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1.
Yanghui He Xuhui Zhou Liling Jiang Ming Li Zhenggang Du Guiyao Zhou Junjiong Shao Xihua Wang Zhihong Xu Shahla Hosseini Bai Helen Wallace Chengyuan Xu 《Global Change Biology Bioenergy》2017,9(4):743-755
Biochar application to soils may increase carbon (C) sequestration due to the inputs of recalcitrant organic C. However, the effects of biochar application on the soil greenhouse gas (GHG) fluxes appear variable among many case studies; therefore, the efficacy of biochar as a carbon sequestration agent for climate change mitigation remains uncertain. We performed a meta‐analysis of 91 published papers with 552 paired comparisons to obtain a central tendency of three main GHG fluxes (i.e., CO2, CH4, and N2O) in response to biochar application. Our results showed that biochar application significantly increased soil CO2 fluxes by 22.14%, but decreased N2O fluxes by 30.92% and did not affect CH4 fluxes. As a consequence, biochar application may significantly contribute to an increased global warming potential (GWP) of total soil GHG fluxes due to the large stimulation of CO2 fluxes. However, soil CO2 fluxes were suppressed when biochar was added to fertilized soils, indicating that biochar application is unlikely to stimulate CO2 fluxes in the agriculture sector, in which N fertilizer inputs are common. Responses of soil GHG fluxes mainly varied with biochar feedstock source and soil texture and the pyrolysis temperature of biochar. Soil and biochar pH, biochar applied rate, and latitude also influence soil GHG fluxes, but to a more limited extent. Our findings provide a scientific basis for developing more rational strategies toward widespread adoption of biochar as a soil amendment for climate change mitigation. 相似文献
2.
生物质炭化还田对稻田温室气体排放及土壤理化性质的影响 总被引:16,自引:0,他引:16
通过水稻种植田间试验,研究了水稻秸秆直接还田、水稻秸秆与生活垃圾炭化后还田对稻田温室气体CH4、CO2和N2O排放及土壤理化性质和水稻产量的影响.结果表明:与直接还田相比,秸秆炭化后还田可显著降低稻田CH4和N2O的累积排放量,降幅分别为64.2%~78.5%和16.3%~18.4%.与不添加生物炭相比,无论种植水稻与否,添加秸秆炭和垃圾炭均显著降低了稻田N2O的累积排放量;不种植水稻情况下,添加垃圾炭显著降低了稻田CO2的累积排放量,降幅为25.3%.秸秆炭对提高稻田土壤pH和速效钾含量的作用优于垃圾炭.两种生物炭均能显著提高稻田土壤有机碳含量,但对土壤容重、全氮、有效磷、阳离子交换量及水稻籽粒产量均未产生显著影响.与秸秆直接还田相比,秸秆炭化后还田对水稻增产的效果更佳. 相似文献
3.
有机、无机氮肥施用对苜蓿产量、土壤硝态氮和温室气体排放的影响 总被引:1,自引:0,他引:1
2012年5月—2014年6月,采用田间小区试验方法,研究了不同氮肥管理对N2O与CH4的排放、土壤硝态氮含量以及苜蓿干草产量的影响.试验共设5个处理:对照(CK)、单施尿素处理(100 kg N·hm-2, CF)、尿素(100 kg N·hm-2)与腐熟牛粪(60 kg N·hm-2)混施处理(DM1)、尿素(100 kg N·hm-2)与沼液(60 kg N·hm-2)混施处理(DT)及减量尿素(40 kg N·hm-2)与牛粪(60 kg N·hm-2)混施处理(DM2).结果表明: 与CK相比,CF、DM1、DT和DM2处理苜蓿干草产量分别增加44.2%、38.9%、56.3%和30.6%,N2O排放分别比对照增加52.2%、89.1%、133.7%和59.4%,但各施肥处理对甲烷吸收表现出不同程度的抑制作用.苜蓿生产中,尿素和牛粪处理N2O-N排放与肥料氮素投入量比值(排放系数)为0.25%~0.28%,而沼液处理N2O-N排放系数为0.64%,显著高于前者.苜蓿生产中,施用化肥或有机无机混施均能显著增加苜蓿干物质产量,土壤硝态氮深层淋洗风险较小,但增加了CO2-equivalent净排放量. 相似文献
4.
