共查询到17条相似文献,搜索用时 234 毫秒
1.
为揭示亚热带森林土壤N2O排放对林分类型和氮添加的响应特征,选取位于福建省三明市的中亚热带米槠次生林、杉木人工林和马尾松人工林土壤为研究对象,分别设置无氮添加(N0 mg/kg)、低氮添加(N10 mg/kg)、中氮添加(N25 mg/kg)和高氮添加(N50 mg/kg)4个氮添加水平,进行微宇宙培养试验,测定土壤N2O排放。结果表明:与无氮添加处理相比,氮添加整体上降低3种林分土壤pH,增加土壤NH4+-N和NO3--N含量。无氮添加处理中杉木人工林和马尾松人工林土壤N2O累积排放量分别为9.67和9.62 mg/kg,显著高于米槠次生林土壤N2O累积排放量6.81 mg/kg。低氮添加处理中杉木人工林和马尾松人工林土壤N2O累积排放量显著高于米槠次生林。但在中氮和高氮添加处理中,3种林分土壤N2O累积排放量均无显著性差异。不同氮添加处理均促进3种林分土壤N 相似文献
2.
3.
4.
减氮和施生物炭对华北夏玉米-冬小麦田土壤CO2和N2O 排放的影响 总被引:1,自引:0,他引:1
2013年6月-2014年6月,在河南省新乡夏玉米-冬小麦试验田设置四种处理即农民常规施肥(F处理,250kg·hm-2)、减氮20%(LF处理,200kg·hm-2)、减氮20%+黑炭(LFC),以不施肥处理为对照(CK),采用静态箱-气相色谱法,对夏玉米-冬小麦生长季土壤CO2和N2O排放通量动态进行测定。结果表明:(1)夏玉米-冬小麦田的土壤CO2排放通量为21.8~1022.7mg·m-2·h-1,土壤CO2排放通量主要受土壤温度和水分的影响,在夏玉米季受土壤水分的影响更为显著,而在冬小麦季则为5cm土层处的温度对其影响更为突出。减施氮肥20%处理和减氮加生物黑炭共同作用使土壤CO2累积排放量显著降低,小麦生长季的减排作用尤为显著。(2)施肥和灌溉是影响土壤N2O排放的最主要因素,施肥期间N2O排放量分别占夏玉米季和冬小麦季累积排放量的73.9%~74.5%和40.5%~43.6%;施肥量主要影响排放峰的强度,灌溉主要影响排放峰出现时间的早晚且会影响不同措施的减排效果。在每季作物250kg·hm-2施氮水平下减施氮肥20%使夏玉米季和冬小麦季的N2O累积排放量分别降低15.7%~16.8%和18.1%~18.5%,是高产集约化农田减排N2O的有效措施。在适宜施氮水平(200kg·hm-2)下施用生物黑炭,短期内对土壤N2O排放无显著影响。(3)夏玉米-冬小麦田农民常规施肥水平的N2O排放系数为0.60%,减氮施肥的N2O排放系数为0.56%。在华北平原高产集约化农田适当减氮施肥不仅能降低农田土壤温室气体排放,且对作物产量无影响,是适宜的温室气体减排措施。 相似文献
5.
不同形态氮添加对毛竹林土壤N2O排放的影响 总被引:2,自引:1,他引:1
6.
添加秸秆及其生物质炭对淹水条件下砖红壤N2O和CH4排放的影响 总被引:1,自引:1,他引:0
为探讨添加秸秆及其生物质炭对淹水条件下砖红壤N2O和CH4排放的影响,以海南砖红壤为供试土壤,设置了玉米秸秆(Straw)、生物质炭(Biochar)、秸秆 + 生物质炭(Mix)和对照(CK)4个处理,探讨了等秸秆用量条件下添加不同秸秆形态对土壤氧化亚氮(N2O)和甲烷(CH4)排放的影响及形成强还原环境的可行性。结果表明:与CK处理相比,三个处理均可显著降低土壤N2O累计排放量,但仅Straw处理可显著促进土壤CH4排放、其它两个处理对土壤CH4排放影响不显著,致使straw处理综合温室效应增加明显。与CK处理相比,与Mix处理5天内土壤氧化还原电位(Eh)显著下降,而Biochar处理土壤Eh变化不显著;三个处理均使土壤pH上升、但Straw与Biochar处理之间差异不显著,Mix处理土壤有机碳、全氮及速效钾含量显著增加。因此,玉米秸秆及其生物质炭的配合施用,既可有效降低淹水条件下海南砖红壤排放CH4和N2O的综合温室效应,还能改善土壤养分状况但易于形成强还原条件。 相似文献
7.
不同配比有机无机肥料对菜地N2O排放的影响 总被引:3,自引:1,他引:2
8.
