IMHE OpenIR  > 山地表生过程与生态调控重点实验室
施肥方式对紫色土活性氮污染物迁移的影响
Alternative TitleEffects of Fertilization Regimes on the Movements of Reactive Nitrogen from Purple Soil
Language中文
胡廷旭
Thesis Advisor朱波
2015
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Name硕士
Degree Discipline土壤学
Keyword氮氧化物排放 氮流失 施肥方式 紫色土
Abstract氮是农作物生长发育的最重要的养分元素,氮肥施用是粮食稳产、增产的最重要的措施。但过量施用氮肥也会导致严重的环境问题,土壤氮氧化物排放和氮流失是农田活性氮污染的两个重要过程,前者影响大气中温室气体浓度,可能加剧大气温室效应,后者是农田面源污染的核心问题,对水环境造成重要影响。紫色土是中国西南地区最重要的农耕土壤,是保障当地粮食安全的重要耕地资源,同时紫色土位于长江上游,对长江水环境有重要影响,而紫色土活性氮污染物的迁移过程、特征及其施肥的影响还有待深入。本研究以紫色土坡耕地农田生态系统为研究对象,依托中国科学院盐亭紫色土农业生态试验站,利用可同步观测氮氧化物排放和氮素径流迁移的大型自由排水采集器(Free-drain-lysimeter),研究紫色土坡耕地夏玉米-冬小麦轮作系统的氮氧化物排放与氮流失过程与通量,比较了化肥(N、NPK)、有机肥(OM)、无机-有机肥配施(OMNPK)、秸秆还田与化肥配施(RSDNPK)、化肥及硝化抑制剂(DCDNPK)、化肥添加生物炭(BCNPK)及不施肥对照(CK)对紫色土氮氧化物排放与氮流失的影响,并结合作物产量、活性氮污染负荷减排进行综合效应评估,筛选紫色土坡耕地氮氧化物排放和氮流失协同减排的优化施肥方式。主要研究结果和结论如下: (1)施肥方式对紫色土旱地氮氧化物排放的影响 施肥促发紫色土N2O和NO排放。常规NPK施肥处理小麦季和玉米季的N2O排放峰值和通量分别为94±10 μg(N)?m-2?h-1、0.42±0.16 kg(N)?hm-2,211±56 μg(N)?m-2?h-1、0.53±0.02 kg(N)?hm-2。NO的排放峰值和通量分别为83±12 μg(N)?m-2?h-1、0.25±0.05 kg(N)?hm-2,33±3 μg(N)?m-2?h-1、0.14±0.03 kg(N)?hm-2。与常规NPK施肥方式相比,有机肥施用既提前了N2O排放出峰时间,又增加了峰值的排放速率,导致紫色土小麦-玉米轮作周期的N2O累积排放增加,小麦季和玉米季相对于常规NPK施肥分别高出3.3和7.3倍,分别达到1.41和3.89 kg(N)?hm-2。有机肥在冬小麦季具有最低的NO累积排放通量,在夏玉米季却具有最高的NO累积排放通量,这可能是因为土壤水分条件影响所致。常规化肥(NPK)基础上施用硝化抑制剂(DCDNPK)则显著降低了N2O和NO的排放通量,相比于常规NPK施肥处理分别减少了27%和66%。RSDNPK相比于常规NPK施肥的N2O累积排放增加,冬小麦季和夏玉米季分别增加了24%和68%。但是NO显著小于常规NPK施肥,冬小麦季和夏玉米季分别减少了56%和57%。BCNPK施肥处理相比于常规NPK施肥对于氮氧化物的排放影响不明显。 (2)施肥方式对土壤排放氮氧化物比值的影响 施肥对NO/N2O具有促发作用。常规NPK施肥施肥后均表现出较高的NO/N2O,在冬小麦季NO/N2O最高值达到2,在夏玉米季NO/N2O最高值达到0.9。单施氮肥和BCNPK施肥处理也在施肥后具有较高的NO/N2O。而有机肥施肥处理(OM)、有机肥配施氮磷钾施肥处理(OMNPK)和秸秆还田配施氮磷钾施肥处理(RSDNPK)相对于常规NPK施肥处理具有较低的NO/N2O。降雨事件会降低NO/N2O,导致NO/N2O排放出现多峰现象。干旱条件会激发NO/N2O峰值的出现,持久的干旱影响到土壤微生物的活性从而会降低NO/N2O。 (3)施肥方式对紫色土坡耕地径流与泥沙的影响 施肥方式对紫色土地表径流和壤中流流量及泥沙损失有显著影响。 常规NPK施肥在实验期间总产地表径流31.2 mm,单施氮肥和空白对照及有机无机混施施肥处理相比于其他施肥处理具有显著较高的地表径流量;OM施肥处理和RSDNPK施肥处理相比于其他施肥处理具有显著较低的地表径流量;BCNPK施肥处理和DCDNPK施肥处理对于地表径流产流的影响相对于常规NPK施肥不显著。 常规NPK施肥在实验期间总产壤中流176.3 mm。OM施肥处理具有最高壤中流径流量,RSDNPK施肥处理都具有最小的土壤壤中流径流量,其他施肥处理壤中流径流量差异不显著。 常规NPK施肥在实验期间泥沙损失量为446 kg?hm-2。单施氮肥处理和空白对照处理泥沙损失显著高于常规NPK施肥处理,分别达到671 kg?hm-2和890 kg?hm-2。RSDNPK施肥处理相对常规NPK施肥处理具有显著低的泥沙损失量,仅68 kg?hm-2,表明RSDNPK具有较强的保水、保土功能;OM、OMNPK和DCDNPK相比于常规NPK施肥均具有较少的泥沙损失量,年度泥沙损失约为300 kg?hm-2;BCNPK施肥处理泥沙损失量与常规NPK施肥相比不显著。 (4)施肥方式对紫色土坡耕地氮素径流损失的影响。 紫色土氮素径流损失主要有地表径流和壤中流两种径流形式,径流损失中的氮主要由铵态氮、硝态氮和颗粒态氮构成。施肥方式对紫色土氮素流失特征具有显著影响。NPK施肥处理全年地表径流损失总氮通量为107 mg?m-2,其中铵态氮3 mg?m-2,硝态氮40 mg?m-2,颗粒态氮65 mg?m-2。壤中流损失总氮通量为4851 mg?m-2,其中铵态氮35 mg?m-2,硝态氮4311 mg?m-2,颗粒态氮506 mg?m-2。全年总损失氮量为49.58 kg?hm-2,占全年施氮量的17.7%。单施氮肥非平衡施肥处理具有显著高的氮素径流损失通量,全年地表径流损失总氮通量为163 mg?m-2,其中铵态氮8 mg?m-2,硝态氮61 mg?m-2,颗粒态氮93 mg?m-2。壤中流损失总氮通量为14524 mg?m-2,其中铵态氮28 mg?m-2,硝态氮12949 mg?m-2,颗粒态氮1548 mg?m-2。全年总损失氮量为146.87 kg?hm-2,占全年施氮量的52.5%。RSDNPK施肥处理具有显著低的氮素径流损失通量,全年地表径流损失总氮通量为63 mg?m-2,其中铵态氮3 mg?m-2,硝态氮34 mg?m-2,颗粒态氮26 mg?m-2。