生物黑炭对旱地土壤CO2、CH4、N2O排放及其环境效益的影响 总被引:9,自引:0,他引:9
采用土柱室内模拟的方法,通过添加0%、0.5%、2%、4%、6%、8%生物黑炭于土壤中,测定土壤CO2、CH4、N2O排放通量,探讨生物黑炭对旱地土壤CO2、CH4、N2O排放及其环境效益的影响。结果表明:室内模拟土柱培养期内,施用生物黑炭能显著增加CO2排放,且生物黑炭添加百分数(x)与CO2累积排放量(y)之间满足线性方程:y=12.591x+235.02(R2=0.834,n=24);当生物黑炭添加量达到2%及以上时,基本抑制了CH4的排放和显著减少土壤N2O排放,并显著减少CH4和N2O的综合温室效应,当其达到4%以上时,CH4和N2O的综合温室效应降幅更大并趋于稳定,但施用少量生物黑炭(0.5%)可显著促进N2O排放,对减少CH4和N2O综合温室效应并无明显效果。生物黑炭表观分解率随其添加量的增加逐渐减少,生物黑炭添加比例越高,积累于土壤中的碳越多,从投入生物黑炭量与固碳量和减排比角度综合考虑,农业生产中推荐生物黑炭施用量为20 t/hm2,其固碳减排效果俱佳。 相似文献
5.
PINGPING WU JINJIAN LIU YANGCHUN XU QIRONG SHEN JIANWEN ZOU SHIWEI GUO 《Global Change Biology》2011,17(6):2196-2210
The impact of agricultural management on global warming potential (GWP) and greenhouse gas intensity (GHGI) is not well documented. A long‐term fertilizer experiment in Chinese double rice‐cropping systems initiated in 1990 was used in this study to gain an insight into a complete greenhouse gas accounting of GWP and GHGI. The six fertilizer treatments included inorganic fertilizer [nitrogen and phosphorus fertilizer (NP), nitrogen and potassium fertilizer (NK), and balanced inorganic fertilizer (NPK)], combined inorganic/organic fertilizers at full and reduced rate (FOM and ROM), and no fertilizer application as a control. Methane (CH4) and nitrous oxide (N2O) fluxes were measured using static chamber method from November 2006 through October 2009, and the net ecosystem carbon balance was estimated by the changes in topsoil (0–20 cm) organic carbon (SOC) density over the 10‐year period 1999–2009. Long‐term fertilizer application significantly increased grain yields, except for no difference between the NK and control plots. Annual topsoil SOC sequestration rate was estimated to be 0.96 t C ha?1 yr?1 for the control and 1.01–1.43 t C ha?1 yr?1 for the fertilizer plots. Long‐term inorganic fertilizer application tended to increase CH4 emissions during the flooded rice season and significantly increased N2O emissions from drained soils during the nonrice season. Annual mean CH4 emissions ranged from 621 kg CH4 ha?1 for the control to 1175 kg CH4 ha?1 for the FOM plots, 63–83% of which derived from the late‐rice season. Annual N2O emission averaged 1.15–4.11 kg N2O–N ha?1 in the double rice‐cropping systems. Compared with the control, inorganic fertilizer application slightly increased the net annual GWPs, while they were remarkably increased by combined inorganic/organic fertilizer application. The GHGI was lowest for the NP and NPK plots and highest for the FOM and ROM plots. The results of this study suggest that agricultural economic viability and GHGs mitigation can be simultaneously achieved by balanced fertilizer application. 相似文献
6.
Maria Chiara Rosace Fabio Veronesi Stephen Briggs Laura M. Cardenas Simon Jeffery 《Global Change Biology Bioenergy》2020,12(6):445-457
The application of organic materials to soil can recycle nutrients and increase organic matter in agricultural lands. Digestate can be used as a nutrient source for crop production but it has also been shown to stimulate greenhouse gas (GHG) emissions from amended soils. While edaphic factors, such as soil texture and pH, have been shown to be strong determinants of soil GHG fluxes, the impact of the legacy of previous management practices is less well understood. Here we aim to investigate the impact of such legacy effects and to contrast them against soil properties to identify the key determinants of soil GHG fluxes following digestate application. Soil from an already established field experiment was used to set up a pot experiment, to evaluate N2O, CH4 and CO2 fluxes from cattle‐slurry‐digestate amended soils. The soil had been treated with farmyard manure, green manure or synthetic N‐fertilizer, 18 months before the pot experiment was set up. Following homogenization and a preincubation stage, digestate was added at a concentration of 250 kg total N/ha eq. Soil GHG fluxes were then sampled over a 64 day period. The digestate stimulated emissions of the three GHGs compared to controls. The legacy of previous soil management was found to be a key determinant of CO2 and N2O flux while edaphic variables did not have a significant effect across the range of variables included in this experiment. Conversely, edaphic variables, in particular texture, were the main determinant of CH4 flux from soil following digestate application. Results demonstrate that edaphic factors and current soil management regime alone are not effective predictors of soil GHG flux response following digestate application. Knowledge of the site management in terms of organic amendments is required to make robust predictions of the likely soil GHG flux response following digestate application to soil. 相似文献
7.