全球环境变化一直是人们广泛关注的热点问题,由人类活动和化石燃料燃烧引起的温度持续升高、温室气体排放增加、极端天气频繁发生等现象对土壤理化性质及微生物活动产生深刻影响。N2O作为一种具有强增温潜势的温室气体,对生态环境造成极大威胁。因此,全面深入地探究全球变化下不同环境因子对土壤N2O排放的影响有重要意义。论文综述了模拟全球变暖、CO2浓度倍增、降水格局改变以及氮沉降对土壤N2O排放的影响及微生物作用机制,阐述不同变化因子对N2O排放的交互效应。温度升高、CO2浓度增加和氮沉降均能促进N2O排放,但不同变化因子交互作用对N2O排放的影响存在差异。未来应加强对多个变化因子交互作用的研究,不仅有助于进一步了解N2O产生的影响因素,而且能为将来土壤生态系统对全球环境变化的响应研究和预测模型的建立提供理论基础。 相似文献
9.
干湿交替灌溉具有节水稳产等优势,但也存在促进NH3挥发和增加N2O排放的风险。而生物炭具有改善土壤、蓄水保肥、降低温室气体排放等诸多正效应。为探究干湿交替灌溉条件下稻田活性氮气体排放(主要为NH3和N2O)对添加生物炭的响应机制,设置不同灌溉模式(淹灌和干湿交替灌溉)和生物炭用量(0和20 t/hm2)2个因素4个处理,通过2020和2021年大田原位试验,对稻田土壤环境、NH3挥发、N2O排放、植物氮素吸收和产量等进行了研究。结果表明,2 a间,干湿交替灌溉对水稻产量均未产生显著影响(P>0.05),但却显著增加了NH3挥发(仅2020年)和N2O排放(P<0.05),增幅分别达到8.9%和105.0%~115.0%;而添加生物炭显著降低了NH3挥发(8.7%~20.5%)和N2O排放(21.6%~24.2%)(P<0.05),减少9.0%~20.6... 相似文献
10.
11.
为促进氮肥高效利用,实现氮素污染减排,选用膨润土和生物炭作为包膜材料,结合硝化抑制剂制备包膜尿素。设置包膜尿素淋溶模拟试验收集淋溶液,结合静态箱法收集N2O,通过分析NH4+-N,NO3--N淋失量和N2O排放通量对包膜尿素氮素污染减排潜力进行了评估。结果表明:(1)膨润混合土生物炭包膜尿素(F4)NH4+-N淋溶损失率最低,较纯化肥尿素(F1)NH4+-N淋溶损失率降低19.76%。(2)硝化抑制剂型膨润土生物炭包膜尿素(F5)NO3--N淋失率最低,较F1降低16.74%。(3)F5同时具有最优的N2O减排效果,N2O排放量较F1降低77.8%。F5氮素减排效果最优,其减排机制在于一方面硝化抑制剂可以从化学过程控制硝化和反硝化进程,延缓尿素酰胺态氮的水解和铵态氮的硝化,在降低NO3--N淋失的同时可以实现N2O减排。另一方面F5的包膜材料膨润土和生物炭可以通过吸附作用将更多的NH4+-N富集在土壤表层,从而显著降低NH4+-N淋失。综上所述,硝化抑制剂型膨润土生物炭包膜尿素氮素污染减排潜力最优,可使NH4+-N,NO3--N和N2O分别减排15.24%,16.74%和77.8%。 相似文献
12.
Janaina Braga do Carmo Marisa de Cssia Piccolo Cristiano Alberto de Andrade Carlos Eduardo Pellegrino Cerri Brigitte Josefine Feigl Erclito Sousa Neto Carlos Clemente Cerri 《Soil & Tillage Research》2007,96(1-2):250-259
Anthropogenic conversion of primary forest to pasture for cattle production is still frequent in the Amazon Basin. Practices adopted by ranchers to restore productivity to degraded pasture have the potential to alter soil N availability and N gas losses from soils. We examined short-term (35 days) effects of tillage prior to pasture re-establishment on soil N availability, CO2, NO and N2O fluxes and microbial biomass C and N under degraded pasture at Nova Vida ranch, Rondônia, Brazilian Amazon. We collected soil samples and measured gas fluxes in tilled and control (non tilled pasture) 12 times at equally spaced intervals during October 2001 to quantify the effect of tillage. Maximum soil NH4+ and NO3− pools were 13.2 and 6.3 kg N ha−1 respectively after tillage compared to 0.24 and 6.3 kg N ha−1 in the control. Carbon dioxide flux ranged from 118 to 181 mg C–CO2 m2 h−1 in the control (non-tilled) and from 110 to 235 mg C–CO2 m2 h−1 when tilled. Microbial biomass C varied from 365 to 461 μg g−1 in the control and from 248 to 535 μg g−1 when tilled. The values for N2O fluxes ranged from 1.22 to 96.9 μg N m−2 h−1 in the tilled plots with a maximum 3 days after the second tilling. Variability in NO flux in the control and when tilled was consistent with previous measures of NO emissions from pasture at Nova Vida. When tilled, the NO/N2O ratio remained <1 after the first tilling suggesting that denitrification dominated N cycling. The effects of tilling on microbial parameters were less clear, except for a decrease in qCO2 and an increase in microbial biomass C/N immediately after tilling. Our results suggest that restoration of degraded pastures with tillage will lead to less C matter, at least initially. Further long-term research is needed. 相似文献
13.
