追氮方式对夏玉米土壤N_2O和NH_3排放的影响  

Impact of fertilization method on soil nitrous oxide emissions and ammonia volatilization during summer maize growth period

作　　者：刘敏[1] 张翀[1] 何彦芳 高兵[1] 苏芳[1] 江荣风[1] 巨晓棠[1] 

机构地区：[1]中国农业大学资源与环境学院,北京100193 [2]环境保护部环境工程保护中心,北京100012

出　　处：《植物营养与肥料学报》2016年第1期19-29,共11页Journal of Plant Nutrition and Fertilizers

基　　金：国家自然科学基金(41471190;41301237);中国博士后科学基金(2014T70144)资助

摘　　要：【目的】研究氮肥与硝化抑制剂撒施及条施覆土三种追施氮肥方式下土壤N2O和NH3排放规律、O2浓度及土壤NH+4-N、NO-2-N和NO-3-N的时空动态,揭示追氮方式对两种重要环境气体排放的影响及机制。【方法】试验设置3个处理:1)农民习惯追氮方式—撒施(BC);2)撒施添加10%的硝化抑制剂(BC+DCD);3)条施后覆土(Band)。3个处理均在施肥后均匀灌水20 mm。在夏玉米十叶期追施氮肥后的15天(2014年7月23日至8月8日)进行田间原位连续动态观测,并在玉米成熟期测定产量及吸氮量。采用静态箱-气相色谱法测定土壤N2O排放量,土壤气体平衡管-气相色谱法测定土壤N2O浓度,PVC管-通气法测定土壤NH3挥发,土壤气体平衡管-泵吸式O2浓度测定仪测定土壤O2浓度。【结果】农民习惯追氮方式N2O排放量为N 395 g/hm2,NH3挥发损失为N22.9 kg/hm2,同时还导致土壤在一定程度上积累了NO-2-N。与习惯追氮方式相比,添加硝化抑制剂显著减少N2O排放89.4%,使NH3挥发略有增加,未造成土壤NO-2-N的累积。条施覆土使土壤N2O排放量显著增加将近1倍,但使NH3挥发显著减少69.4%,同时造成施肥后土壤局部高NO-2-N累积。条施覆土的施肥条带上土壤NO-2-N含量与N2O排放通量呈显著正相关。土壤气体的O2和N2O浓度受土壤含水量控制,当土壤WFPS大于60%时,0—20 cm土层中的O2浓度明显降低,而N2O浓度增加,土壤N2O浓度和土壤O2浓度间呈极显著负相关。各处理地上部产量及总吸氮量差异不显著。【结论】土壤NO-2-N的累积与铵态氮肥施肥方式密切相关,NO-2-N的累积能够促进土壤N2O的排放,且在条施覆土时达到显著水平(P<0.05)。追氮方式对N2O和NH3两种气体的排放存在某种程度的此消彼长,添加硝化抑制剂在减少N2O排放的同时会增加NH3挥发,条施覆土在显著减少NH3挥发的同时会显著增加土壤N2O排放。在条施覆土基础上添加硝化抑制剂,有可能同时降�【Objectives】The temporal and spatial patterns of soil NH＋4-N,NO-2-N and NO-3-N content variation under different nitrogen fertilization methods,and the soil air N2 O and O2 concentrations were investigated in the present study. The aim is to explore the mechanism of soil NH3 volatilization and N2 O emission. 【Methods】The tested N fertilization methods were： 1） local farmers＇ conventional practices in which urea is broadcasted on soil surface followed by irrigation（ BC）,2） broadcasting urea on soil surface and followed by the application of nitrification inhibitor DCD on soil surface（ BC ＋ DCD）,3） band application of urea in the middle of two adjacent maize rows and backfilled with soil（ Band）. Field experiment was conduct in a summer maize field from July 23 to August 8,2014. Crop yield and nitrogen uptake were measured in the ripe period. Soil N2 O emissions weremeasured with static chamber-gas chromatograph（ GC） method and NH3 volatilizations with PVC tube-venting method. Soil N2 O and O2 content were measured with soil-air equilibration tube-GC and soil-air equilibration tubepump determinator,respectively. 【Results】The N2 O emission and NH3 volatilization induced by farmers＇ practice was N 395 g / hm2 and N 22. 9 g / hm2 respectively,the soil NO-2-N showed accumulation to some extend. Compared with BC,the application of DCD precluded the accumulation of soil NO-2-N in soil,reduced N2 O emission by89. 4%,whereas increased NH3 volatilization by 27. 1%; By contrast,band application of urea induced high soil NO-2-N accumulation in the fertilizer band,doubled N2 O emission,whereas reduced NH3 volatilization by 69. 4%.O2 and N2O concentration is soil air was regulated by WFPS. When WFPS was over 60%,O2 concentration reduced while N2 O concentration increased significantly in the 0- 20 cm soil layer. A negative relationship was observed between N2 O and O2 concentration in soil air. There was nether significant difference among the three treatments in maize yield,nor total

关 键 词：追氮方式 N2O排放 氨挥发 硝化抑制剂(DCD) 土壤NO-2-N累积 

分 类 号：S513[农业科学—作物学]