N2:O emissions from a cultivated Andisol after application of nitrogen fertilizers with or without nitrification inhibitor under soil moisture regime

IntroductionNitrousoxide (N2 O)isoneoftheenvironmentallyimportanttracegases ,currentlyaccountingfor 2 %—4 %oftotalGreenhouseWarmingPotential (GWP ) .Itisalsoinvolvedinthedepletionofstratosphericozone .SoilhasbeenknownasthemajorsourceofN2 O ,accountingfor 6 5 %oftotalglobalemissions(Prather,1995 ) .Thus,reducingN2 Oemissionsfromsoilsisamaintaskfortheprotectionoftheglobalatmosphere .N2 Oisproducedastheresultofsoilmicrobialprocesses ,primarillybynitrification ,whentheoxidationhappensofNH+…     

氮肥管理措施对黑土玉米田温室气体排放的影响

采用静态箱-气相色谱法研究了不同氮肥管理措施(农民常规施肥、减氮20%、添加硝化抑制剂、施用控释肥)对黑土玉米田温室气体排放的影响.结果表明:黑土玉米田施肥(基肥和追肥)后1~3d出现N2O排放峰,施肥后16d内N2O排放量占生育期总排放量的28.8%~41.9%.减施氮肥20%显著降低土壤N2O排放,生育期内的N2O累积排放量减少了17.6%~46.1%,综合温室效应降低30.7%~67.8%,温室气体排放强度降低29.1%~67.0%.等氮量投入时,添加吡啶抑制剂土壤N2O排放量、综合温室效应和温室气体排放强度最低.玉米拔节~乳熟期出现了较强的土壤CO2排放,黑土玉米田是大气中CH4的一个较弱的“汇”,施氮和添加硝化抑制剂对黑土玉米田CO2排放和CH4吸收没有显著影响.添加硝化抑制剂和施用控释肥不影响玉米产量.在本试验条件下,减氮20%并添加吡啶抑制剂在保证玉米产量的同时, 减排增收效果优于其他施肥措施,适宜在黑土区玉米种植中推广使用.     

Effect of fertilizer and water content on N2O emission from three plantation soils in South China

Introduction Nitrousoxide(N2O)isoneofthemostimportantgreen housegases,whichcontributestoglobalwarmingand consumptionofO3inthestratosphere(Breuer,2000,Solomon,1999).N2Oconcentrationincreasesatarateof0.25%peryear,57%ofwhichisderivedfromthesoildue tonitrific…     

硝化抑制剂对我国蔬菜生产产量、氮肥利用率和氧化亚氮减排效应的影响:Meta分析

我国蔬菜生产系统由于长期过量施肥导致氮肥利用率低和环境问题严重,氮肥配施硝化抑制剂是降低活性氮损失、增加蔬菜产量和提高氮肥利用率的有效策略,然而缺乏系统研究.基于数据整合分析的方法,系统分析了氮肥配施硝化抑制剂［双氰胺（DCD）、3,4-二甲基吡唑磷酸盐（DMPP）和2-氯-6-三氯甲基吡啶（NP）］对我国蔬菜生产的产量、植株氮吸收、氮肥利用率和氧化亚氮减排效应的影响,进一步揭示不同田间管理措施对其效果的影响.结果表明,氮肥配施硝化抑制剂能够显著提高蔬菜产量（9.2%）、植株氮吸收（10.4%）和氮肥利用效率（11.2%）,同时减少氧化亚氮排放（28.4%）.不同硝化抑制剂类型中,NP对增产效应和氧化亚氮减排效应的影响幅度最高,分别为16.1%和32.0%,其次是DMPP和DCD.硝化抑制剂在不同氮肥用量中能提高蔬菜产量（6.7%~14.7%）和减少氧化亚氮排放（14.6%~36.8%）.在中性和碱性菜地土壤中,硝化抑制剂的增产效应和氧化亚氮减排效应的影响幅度较酸性土大.硝化抑制剂在露地栽培、根菜类和叶菜类的条件下对产量的增加和氧化亚氮的减排效果较好.主成分分析表明,土壤总氮含量和土壤pH是影响硝化抑制剂对蔬菜产量形成和驱动氧化亚氮排放的主要因素.综上,硝化抑制剂是实现蔬菜系统提质增效、节肥减排的重要举措.同时,农户应根据土壤和田间管理措施选择适宜硝化抑制剂类型,以最大限度提高其有效性.     