Molecular mechanisms of water table lowering and nitrogen deposition in affecting greenhouse gas emissions from a Tibetan alpine wetland 总被引:1,自引:0,他引:1
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Hao Wang Lingfei Yu Zhenhua Zhang Wei Liu Litong Chen Guangmin Cao Haowei Yue Jizhong Zhou Yunfeng Yang Yanhong Tang Jin‐Sheng He 《Global Change Biology》2017,23(2):815-829
Rapid climate change and intensified human activities have resulted in water table lowering (WTL) and enhanced nitrogen (N) deposition in Tibetan alpine wetlands. These changes may alter the magnitude and direction of greenhouse gas (GHG) emissions, affecting the climate impact of these fragile ecosystems. We conducted a mesocosm experiment combined with a metagenomics approach (GeoChip 5.0) to elucidate the effects of WTL (?20 cm relative to control) and N deposition (30 kg N ha?1 yr?1) on carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes as well as the underlying mechanisms. Our results showed that WTL reduced CH4 emissions by 57.4% averaged over three growing seasons compared with no‐WTL plots, but had no significant effect on net CO2 uptake or N2O flux. N deposition increased net CO2 uptake by 25.2% in comparison with no‐N deposition plots and turned the mesocosms from N2O sinks to N2O sources, but had little influence on CH4 emissions. The interactions between WTL and N deposition were not detected in all GHG emissions. As a result, WTL and N deposition both reduced the global warming potential (GWP) of growing season GHG budgets on a 100‐year time horizon, but via different mechanisms. WTL reduced GWP from 337.3 to ?480.1 g CO2‐eq m?2 mostly because of decreased CH4 emissions, while N deposition reduced GWP from 21.0 to ?163.8 g CO2‐eq m?2, mainly owing to increased net CO2 uptake. GeoChip analysis revealed that decreased CH4 production potential, rather than increased CH4 oxidation potential, may lead to the reduction in net CH4 emissions, and decreased nitrification potential and increased denitrification potential affected N2O fluxes under WTL conditions. Our study highlights the importance of microbial mechanisms in regulating ecosystem‐scale GHG responses to environmental changes. 相似文献
8.
Janaina Braga do Carmo Solange Filoso Luciana C. Zotelli Eraclito R. de Sousa Neto Leonardo M. Pitombo Paulo J. Duarte‐Neto Vitor P. Vargas Cristiano A. Andrade Glauber J. C. Gava Raffaella Rossetto Heitor Cantarella André E. Neto Luiz A. Martinelli 《Global Change Biology Bioenergy》2013,5(3):267-280
Bioethanol from sugarcane is becoming an increasingly important alternative energy source worldwide as it is considered to be both economically and environmentally sustainable. Besides being produced from a tropical perennial grass with high photosynthetic efficiency, sugarcane ethanol is commonly associated with low N fertilizer use because sugarcane from Brazil, the world's largest sugarcane producer, has a low N demand. In recent years, several models have predicted that the use of sugarcane ethanol in replacement to fossil fuel could lead to high greenhouse gas (GHG) emission savings. However, empirical data that can be used to validate model predictions and estimates from indirect methodologies are scarce, especially with regard to emissions associated with different fertilization methods and agricultural management practices commonly used in sugarcane agriculture in Brazil. In this study, we provide in situ data on emissions of three GHG (CO2, N2O, and CH4) from sugarcane soils in Brazil and assess how they vary with fertilization methods and management practices. We measured emissions during the two main phases of the sugarcane crop cycle (plant and ratoon cane), which include different fertilization methods and field conditions. Our results show that N2O and CO2 emissions in plant cane varied significantly depending on the fertilization method and that waste products from ethanol production used as organic fertilizers with mineral fertilizer, as it is the common practice in Brazil, increase emission rates significantly. Cumulatively, the highest emissions were observed for ratoon cane treated with vinasse (liquid waste from ethanol production) especially as the amount of crop trash on the soil surface increased. Emissions of CO2 and N2O were 6.9 kg ha?1 yr?1 and 7.5 kg ha?1 yr?1, respectively, totaling about 3000 kg in CO2 equivalent ha?1 yr?1. 相似文献
9.