壤中流损失总氮通量为1680 mg?m-2,其中铵态氮16 mg?m-2,硝态氮1552 mg?m-2,颗粒态氮113 mg?m-2。全年总损失氮量为17.43 kg?hm-2,占全年施氮量的6.2%。有机肥OM施肥处理全年损失氮量占全年施氮量的7.3%。有机肥无机肥混施OMNPK施肥处理全年损失氮量占全年施氮量的13.2%。生物炭配施氮磷钾施肥(BCNPK)施肥处理全年损失氮量占全年施氮量的19.6%。硝化抑制剂配施氮磷钾施肥(DCDNPK)施肥处理全年损失氮量占全年施氮量的22.3%。 (5)紫色土活性氮损失的主要环境影响因子 各施肥处理的氮氧化物排放与土壤底物活性氮含量显著正相关。土壤活性氮底物同样是氮素径流损失的源,径流损失的活性氮越多,土壤底物活性氮减少越多,两者呈现负相关性。 土壤氮氧化物排放与土壤温度和土壤湿度之间具有线性相关响应,降雨会激发土壤N2O的排放,但对NO的影响不明显。土壤氮素径流损失通量同样受到环境因素的制约,降雨量和径流量对紫色土各施肥处理的氮素径流损失量均具有显著的相关关系。 (6)控制紫色土活性氮损失的氮肥资源优化管理方式 基于粮食增产稳产条件下对于土壤活性氮污染负荷进行评估。结果显示,RSDNPK施肥处理不论在冬小麦季还是在夏玉米季基于作物单产指标均具有最低的土壤活性氮素损失量,且泥沙损失也显著低于其他几种施肥方式,因此,可以作为本区的最优施肥模式进行推广。
Other AbstractNitrogen is the most important essential elements for agricultural crop. Application of nitrogen fertilizer is the basis for food production and maintenance. However, excessive application of nitrogen fertilizer has resulted in serious environmental problems such as global warming and water eutrophication. Emissions of nitrogen oxides and nitrogen runoff from soil are two important processes of reactive nitrogen pollution induced by agricultural activities, Emission of nitrogen oxides emissions has important effects on greenhouse gases concentration of atmospheric. Nitrogen runoff loss is the main concern of agricultural non-point-source pollution. In this study, in situ field monitoring for both gas emissions of nitrogen oxides and diffuse nitrogen loss via overland flow , interflow and soil erosion has been conducted for a round-year under rotation of wheat-maize in hillslope cropland of purple soil by free-drain lysimeters at Yanting Agro-ecological Experimental Station of Purple Soil, Chinese Academy of Sciences. Meanwhile, fertilization regimes involved in conventional synthetic N, P, K fertilizer (NPK), pig manure (OM), pig manure with synthetic NPK fertilizer (OMNPK), crop residues returned with synthetic NPK fertilizer (RSDNPK),nitrification inhibitors(dicyandiamide) with synthetic NPK fertilizer (DCDNPK) , biochar with synthetic NPK fertilizer (BCNPK) , pure synthetic N fertilizer (N),and no fertilizer (NF) were compared to understand the effects of N fertilization regimes on gas emissions of nitrogen oxides and diffuse nitrogen loss. Based on the comparisons of nitrogen loss and crop yield, optimal N fertilizer management practices for simultaneous mitigation of both nitrogen gas emissions and diffuse N loss from slope cropland of purple soil will be recommended. The results and conclusions were listed as follows: (1) Fertilization regimes had great effects on N2O and NO emissions from purple soil Fertilization regimes had a priming effect on the N2O and NO emissions from purple soil. The peak value and average emission flux of N2O in NPK treatment in wheat and maize season was 94 ±10 μg(N)?m-2?h-1,0.42±0.16 kg(N)?hm-2 and 211±56 μg (N)?m-2?h-1,0.53±0.02 kg(N)?hm-2 respectively. The peak value and emission flux of NO in NPK treatment in wheat and maize season was 83±12 μg.