菜地氨氧化微生物驱动的N2O和NO对有机无机肥配施的响应

氨氧化细菌（AOB）和氨氧化古菌（AOA）是驱动土壤氨氧化过程的"引擎".氨氧化过程在土壤氧化亚氮（N₂O）和一氧化氮（NO）排放过程中扮演着重要角色.有机无机肥配施是实现化肥零增长和作物稳产增产的重要途径，但在有机无机肥配施下，菜地土壤AOB和AOA对氨氧化过程的相对贡献仍不清楚.本研究采用选择性抑制的方法（辛炔和乙炔）区分有机肥添加近3年后（2016年10月—2019年5月）AOB和AOA在氨氧化过程中对碱性菜地土壤N₂O和NO产生的相对贡献.试验共设5种施肥处理：不施氮肥（CK）、单施尿素（N）、单施有机肥（M）、50%尿素+50%有机肥（M1N1）和80%尿素+20%有机肥（M1N4）.结果表明，有机无机肥配施（M1N1和M1N4）可显著增加土壤电导率、有机碳和全氮含量.培养试验发现，与N处理相比，M和M1N1处理分别使N₂O排放量增加100.7%和38.8%，NO排放量增加77.9%和42.8%，AOB基因丰度增加16.6%和10.2%，同时，AOB对N₂O排放的相对贡献增加6.5%.相反，M1N4处理分别使N₂O和NO排放量降低19.3%和4.8%，AOB基因丰度降低37.5%，同时，AOB对N₂O及NO排放的相对贡献分别降低7.8%和7.4%.相关分析表明，土壤N₂O和NO累积排放量与土壤AOB基因丰度呈显著正相关（p<0.05），与土壤AOA基因丰度无显著相关性.有机无机肥配施下AOB是氨氧化过程的主要驱动者，适当比例的有机无机肥配施（即M1N4）措施可在一定程度上减弱AOB对碱性菜地土壤N₂O及NO排放的相对贡献.     

有机肥与无机肥配施对潮土N2O排放的影响

华北平原是我国重要的粮食主产区,由于土壤有机质含量低,增加氮肥用量并不能导致玉米产量持续增加.有机肥和无机肥配施被广泛认为是同时实现粮食增产和提高土壤有机质的双赢措施,但是有机肥和无机肥配施对华北平原农田N_2O排放的影响尚不明确.本研究在华北平原潮土区,通过测定不同种类有机肥与无机肥配施后农田N_2O排放通量和作物产量,旨在揭示不同种类有机肥及其用量对潮土N_2O排放和作物产量的影响效应.田间试验共设置8个处理,分别为不施肥(CK)、化肥氮(NPK)、 40%牛粪氮+60%化肥氮(CM)、 40%鸡粪氮+60%化肥氮(FC)、 40%猪粪氮+60%化肥氮(FP)、 20%牛粪氮+80%化肥氮(1/2CM)、 20%鸡粪氮+80%化肥氮(1/2FC)和20%猪粪氮+80%化肥氮(1/2FP).整个玉米季N_2O排放通量均与土壤WFPS显著正相关(P0.05).除NPK处理外,玉米季N_2O排放量与土壤可溶性有机碳(DOC)平均含量存在显著的线性关系.玉米季CK处理N_2O排放量为0.50 kg·hm~(-2),NPK处理增加到2.28 kg·hm~(-2).相同用量不同种类有机肥处理,N_2O排放未出现显著差异. 40%有机肥氮用量处理下N_2O排放量与NPK处理无显著差异,而用量减少至20%后, 1/2CM、 1/2FC和1/2FP处理N_2O排放量分别较CM、 FC和FP减少了33.6%、 43.7%和12.1%,其主要原因为易分解有机碳输入减少,土壤DOC含量降低,但玉米产量未出现显著差异.因此,从减少温室效应的角度,玉米季80%化肥氮配施20%有机肥氮为本地区农田施肥的较佳选择.     