Soil and greenhouse gas responses to biochar additions in a temperate hardwood forest 总被引:2,自引:0,他引:2
Tara E. Sackett Nathan Basiliko Genevieve L. Noyce Carolyn Winsborough Jonathan Schurman Chihiro Ikeda Sean C. Thomas 《Global Change Biology Bioenergy》2015,7(5):1062-1074
Biochar additions can improve soil fertility and sequester carbon, but biochar effects have been investigated primarily in agricultural systems. Biochar from spruce and maple sawdust feedstocks (with and without inorganic phosphorus in a factorial design) were added to plots in a commercially managed temperate hardwood forest stand in central Ontario, Canada; treatments were applied as a top‐dressing immediately prior to fall leaf abscission in September 2011. Forests in this region have acidic, sandy soils, and due to nitrogen deposition may exhibit phosphorus, calcium, and magnesium limitation. To investigate short‐term impacts of biochar application on soil nutrient supply and greenhouse gas fluxes as compared to phosphorus fertilization, data were collected over the first year after treatment application; linear mixed models were used to analyze data. Two to six weeks after treatment application, there were higher concentrations of potassium in spruce and maple biochar plots, and phosphorus in spruce biochar plots, as compared to the control treatment. There were higher concentrations of calcium, magnesium, and phosphorus in the phosphorus plots. In the following spring and summer (9–12 months after treatment application), there were higher soil calcium concentrations in maple biochar plots, and phosphorus plots still had higher soil phosphorus concentrations than control plots. No treatment effects on fluxes of carbon dioxide, methane, or nitrous oxide were detected in the field; however, laboratory incubations after 12 months showed higher microbial respiration in soils from maple biochar plots as compared to spruce biochar, despite no effect on microbial biomass. The results suggest that the most important short‐term impact of biochar additions in this system is the increased supply of the limiting plant nutrients phosphorus and calcium. We expect that larger changes in mineral soil physical and chemical properties will occur when the surface‐applied biochar becomes incorporated into the soil after a few years. 相似文献
10.
Woody biochar's greenhouse gas mitigation potential across fertilized and unfertilized agricultural soils and soil moisture regimes
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Biochar has been widely researched as an important technology for climate smart agriculture, yet work is still necessary to identify the magnitude of potential greenhouse gas (GHG) mitigation and mechanisms involved. This study measured slow‐pyrolysis wood‐derived biochar's impact on GHG efflux, mineral N dynamics, and soil organic C in a series of two incubations across fertilized and unfertilized agricultural soils and soil moisture regimes. This research explored the magnitude of biochar's full GHG mitigation potential and drivers of such impacts. Results of this incubation indicate slow‐pyrolysis wood‐derived biochar has potential to provide annual emission reductions of 0.58–1.72 Mg CO2‐eq ha?1 at a 25 Mg ha?1 biochar application rate. The greatest GHG mitigation potential was from C sequestration and nitrous oxide (N2O) reduction in mineral N fertilized soils, with minimal impacts on N2O emissions in unfertilized soils, carbon dioxide (CO2) emissions, and methane (CH4) uptake. Analysis of mineral N dynamics in the bulk soil and on biochar isolates indicated that neither biochar impacts on net mineralization and nitrification nor retention of ammonium () on biochar isolates could explain biochar's N2O reduction. Instead, biochar amendments exhibited consistent N2O emission reductions relative to the N2O emission in the control soil regardless of soil type and fertilization. Results across a soil moisture gradient suggest that woody biochar may aerate soils shifting redox conditions and subsequent N2O production. Understanding the magnitude of biochar's GHG reduction potential and the mechanisms driving these effects can help inform biochar modeling efforts, explain field results and identify agricultural applications that maximize biochar's full GHG mitigation potential. 相似文献
11.