Effects of disturbance and glucose addition on nitrous oxide and carbon dioxide emissions from a paddy soil 总被引:1,自引:0,他引:1
The effects of disturbance and glucose addition on N2O and CO2 emissions from a paddy soil at 45% WFPS (water-filled pore space) and at 25 °C were determined. During a 45-day incubation, disturbances with and without glucose addition were imposed 0, 1, 3, and 5 times. The total amount of glucose added to soil with 1, 3, and 5 disturbances was equal (0.6% of oven-dry soil basis). Strong nitrification occurred in the paddy soil during the incubation. Disturbance alone did not influence N2O and CO2 emissions significantly, but disturbance with glucose addition did (P < 0.01). A flush of N2O as well as CO2 was always observed following disturbance with glucose addition. The discrepancy in N2O emission between disturbance alone and disturbance with glucose addition was ascribed to the different magnitude of denitrification and/or heterotrophic nitrification. Greater cumulative emission of N2O was observed in the treatment of three disturbance times with glucose addition (4.3 mg N kg−1 soil), compared with five disturbances with glucose addition (2.5 mg N kg−1 soil) and one disturbance with glucose addition (2.5 mg N kg−1 soil). Cumulative CO2 emission was significant larger in one and three disturbances with glucose addition than that five disturbance with glucose addition. Supplies of available organic C appear to be a critical factor controlling denitrification and/or heterotrophic nitrification processes and N2O emission under relatively low moisture conditions, i.e. 45% WFPS. 相似文献
14.
Anaerobic flasks with two different soils contained microorganisms which effectively reduced NO3− to N2 in the absence of C2H2 and in the presence or absence of CO2. In the presence of C2H2, the microorganisms reduced NO3− to N2O and the further reduction of N2O to N2 was temporarily inhibited. This was shown for two partial pressures of C2H2 (0.1 kPa and 1.0 kPa). However. after a maximum of 168 h, microorganisms were able to reduce N2O to N2 in the presence of C2H2. This was shown in the presence of CO2 for both partial pressures of C2H2 and in the absence of CO2 for 1.0 kPa C2H2. The absence of CO2 delayed the complete reduction of N2O. Microorganisms which had reduced N2O in the presence of C2H2 retained this ability for at least 3 days after the original atmosphere containing C2H2 had been removed. 相似文献
15.
土壤反硝化作用是土壤N2O产生的重要过程,亚硝酸盐还原酶(NIR)催化的亚硝态氮(NO-2)还原为一氧化氮(NO)是反硝化作用的关键环节,研究长期施肥对反硝化微生物的影响及其与N2O排放的关系对于全面理解土壤反硝化过程具有重要意义。基于28年的旱作雨养长期施肥试验,通过常规监测、定量PCR和高通量测序等探讨了长期不同施肥(不施肥CK、偏施肥的单施氮肥N和氮钾配施NK、以及氮磷钾平衡施肥NPK)下土N2O排放和nirS反硝化细菌群落特征及两者之间的关系。结果表明:长期化肥施用(N,NK和NPK)均显著提高了N2O累积排放量,其中平衡施肥(NPK)最高。长期化肥施用对nirS基因丰度和nirS型反硝化细菌的α-多样性无显著影响,但长期平衡施用化肥提高了uncultured_bacterium_2303和Rhodanobacter_sp._D206a的相对丰度,降低了unclassified_k_norank_d_Bacteria和unclassified_p_Proteobacteria的相对丰度,从而改变了nirS型反硝化细菌的群落结构组成。雨养旱作条件下,土壤有机碳(SOC)、全氮(TN)、有效磷(AP)和pH等土壤性质是土nirS型反硝化细菌群落结构组成变化的主要影响因素。土nirS型反硝化细菌群落结构组成对土壤N2O排放具有显著影响,而nirS基因丰度和nirS型反硝化细菌多样性并没有显著影响。 相似文献
16.
17.
有机肥和秸秆炭分别替代部分尿素和秸秆降低黑土温室效应的效果 总被引:1,自引:1,他引:0