Nitrous oxide emissions from a maize field during two consecutive growing seasons in the North China Plain

Nitrous oxide (N₂O) emissions from a maize field in the North China Plain (Wangdu County, Hebei Province, China) were investigated using static chambers during two consecutive maize growing seasons in the 2008 and 2009. The N₂O pulse emissions occurred with duration of about 10 days after basal and additional fertilizer applications in the both years. The average N₂O fluxes from the CK (control plot, without crop, fertilization and irrigation), NP (chemical N fertilizer), SN (wheat straw returning plus chemical N fertilizer), OM- 1/2N (chicken manure plus half chemical N fertilizer) and OMN (chicken manure plus chemical N fertilizer) plots in 2008 were 8.51, 72.1, 76.6, 101, 107 ng N/(m²·sec), respectively, and in 2009 were 33.7, 30.0 and 35.0 ng N/(m²·sec) from CK, NP and SN plots, respectively. The emission factors of the applied fertilizer as N₂O-N (EFs) were 3.8% (2008) and 1.1% (2009) for the NP plot, 3.2% (2008) and 1.2% (2009) for the SN plot, and 2.8% and 2.2% in 2008 for the OM-1/2N and OMN plots, respectively. Hydromorphic properties of the investigated soil (with gley) are in favor of denitrification. The large differences of the soil temperature and water-filled pore space (WFPS) between the two maize seasons were suspected to be responsible for the significant yearly variations. Compared with the treatments of NP and SN, chicken manure coupled with compound fertilizer application significantly reduced fertilizer loss rate as N₂O-N.     

添加不同 N源条件下典型除草剂对土壤呼吸和 N2O排放的影响

通过室内土壤培养实验,采用间歇密闭培养-气相色谱法研究了添加不同N源条件下我国典型旱地除草剂对农田土壤呼吸和N2O排放的影响.结果表明,在添加（NH4）2SO4氮源条件下,莠去津和百草枯对土壤呼吸和N2O排放无显著影响（P〉0.05）.草甘膦显著抑制了土壤呼吸（P〈0.05）,是对照的78.5%,N2O的排放无显著影响（P〉0.05）,仅表现为均值降低了20.1%.苯磺隆显著促进了土壤呼吸（P〈0.05）,是对照的1.1倍,对N2O排放也无显著影响（P〉0.05）.乙草胺显著促进了土壤呼吸和N2O的排放（P〈0.05）,分别是对照的1.1和1.5倍.在添加尿素的条件下,莠去津和乙草胺对土壤呼吸和N2O排放无显著影响（P〉0.05）.百草枯显著促进了N2O的排放（P〈0.05）,是对照的1.4倍,却对土壤呼吸无显著影响（P〉0.05）.草甘膦显著抑制了土壤呼吸（P〈0.05）,仅为对照的82.5%,对N2O的排放却无显著影响（P〉0.05）.苯磺隆显著促进了土壤呼吸和N2O的排放（P〈0.05）,其分别是对照的1.3和1.6倍.鉴于不同除草剂对不同微生物生理代谢影响的复杂性,其对温室气体的作用和影响还需长期田间试验研究.     