Junyi Liang Jiangyang Xia Zheng Shi Lifen Jiang Shuang Ma Xingjie Lu Marguerite Mauritz Susan M. Natali Elaine Pegoraro Christopher Ryan Penton César Plaza Verity G. Salmon Gerardo Celis James R. Cole Konstantinos T. Konstantinidis James M. Tiedje Jizhong Zhou Edward A. G. Schuur Yiqi Luo 《Global Change Biology》2018,24(10):4946-4959
Climate warming can result in both abiotic (e.g., permafrost thaw) and biotic (e.g., microbial functional genes) changes in Arctic tundra. Recent research has incorporated dynamic permafrost thaw in Earth system models (ESMs) and indicates that Arctic tundra could be a significant future carbon (C) source due to the enhanced decomposition of thawed deep soil C. However, warming‐induced biotic changes may influence biologically related parameters and the consequent projections in ESMs. How model parameters associated with biotic responses will change under warming and to what extent these changes affect projected C budgets have not been carefully examined. In this study, we synthesized six data sets over 5 years from a soil warming experiment at the Eight Mile Lake, Alaska, into the Terrestrial ECOsystem (TECO) model with a probabilistic inversion approach. The TECO model used multiple soil layers to track dynamics of thawed soil under different treatments. Our results show that warming increased light use efficiency of vegetation photosynthesis but decreased baseline (i.e., environment‐corrected) turnover rates of SOC in both the fast and slow pools in comparison with those under control. Moreover, the parameter changes generally amplified over time, suggesting processes of gradual physiological acclimation and functional gene shifts of both plants and microbes. The TECO model predicted that field warming from 2009 to 2013 resulted in cumulative C losses of 224 or 87 g/m2, respectively, without or with changes in those parameters. Thus, warming‐induced parameter changes reduced predicted soil C loss by 61%. Our study suggests that it is critical to incorporate biotic changes in ESMs to improve the model performance in predicting C dynamics in permafrost regions. 相似文献
12.
Helen C. Flynn Llorenç Milà i. Canals Emma Keller Henry King Sarah Sim Astley Hastings Shifeng Wang Pete Smith 《Global Change Biology》2012,18(5):1622-1635
Many assessments of product carbon footprint (PCF) for agricultural products omit emissions arising from land‐use change (LUC). In this study, we developed a framework based on IPCC national greenhouse gas inventory methodologies to assess the impacts of LUC from crop production using oil palm, soybean and oilseed rape as examples. Using ecological zone, climate and soil types from the top 20 producing countries, calculated emissions for transitions from natural vegetation to cropland on mineral soils under typical management ranged from ?4.5 to 29.4 t CO2‐eq ha?1 yr?1 over 20 years for oil palm and 1.2–47.5 t CO2‐eq ha?1 yr?1 over 20 years for soybeans. Oilseed rape showed similar results to soybeans, but with lower maximum values because it is mainly grown in areas with lower C stocks. GHG emissions from other land‐use transitions were between 62% and 95% lower than those from natural vegetation for the arable crops, while conversions to oil palm were a sink for C. LUC emissions were considered on a national basis and also expressed per‐tonne‐of‐oil‐produced. Weighted global averages indicate that, depending on the land‐use transition, oil crop production on newly converted land contributes between ?3.1 and 7.0 t CO2‐eq t oil production?1 yr?1 for palm oil, 11.9–50.6 t CO2‐eq t oil production?1 yr?1 for soybean oil, and 7.7–31.4 t CO2‐eq t oil production?1 yr?1 for rapeseed oil. Assumptions made about crop and LUC distribution within countries contributed up to 66% error around the global averages for natural vegetation conversions. Uncertainty around biomass and soil C stocks were also examined. Finer resolution data and information (particularly on land management and yield) could improve reliability of the estimates but the framework can be used in all global regions and represents an important step forward for including LUC emissions in PCFs. 相似文献
13.
Bärbel Tiemeyer Elisa Albiac Borraz Jürgen Augustin Michel Bechtold Sascha Beetz Colja Beyer Matthias Drösler Martin Ebli Tim Eickenscheidt Sabine Fiedler Christoph Förster Annette Freibauer Michael Giebels Stephan Glatzel Jan Heinichen Mathias Hoffmann Heinrich Höper Gerald Jurasinski Katharina Leiber‐Sauheitl Mandy Peichl‐Brak Niko Roßkopf Michael Sommer Jutta Zeitz 《Global Change Biology》2016,22(12):4134-4149
Drainage has turned peatlands from a carbon sink into one of the world's largest greenhouse gas (GHG) sources from cultivated soils. We analyzed a unique data set (12 peatlands, 48 sites and 122 annual budgets) of mainly unpublished GHG emissions from grasslands on bog and fen peat as well as other soils rich in soil organic carbon (SOC) in Germany. Emissions and environmental variables were measured with identical methods. Site‐averaged GHG budgets were surprisingly variable (29.2 ± 17.4 t CO2‐eq. ha?1 yr?1) and partially higher than all published data and the IPCC default emission factors for GHG inventories. Generally, CO2 (27.7 ± 17.3 t CO2 ha?1 yr?1) dominated the GHG budget. Nitrous oxide (2.3 ± 2.4 kg N2O‐N ha?1 yr?1) and methane emissions (30.8 ± 69.8 kg CH4‐C ha?1 yr?1) were lower than expected except for CH4 emissions from nutrient‐poor acidic sites. At single peatlands, CO2 emissions clearly increased with deeper mean water table depth (WTD), but there was no general dependency of CO2 on WTD for the complete data set. Thus, regionalization of CO2 emissions by WTD only will remain uncertain. WTD dynamics explained some of the differences between peatlands as sites which became very dry during summer showed lower emissions. We introduced the aerated nitrogen stock (Nair) as a variable combining soil nitrogen stocks with WTD. CO2 increased with Nair across peatlands. Soils with comparatively low SOC concentrations showed as high CO2 emissions as true peat soils because Nair was similar. N2O emissions were controlled by the WTD dynamics and the nitrogen content of the topsoil. CH4 emissions can be well described by WTD and ponding duration during summer. Our results can help both to improve GHG emission reporting and to prioritize and plan emission reduction measures for peat and similar soils at different scales. 相似文献
14.
