects and identify key mechanisms of combined applications of microbial organic fertilizer and chemical fertilizer on reducing ammonia volatilization in paddy fields. A two-year field experiment was conducted in a typical double-cropping rice field in Changsha County, Hunan Province. There were four fertilization treatments: no nitrogen fertilizer (CK), surface application of chemical nitrogen fertilizer (CON), a substitution of 40% chemical fertilizers with microbial organic fertilizers and surface application of chemical fertilizer (CB), and 30% reduction of chemical fertilizer with a substitution of 40% chemical fertilizers with microbial organic fertilizers and deep application of chemical fertilizer (RBD). NH₃ volatilization was measured using the intermittent closed chamber ventilation method in a two-year rice growing period (2019?2020), and the ammonium-N (NH₄⁺-N) and nitrate-N (NO₃^?-N) concentrations in the surface water were also measured. The results showed that under the same nitrogen application rate, NH₃ volatilization was significantly (P<0.05) reduced in CB treatment compared to CON treatment, and the rice grain yield for CB treatment was not significantly different from that for CON treatment in all the four rice seasons. NH₃ volatilization was lowest in RBD treatment compared to CON and CB treatments. The differences in rice grain yield between CON and RBD treatments was significant (P<0.05) for the late-rice season in 2019, while the differences were not significant for the remaining three seasons. In the early-rice season, the average cumulative NH₃ volatilization losses of CON, CB, and RBD were 33.1 kg(N)?hm^?2, 24.8 kg(N)?hm^?2 and 12.2 kg(N)?hm^?2, respectively. The NH₃ volatilization losses of CB and RBD decreased by 25.2% and 63.2%, respectively, compared to CON. In the late-rice season, the average cumulative NH₃ volatilization losses of CON, CB, and RBD treatments were 50.4 kg(N)?hm^?2, 32.4 kg(N)?hm^?2 and 14.7 kg(N)?hm^?2, respectively. The NH₃ volatilization losses of CB and RBD decreased by 35.6% and 70.9%, respectively, compared to CON. The magnitude of NH₄⁺-N concentrations in the surface water showed the same trend with the NH₃ volatilization across the treatments in the rice seasons. Furthermore, there were significantly (P<0.01) positive correlations between these two parameters, which indicated that application of microbial organic fertilizer as well as deep application of chemical nitrogen fertilizer played a role in reducing NH₄⁺-N concentrations in the surface water, and thus, reduced NH₃ volatilization. Based on the two-year field experiment conducted here, this study revealed that microbial organic fertilizer combined with deep application of nitrogen-reduced fertilizer can reduce ammonia volatilization by 60%, while maintaining rice yields. Thus, in conclusion, microbial organic fertilizers combined with deep applications of reduced nitrogen fertilizer can effectively reduce the application rate of nitrogen fertilizer and mitigate ammonia volatilization in double-cropping paddy fields.
Key words:Ammonia emissions/
Nitrogen cycle/
Microbial-organic fertilizer/
Deep application/
Rice



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