N2O emissions from agricultural soils in the North China Plain:the effect of chemical nitrogen fertilizer and organic manure

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Effects of a new nitrification inhibitor 3,4-dimethylpyrazole phosphate （DMPP） on nitrate and potassium leaching in two soils

In this study, soil column was used to study the new nitrification inhibitor 3,4-dimethylpyrazole phosphate （DMPP） on nitrate （NO3^-- N） and potassium （K） leaching in the sandy loam soil and clay loam soil. The results showed that DMPP with ammonium sulphate nitrate （ASN） （（NH4）2SO4 and NHaNO3） or urea could reduce NO3^--N leaching significantly, whereas ammonium （NH4^＋-N） leaching increased slightly. In case of total N （NO3^--N＋NH4^＋-N）, losses by leaching during the experimental period （40 d） were 37.93 mg （urea）, 31.61 mg （urea＋DMPP）, 108.10 mg （ASN）, 60.70 mg （ASN＋DMPP） in the sandy loam soil, and 30.54 mg （urea）, 21.05 mg （urea＋DMPP）, 37.86 mg （ASN）, 31.09 mg （ASN＋DMPP） in the clay loam soil, respectively. DMPP-amended soil led to the maintenance of relatively high levels of NH4^＋ -N and low levels of NO3^--N in soil, and nitrification was slower. DMPP supplementation also resulted in less potassium leached, but the difference was not significant except the treatment of ASN and ASN＋DMPP in the sandy loam soil. Above results indicate that DMPP is a good nitrification inhibitor, the efficiency of DMPP seems better in the sandy loam soil than in the clay loam soil and lasts longer.     

Managing the nitrogen cycle to reduce greenhouse gas emissions from crop production and biofuel expansion

Public policies are promoting biofuels as an alternative to fossil fuel consumption in order to mitigate greenhouse gas (GHG) emissions. However, the mitigation benefit can be at least partially compromised by emissions occurring during feedstock production. One of the key sources of GHG emissions from biofuel feedstock production, as well as conventional crops, is soil nitrous oxide (N₂O), which is largely driven by nitrogen (N) management. Our objective was to determine how much GHG emissions could be reduced by encouraging alternative N management practices through application of nitrification inhibitors and a cap on N fertilization. We used the US Renewable Fuel Standards (RFS2) as the basis for a case study to evaluate technical and economic drivers influencing the N management mitigation strategies. We estimated soil N₂O emissions using the DayCent ecosystem model and applied the US Forest and Agricultural Sector Optimization Model with Greenhouse Gases (FASOMGHG) to project GHG emissions for the agricultural sector, as influenced by biofuel scenarios and N management options. Relative to the current RSF2 policy with no N management interventions, results show decreases in N₂O emissions ranging from 3 to 4 % for the agricultural sector (5.5–6.5 million metric tonnes CO₂?eq.?year^?1; 1 million metric tonnes is equivalent to a Teragram) in response to a cap that reduces N fertilizer application and even larger reductions with application of nitrification inhibitors, ranging from 9 to 10 % (15.5–16.6 million tonnes CO₂?eq.?year^?1). The results demonstrate that climate and energy policies promoting biofuel production could consider options to manage the N cycle with alternative fertilization practices for the agricultural sector and likely enhance the mitigation of GHG emissions associated with biofuels.     