(N)?m-2?h-1,0.25±0.05 kg(N)?hm-2 and 33±3 μg.(N)?m-2?h-1,0.14±0.03 kg(N)?hm-2 respectively. OM had earlier and higher N2O emission peak with higher N2O emission flux compared with inorganic fertilizer treatments. OM had the highest NO emission flux in wheat season, whereas, the lowest emission flux observed in maize season. DCDNPK decreased both N2O and NO emission flux than other treatments. RSDNPK increased N2O emission whereas decreases NO emission compared with NPK treatment. BCNPK had no significant effect on NOX flux compared with NPK treatment. (2) Effects of fertilization regimes on NO/N2O Fertilization regimes had promoting effect on NO/N2O. NPK treatment had high NO/N2O after fertilization, the highest value was 2 in wheat season which was 0.9 in maize season. N and BCNPK treatments also had higher NO/N2O in both maize and wheat seasons after fertilization. OM and RSDNPK treatment had lower NO/N2O. Rain would reduce NO/N2O, whereas, drought would enhance NO/N2O. But extreme drought will also reduce NO/N2O. The results indicated that the soil moisture has significant influence on soil nitrification. (3) Effects of fertilization on runoff and sediment yield in purple soil NPK treatment had annual discharge of overland flow with 31.2 mm in the experiment period. N and CK treatments had more overland flow discharges than other treatments. OM and RSDNPK had significant lower overland flow discharges compared with other treatments. BCNPK and DCDNPK treatments had no significant different discharge of overland flow compared with NPK. NPK treatment had annual interflow discharge with 176.3 mm in the experiment period. OM treatment had maximum interflow discharge, whereas, RSDNPK treatment had the lowest interflow discharge. NPK treatment had annual sediment yield of 446 kg?hm-2 in the experiment period. Sediment yields from N and CK treatments were 671 kg?hm-2 and 890 kg?hm-2 respectively. They had more sediment yield than other treatments. OM, OMNPK, DCDNPK and RSDNPK treatments had significantly lower sediment yield compared with NPK treatment. RSDNPK treatment had the lowest sediment yield as 68 kg?hm-2. BCNPK had no significant different sediment yield from NPK treatment. (4) Effects of fertilization regimes on diffuse nitrogen loss in purple soil Nitrogen transports via overland flow, interflow and soil erosion. The loss flux of nitrogen via overland flow of NPK treatment was 107 mg?m-2, which included NH4+-N in 3 mg?m-2, NO3--N in 40 mg?m-2, and particulate-N (PN) in 65 mg?m-2. The loss flux of nitrogen via interflow of NPK treatment was 4851 mg?m-2, which included NH4+-N in 