Effect of improved nitrogen management on greenhouse gas emissions from intensive dairy systems in the Netherlands 总被引:1,自引:0,他引:1
R. L. M. SCHILS A. VERHAGEN H. F. M. AARTS P. J. KUIKMAN† L. B. J. EBEK‡ 《Global Change Biology》2006,12(2):382-391
Dairy systems in Europe contribute to the emissions of the greenhouse gases (GHGs) nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2). In this paper, the effects of improved nitrogen (N) management on GHG emissions from Dutch dairy farms are determined. The GHG emissions are calculated using the panel on climate change (IPCC) methodology for the Netherlands, an updated and refined IPCC methodology, and a full accounting approach. The changes in dairy farming over the last 20 years, and the consequences for N management are described using detailed farm‐level data, collected in 1985, 1997 and 2002. The selected years represent distinct stages in the implementation of N policies. The changes in N management have reduced the GHG emissions. A reduction of the N surplus per kilogram milk with 1 g N reduced the GHG emissions per kilogram milk with approximately 29 g CO2‐equivalents. The reduction of the N surpluses was mainly brought about by reduced fertilizer use and reduced grazing time. The use of updated and refined emission factors resulted in higher CH4 emissions and lower N2O emissions. On average, the overall emission was 36% higher with the refined method. Full accounting, including all direct and indirect emissions of CH4, N2O and CO2, increased the emission with 36% compared with the refined IPCC methodology. We conclude that the N surplus at farm level is a useful indicator of GHG emissions. A full accounting system as presented in this study may effectively enable farmers to address the issue of emissions of GHGs in their operational management decisions. Both approaches serve their own specific objectives: full accounting at the farm level to explore mitigation options, and the IPCC methods to report changes in GHG emissions at the national level. 相似文献
15.
Shuwei Liu Chun Zhao Yaojun Zhang Zhiqiang Hu Cong Wang Yajie Zong Ling Zhang Jianwen Zou 《Global Change Biology Bioenergy》2015,7(4):690-703
A full accounting of net greenhouse gas balance (NGHGB) and greenhouse gas intensity (GHGI) was examined in an annual coastal reclaimed saline Jerusalem artichoke-fallow cropping system under various soil practices including soil tillage, soil ameliorant, and crop residue amendments. Seasonal fluxes of soil carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) were measured using static chamber method, and the net ecosystem exchange of CO2 (NEE) was determined by the difference between soil heterotrophic respiration (RH) and net primary production (NPP). Relative to no-tillage, rotary tillage significantly decreased the NPP of Jerusalem artichoke while it had no significant effects on the annual RH. Rotary tillage increased CH4 emissions, while seasonal or annual soil N2O emissions did not statistically differ between the two tillage treatments. Compared with the control plots, soil ameliorant or straw amendment enhanced RH, soil CH4, and N2O emissions under the both tillage regimes. Annual NGHGB was negative for all the field treatments, as a consequence of net ecosystem CO2 sequestration exceeding the CO2-equivalents released as CH4 and N2O emissions, which indicates that Jerusalem artichoke-fallow cropping system served as a net sink of GHGs. The annual net NGHGB and GHGI were estimated to be 11–21% and 4–8% lower in the NT than in RT cropping systems, respectively. Soil ameliorant and straw amendments greatly increased NPP and thus significantly decreased the negative annual net NGHGB. Overall, higher NPP but lower climatic impacts of coastal saline bioenergy production would be simultaneously achieved by Jerusalem artichoke cultivation under no-tillage with improved saline soil conditions in southeast China. 相似文献
16.