不同施肥方式下紫色土N2O与NOx的排放特征

利用紫色土长期施肥试验平台,采用静态箱-气相色谱法开展紫色土"冬小麦-夏玉米"轮作系统N_2O和NO_x排放的连续两周年(2014年11月~2016年9月)定位观测.研究了氮肥总量相同条件下的常规氮磷钾化肥(NPK)、猪厩肥(OM)、秸秆还田配施氮磷钾化肥(RSDNPK)、猪厩肥配施氮磷钾化肥(OMNPK)和氮磷钾化肥配合硝化抑制剂(DCDNPK)等施肥方式对N_2O和NO_x排放的影响,短期不施肥处理(CK)作为排放系数计算的对照.结果表明,所有施肥方式下紫色土N_2O排放峰均出现在施肥初期和大降雨过程期;NO_x排放过程与N_2O类似,排放峰出现在施肥初期,但强降雨期未出现明显排放峰.NPK、OM、RSDNPK、OMNPK和DCDNPK处理的N_2O年均累积排放量分别为:1.35、4.38、1.43、2.46、0.92 kg·hm~(-2),排放系数分别为:0.33%、1.41%、0.36%、0.73%、0.18%;相应处理的NO_x年均累积排放量分别为:0.11、0.38、0.10、0.27、0.04kg·hm~(-2),排放系数分别为:0.03%、0.13%、0.03%、0.09%、0.01%.较常规化肥,增加有机物料如施用猪厩肥和猪厩肥配施氮磷钾肥分别显著增加226%和83%的N_2O排放(P0.01),同时NO_x排放分别显著增加262%和157%(P0.01);常规化肥配合硝化抑制剂(DCDNPK)使用减少32%的N_2O排放和62%的NO_x排放(P0.01),秸秆还田配施氮磷钾肥对N_2O排放略有增加(P0.05),NO_x排放略有减少(P0.05).统计分析进一步表明,土壤无机氮含量是N_2O和NO_x二者排放的主控因子,而土壤孔隙充水率与温度分别作为N_2O与NO_x各自排放的主控因子之一.     

Effects of the new nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on nitrate and potassium leaching in two soils

In this study, soil column was used to study the new nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on nitrate (NO3--N) and potassium (K) leaching in the sandy loam soil and clay loam soil. The results showed that DMPP with ammonium sulphate nitrate (ASN) ((NH4)2SO4 and NH4NO3) or urea could reduce NO3--N leaching significantly, whereas ammonium (NH4 -N) leaching increased slightly. In case of total N (NO3--N NH4 -N), losses by leaching during the experimental period (40 d) were 37.93 mg (urea), 31.61 mg (urea DMPP), 108.10 mg (ASN), 60.70 mg (ASN DMPP) in the sandy loam soil, and 30.54 mg (urea), 21.05 mg (urea DMPP), 37.86 mg (ASN), 31. 09 mg (ASN DMPP) in the clay loam soil, respectively. DMPP-amended soil led to the maintenance of relatively high levels of NH4 -N and low levels of NO3--N in soil, and nitrification was slower. DMPP supplementation also resulted in potassium leached less, but the difference was not significant except the treatment ASN and ASN DMPP in the sandy loam soil. Above results indicate that DMPP is a good nitrification inhibitor, the efficiency of DMPP seems better in the sandy loam soil than in the clay loam soil and lasts longer.     

氮肥和磷肥对稻田N2O排放的影响

通过模拟南方稻田施用不同量的氮肥和磷肥的实验来探讨N和P对稻田释放N2O的影响.结果表明,水稻田N2O排放通量的较大值主要出现在3次烤田期;氮肥和磷肥对土壤中产生N2O的贡献主要在水稻生长中后期,从第1次烤田起(移栽后34d),氮肥和磷肥都表现为对N2O排放有促进作用;而低氮对N2O排放的刺激作用没有高氮的作用明显,且N2处理(180kg/hm2)、N1处理(90kg/hm2)和N0处理(没有施肥)之间的平均N2O排放差异不显著.在水稻生长中后期(第1次烤田后),N3处理(270kg/hm2)和N4处理(360kg/hm2)的较高水平的氮肥加入能强烈刺激N2O排放.     