35 mg?m-2, NO3--N in 4311 mg?m-2, and PN in 506 mg?m-2. The loss flux of total nitrogen was 49.58 kg?hm-2 of NPK treatment, which accounted for 17.7% of annual nitrogen applied. N treatment had significant higher loss flux of nitrogen than other treatments. The loss flux of nitrogen from N treatment via overland flow of N treatment was 163 mg?m-2, which included NH4+-N in 8 mg?m-2, NO3—N in 61 mg?m-2, PN in 93 mg?m-2. The loss flux of nitrogen via interflow from N treatment was 14524 mg?m-2, which include NH4+-N in 28 mg?m-2, NO3--N in 12949 mg?m-2,PN in 1548 mg?m-2. The total nitrogen loss flux was 146.8 kg?hm-2 from N treatment, which accountd for 52.5% of annual nitrogen applied. RSDNPK treatment had significant lower loss flux of than other treatments. The loss flux of nitrogen from RSDNPK treatment via overland flow was 63 mg?m-2, which included NH4+-N in 3 mg?m-2, NO3--N in 34 mg?m-2, PN in 26 mg?m-2. The loss flux of nitrogen via interflow from RSDNPK treatment was 1680 mg?m-2, which included NH4+-N in 16 mg?m-2, NO3--N in 1552 mg?m-2, PN in 113 mg?m-2. The total nitrogen loss flux was 17.4 kg?hm-2 from RSDNPK treatment, which accountd for 6.2% of annual nitrogen applied. The total nitrogen loss flux via runoff of OM treatment accountd for 7.3% of annual nitrogen applied. The total nitrogen loss flux via runoff of OMNPK treatment accountd for 13.2% of annual nitrogen applied. The total nitrogen loss flux via runoff of BCNPK treatment accountd for 19.6% of annual nitrogen applied. The total nitrogen loss flux via runoff of DCDNPK treatment accountd for 22.3% of annual nitrogen applied. (5) The main impacting factors on reactive nitrogen loss There was obvious correlation between NOX flux and soil nitrogen content. Soil nitrogen is also the source substrate of diffuse nitrogen loss. When runoff happened, soil nitrogen would definitely decrease. There were linear relations with NOX fluxes between soil temperatures and soil moistures. Rain would promote N2O emission, whereas it had no obvious effect on NO emission. The precipitation and runoff discharge had linear relations with diffuse nitrogen loss flux. (6) In order to maintain crop yield and reduce the reactive notrogen loss as much as possible, comprehensive effects of different fertilization regimes had been estimated through crop yields, nitrogen loss loadings and economic gains. The fertilization regime of RSDNPK with high crop yield had the lowest nitrogen and sediment loss. So, we recommended RSDNPK as the optimal fertilization mode in the hilly area of purple soil.
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/14130
Collection山地表生过程与生态调控重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
胡廷旭. 施肥方式对紫色土活性氮污染物迁移的影响[D]. 北京. 中国科学院大学,2015.
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