The influence of forest stand age in a Picea sitchensis plantation on (1) soil fluxes of three greenhouse gases (GHGs – CO2, CH4 and N2O) and (2) overall net ecosystem global warming potential (GWP), was investigated in a 2‐year study. The objective was to isolate the effect of forest stand age on soil edaphic characteristics (temperature, water table and volumetric moisture) and the consequent influence of these characteristics on the GHG fluxes. Fluxes were measured in a chronosequence in Harwood, England, with sites comprising 30‐ and 20‐year‐old second rotation forest and a site clearfelled (CF) some 18 months before measurement. Adjoining unforested grassland (UN) acted as a control. Comparisons were made between flux data, soil temperature and moisture data and, at the 30‐year‐old and CF sites, eddy covariance data for net ecosystem carbon (C) exchange (NEE). The main findings were: firstly, integrated CO2 efflux was the dominant influence on the GHG budget, contributing 93–94% of the total GHG flux across the chronosequence compared with 6–7% from CH4 and N2O combined. Secondly, there were clear links between the trends in edaphic factors as the forest matured, or after clearfelling, and the emission of GHGs. In the chronosequence sites, annual fluxes of CO2 were lower at the 20‐year‐old (20y) site than at the 30‐year‐old (30y) and CF sites, with soil temperature the dominant control. CH4 efflux was highest at the CF site, with peak flux 491±54.5 μg m−2 h−1 and maximum annual flux 18.0±1.1 kg CH4 ha−1 yr−1. No consistent uptake of CH4 was noted at any site. A linear relationship was found between log CH4 flux and the closeness of the water table to the soil surface across all sites. N2O efflux was highest in the 30y site, reaching 108±38.3 μg N2O‐N m−2 h−1 (171 μg N2O m−2 h−1) in midsummer and a maximum annual flux of 4.7±1.2 kg N2O ha−1 yr−1 in 2001. Automatic chamber data showed a positive exponential relationship between N2O flux and soil temperature at this site. The relationship between N2O emission and soil volumetric moisture indicated an optimum moisture content for N2O flux of 40–50% by volume. The relationship between C : N ratio data and integrated N2O flux was consistent with a pattern previously noted across temperate and boreal forest soils. 相似文献
17.
M. L. Cabrera S. C. Chiang W. C. Merka O. C. Pancorbo S. A. Thompson 《Plant and Soil》1994,163(2):189-195
While several studies have shown that the addition of animal manures to soil can increase N2O and CO2 emissions, limited information is available on the effect that manure physical characteristics can have on these emissions. This study compared N2O and CO2 emissions from poultry litter incorporated as pellets (5.5 mm OD, 7 mm long) or fine particles (<0.83 mm) into Cecil soil samples. The soil-litter mixture was packed in acrylic plastic cylinders and adjusted to 55 or 90 % water-filled porosity (WFP). The cylinders were placed inside jars that were sealed and placed in an incubator at 25°C for 35 d, with periodic air samplings conducted for N2O and CO2 analyses. At 55% WFP, cumulative emission of CO2 was similar for both litter types, but cumulative emission of N2O was slightly higher for pelletized (6.8 % of applied N) than for fine-particle litter (5.5 %). In contrast, at 90 % WFP, cumulative emission of N2O was larger for fine-particle litter (3.4 % of applied N) than for pelletized litter (1.5 %). These results indicate that the effect of poultry litter physical characteristics on N2O emissions from incorporated applications can be expected to vary depending on the soil water regime. 相似文献
18.
Linfeng Li Zhenzhen Zheng Weijin Wang Joel A. Biederman Xingliang Xu Qinwei Ran Ruyan Qian Cong Xu Biao Zhang Fang Wang Shutong Zhou Lizhen Cui Rongxiao Che Yanbin Hao Xiaoyong Cui Zhihong Xu Yanfen Wang 《Global Change Biology》2020,26(2):931-943
Nitrous oxide (N2O) emissions from soil contribute to global warming and are in turn substantially affected by climate change. However, climate change impacts on N2O production across terrestrial ecosystems remain poorly understood. Here, we synthesized 46 published studies of N2O fluxes and relevant soil functional genes (SFGs, that is, archaeal amoA, bacterial amoA, nosZ, narG, nirK and nirS) to assess their responses to increased temperature, increased or decreased precipitation amounts, and prolonged drought (no change in total precipitation but increase in precipitation intervals) in terrestrial ecosystem (i.e. grasslands, forests, shrublands, tundra and croplands). Across the data set, temperature increased N2O emissions by 33%. However, the effects were highly variable across biomes, with strongest temperature responses in shrublands, variable responses in forests and negative responses in tundra. The warming methods employed also influenced the effects of temperature on N2O emissions (most effectively induced by open‐top chambers). Whole‐day or whole‐year warming treatment significantly enhanced N2O emissions, but daytime, nighttime or short‐season warming did not have significant effects. Regardless of biome, treatment method and season, increased precipitation promoted N2O emission by an average of 55%, while decreased precipitation suppressed N2O emission by 31%, predominantly driven by changes in soil moisture. The effect size of precipitation changes on nirS and nosZ showed a U‐shape relationship with soil moisture; further insight into biotic mechanisms underlying N2O emission response to climate change remain limited by data availability, underlying a need for studies that report SFG. Our findings indicate that climate change substantially affects N2O emission and highlights the urgent need to incorporate this strong feedback into most climate models for convincing projection of future climate change. 相似文献
19.