Effects of long-term amendment of organic manure and nitrogen fertilizer on nitrous oxide emission in a sandy loam soil

To understand the effects of long-term amendment of organic manure and N fertilizer on N2O emission in the North China Plain, a laboratory incubation at different temperatures and soil moistures were carried out using soils treated with organic manure （OM）, half organic manure plus half fertilizer N （HOM）, fertilizer NPK （NPK）, fertilizer NP （NP）, fertilizer NK （NK）, fertilizer PK （NK） and control （CK） since 1989. Cumulative N2O emission in OM soil during the 17 d incubation period was slightly higher than in NPK soil under optimum nitrification conditions （25℃ and 60% water-filled pore space, WFPS）, but more than twice under the optimum denitrification conditions （35℃ and 90% WFPS）. N2O produced by denitrification was 2.1-2.3 times greater than that by nitrification in OM and HOM soils, but only 1.5 times greater in NPK and NP soils. These results implied that the long-term amendment of organic manure could significantly increase the N2O emission via denitrification in OM soil as compared to NPK soil. This is quite different from field measurement between OM soil and NPK soil. Substantial inhibition of the formation of anaerobic environment for denitrification in field might result in no marked difference in N2O emission between OM and NPK soils. This is due in part to more rapid oxygen diffusion in coarse textured soils than consumption by aerobic microbes until WFPS was 75% and to low easily decomposed organic C of organic manure. This finding suggested that addition of organic manure in the tested sandy loam might be a good management option since it seldom caused a burst of N2O emission but sequestered atmospheric C and maintained efficiently applied N in soil.     

黄河口典型潮滩湿地土壤净氮矿化与硝化作用

采用PVC顶盖埋管原位培育法研究了黄河口典型潮滩湿地土壤净氮矿化与净硝化作用的动态变化特征、影响因素及净氮矿化/硝化量.结果表明,高潮滩湿地(LW)、中潮滩湿地(JP1)和低潮滩湿地(JP2)0~15cm土壤无机氮含量具有明显的季节变化特征,NH4+-N含量表现为LW＞JP1＞JP2,NO3--N含量则表现为JP1＞LW＞JP2.3种湿地土壤净氮矿化/硝化速率均呈明显的波动变化.生长季的净氮矿化量分别为27.81、11.90和0.33kg/hm2,净硝化量分别为12.09、15.99和1.19kg/hm2,净硝化量占净氮矿化量的百分比分别为43.47%、100.00%和100.00%.相关分析表明,湿地土壤净氮矿化量与土壤水分含量呈显著负相关,而土壤净氮硝化量与土壤pH值呈显著负相关.3种潮滩湿地土壤在维持无机氮方面的能力整体表现为LW＞JP1＞JP2,说明从氮循环角度高潮滩湿地系统最为稳定,而低潮滩湿地系统的稳定性最差.     

不同施肥方式对设施土壤氨挥发特征的影响

有机肥与改良剂施入土壤是改善土壤结构、增加土壤有机质含量和培肥地力的重要措施,但也会影响土壤的氨挥发,探索不同施肥方式对土壤氨挥发的影响,对于减少氮素损失和保护生态环境具有重要意义.基于设施番茄微区试验,采用LGR915-0016超便携NH₃分析仪观测不同施肥方式[50%化肥N+50%有机肥N+改良剂组（HYG）、50%化肥N+50%有机肥N组（HY）、100%有机肥N组（Y）、100%化肥N组（H）和不施肥处理组（CK）]下土壤氨的排放特征.结果表明:在番茄生育期内,不同施肥方式下设施土壤氨挥发通量的变化趋势基本一致.在土壤氨累积挥发量方面,与CK处理相比,H和HY处理下土壤中氨累积挥发量分别增加了11.76%和12.03%;Y和HYG处理则显著降低了土壤中氨累积挥发量,分别下降了24.31%和15.20%.就单因素模型而言,不同施肥处理下土壤氨挥发通量与0~10 cm土壤温度呈线性回归关系,且各处理均达到显著水平（P均小于0.05）;不同施肥处理下土壤氨挥发通量与0~10 cm土壤含水量均呈显著二次回归关系（P均小于0.05）;与单因素相比,0~10 cm土壤含水量和土壤温度的双因素复合模型（R2为0.700 6~0.849 7）可以更好地解释土壤氨挥发通量的变化情况.相关分析显示,土壤氨累积挥发量与0~20 cm土层土壤铵态氮含量、硝态氮含量、pH及土壤孔隙度均呈极显著相关（P均小于0.01）,与0~20 cm土层土壤容重呈显著相关（P < 0.05）.采用PCA分析提取的2个主成分的累积贡献率为83.09%.研究显示,不同施肥方式会影响设施土壤氨挥发通量,综合考虑土壤氨累积挥发量及其影响因素,100%有机肥N组在降低土壤氨挥发方面显著优于其他处理组.      