Response of soil carbon dioxide fluxes,soil organic carbon and microbial biomass carbon to biochar amendment: a meta‐analysis
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Shuwei Liu Yaojun Zhang Yajie Zong Zhiqiang Hu Shuang Wu Jie Zhou Yaguo Jin Jianwen Zou 《Global Change Biology Bioenergy》2016,8(2):392-406
Biochar as a carbon‐rich coproduct of pyrolyzing biomass, its amendment has been advocated as a potential strategy to soil carbon (C) sequestration. Updated data derived from 50 papers with 395 paired observations were reviewed using meta‐analysis procedures to examine responses of soil carbon dioxide (CO2) fluxes, soil organic C (SOC), and soil microbial biomass C (MBC) contents to biochar amendment. When averaged across all studies, biochar amendment had no significant effect on soil CO2 fluxes, but it significantly enhanced SOC content by 40% and MBC content by 18%. A positive response of soil CO2 fluxes to biochar amendment was found in rice paddies, laboratory incubation studies, soils without vegetation, and unfertilized soils. Biochar amendment significantly increased soil MBC content in field studies, N‐fertilized soils, and soils with vegetation. Enhancement of SOC content following biochar amendment was the greatest in rice paddies among different land‐use types. Responses of soil CO2 fluxes and MBC to biochar amendment varied with soil texture and pH. The use of biochar in combination with synthetic N fertilizer and waste compost fertilizer led to the greatest increases in soil CO2 fluxes and MBC content, respectively. Both soil CO2 fluxes and MBC responses to biochar amendment decreased with biochar application rate, pyrolysis temperature, or C/N ratio of biochar, while each increased SOC content enhancement. Among different biochar feedstock sources, positive responses of soil CO2 fluxes and MBC were the highest for manure and crop residue feedstock sources, respectively. Soil CO2 flux responses to biochar amendment decreased with pH of biochar, while biochars with pH of 8.1–9.0 had the greatest enhancement of SOC and MBC contents. Therefore, soil properties, land‐use type, agricultural practice, and biochar characteristics should be taken into account to assess the practical potential of biochar for mitigating climate change. 相似文献
20.
Potential impacts of climate change on nitrogen transformations and greenhouse gas fluxes in forests: a soil transfer study 总被引:1,自引:0,他引:1
STEPHEN C. HART 《Global Change Biology》2006,12(6):1032-1046
Relatively little research has been conducted on how climate change may affect the structure and function of arid to semiarid ecosystems of the American Southwest. Along the slopes of the San Francisco Peaks of Arizona, USA, I transferred intact soil cores from a spruce‐fir to a ponderosa pine forest 730 m lower in elevation to assess the potential impacts of climate change on soil N cycling and trace gas fluxes. The low‐elevation site has a mean annual soil temperature about 2.5°C higher than the high‐elevation site. Net rates of N transformations and trace gas fluxes were measured in high‐elevation soil cores incubated in situ and soil cores transferred to the low‐elevation site. Over a 13‐month period, volumetric soil water content was similar in transferred soil cores relative to soil cores incubated in situ. Net N mineralization and nitrification increased over 80% in transferred soil cores compared with in situ soil cores. Soil transfer significantly increased net CO2 efflux (120%) and net CH4 consumption (90%) relative to fluxes of these gases from soil cores incubated in situ. Soil net N2O fluxes were relatively low and were not generally altered by soil transfer. Although the soil microbial biomass as a whole decreased in transferred soil cores compared with in situ soil cores after the incubation period, active bacterial biomass increased. Transferring soil cores from the low‐elevation to the high‐elevation site (i.e. simulated global cooling) commonly, but not consistently, resulted in the opposite effects on soil pools and processes. In general, soil containment (root trenching) did not significantly affect soil measurements. My results suggest that small increases in mean annual temperature can have large impacts on soil N cycling, soil–atmosphere trace gas exchanges, and soil microbial communities even in ecosystems where water availability is a major limiting resource. 相似文献