不同有机物料对土壤N2O排放的影响与调控

通过向土壤施加15N标记的莴笋残体(处理R)、废纸浆(处理P)及二者混合物(处理RP),并利用不同的压力使其成为3种不同容重处理的土壤样本,进行密闭培养,定时测定土壤N2O排放量及土壤溶液中NO3-与NH4 的动态变化,以探讨N_2O的产生与调控机制.结果表明,8d N2O释放量为R处理最大,RP处理其次,P处理最小.短期内(8d)R处理N2O释放最大量为空白对照(CK)的15倍,增加了土壤反硝化作用;P处理在同期内不能增加N2O释放量,证明这种废纸浆可少量(<2.5%)施用于农田中.RP与CK、P处理比较,可以刺激微生物活性和增加土壤反硝化作用;与R处理相比较,可以增加氮的固定.增加有机质的添加量使同一容重水平的RP处理N2O释放量高于R处理.70%的土壤样本随容重增加N2O释放量增加.土壤容重的增加同时影响了废纸浆的分解速率和土壤溶液中NO3-与NH4 浓度.     

不同灌溉方式旱田土壤N2O排放和氮素淋溶特征

通过野外原位监测试验,利用静态箱-气相色谱法、土壤溶液提取器分别对旱田土壤N₂O排放及氮素淋溶进行2018和2019年连续两年观测.试验设计为DCK （滴灌无肥）、DD （滴灌+N 500kg/hm²）、DG （滴灌+N 1000kg/hm²）、FCK （沟灌无肥）、FD （沟灌+N 500kg/hm²）、FG （沟灌+N 1000kg/hm²）.结果表明,不同施氮量、不同灌溉方式对N₂O排放和氮素淋溶量影响具有极显著差异（P<0.01）.N₂O排放量随施氮量的增加而增加,滴灌与沟灌相比可有效降低N₂O排放,2018和2019年FCK、FD、FG的N₂O累积排放量分别为2,23.79,45.73kg/hm²和2.08,6.23,13.93kg/hm²,而DCK、DD、DG分别降低了35%、80.9%、75.6%和26.7%、66.4%、21.5%.2018和2019年旱田土壤氮素淋溶量均表现为：滴灌<沟灌,80cm深度土壤溶液氮素淋溶量<40cm.2018和2019年相同施氮量下滴灌与沟灌相比,在40cm和80cm分别能减少氮素淋溶量36.95%~63.10%和54.93%~87.92%.主成分分析结果表明,影响N₂O排放的主要环境因子为土壤NO₃^--N含量和降水频率,相关系数分别为0.689、0.596;影响氮素淋溶量的主要环境因子为降水频率和灌水频率,相关系数分别为0.697和-0.729.滴灌可有效减少N₂O排放和氮素淋溶量,在提高肥料利用率的同时可减轻环境污染.     

Nitrous oxide fluxes from upland soils in central Hokkaido, Japan

Nitrous oxide (N2O) fluxes from soils were measured using the closed chamber method during the snow-free seasons (middle April to early November),for three years,in a total of 11 upland crop fields in central Hokkaido,Japan.The annual mean N2O fluxes ranged from 2.95 to 164.17 μgN/(m2·h),with the lowest observed in a grassland and the highest in an onion field.The instantaneous N2O fluxes showed a large temporal variation with peak emissions generally occurring following fertilization and heavy rainfall eve...