Inconsistent increasing of climate potential productivity resulting from global warming and land use transitions in the Dongting Lake Basin,from 2000 to 2020

In the face of global warming and increasing impervious surfaces,quantifying the change of climate potential productivity(CPP)is of great significance for the food production planning.Targeting the Dongting Lake Basin,which is a key area for food production in China,this paper uses meteorological data,as well as Climate Change Initiative Land Cover,and Shuttle Radar Topography Mission digital elevation model to investigate the CPP and its changes from 2000 to 2020.The suitability of land for cultivation(SLC),and the land use/land cover change(LUCC)are also considered.The results showed that the CPP varied from 9,825 to 20,895 kg ha^(-1).Even though the newly added impervious surfaces indirectly resulted in the decrease of CPP by of 9.81×10~8 kg,overall,the CPP increased at an average rate of 83.7 kg ha^(-1)a^(-1).Global warming is the strongest driver behind CPP increase,and CPP has played an important role in the conversions between cultivated land and other land types.The structure of land types tends to be optimized against this challenge.

Modelling analysis embodies drastic transition among global potential natural vegetations in face of changing climate

Potential natural vegetation(PNV)is a valuable reference for ecosystem renovation and has garnered increasing attention worldwide.However,there is limited knowledge on the spatio-temporal distributions,transitional processes,and underlying mechanisms of global natural vegetation,particularly in the case of ongoing climate warming.In this study,we visualize the spatio-temporal pattern and inter-transition procedure of global PNV,analyse the shifting distances and directions of global PNV under the influence of climatic disturbance,and explore the mechanisms of global PNV in response to temperature and precipitation fluctuations.To achieve this,we utilize meteorological data,mainly temperature and precipitation,from six phases:the Last Inter-Glacial(LIG),the Last Glacial Maximum(LGM),the Mid Holocene(MH),the Present Day(PD),2030(20212040)and 2090(2081–2100),and employ a widely-accepted comprehensive and sequential classification sy–stem(CSCS)for global PNV classification.We find that the spatial patterns of five PNV groups(forest,shrubland,savanna,grassland and tundra)generally align with their respective ecotopes,although their distributions have shifted due to fluctuating temperature and precipitation.Notably,we observe an unexpected transition between tundra and savanna despite their geographical distance.The shifts in distance and direction of five PNV groups are mainly driven by temperature and precipitation,although there is heterogeneity among these shifts for each group.Indeed,the heterogeneity observed among different global PNV groups suggests that they may possess varying capacities to adjust to and withstand the impacts of changing climate.The spatio-temporal distributions,mutual transitions and shift tendencies of global PNV and its underlying mechanism in face of changing climate,as revealed in this study,can significantly contribute to the development of strategies for mitigating warming and promoting re-vegetation in degraded regions worldwide.

Biochar amendments increase soil organic carbon storage and decrease global warming potentials of soil CH4 and N2O under N addition in a subtropical Moso bamboo plantation

Background: Nitrogen(N) deposition affects soil greenhouse gas(GHG) emissions, while biochar application reduces GHG emissions in agricultural soils. However, it remains unclear whether biochar amendment can alleviate the promoting effects of N input on GHG emissions in forest soils. Here, we quantify the separate and combined effects of biochar amendment(0, 20, and 40 t·ha) and N addition(0, 30, 60, and 90 kg N·ha·yr) on soil GHG fluxes in a long-term field experiment at a Moso bamboo(Phyllostachys edulis) plantation.Results: Low and moderate N inputs(≤60 kg N·ha·yr) significantly increase mean annual soil carbon dioxide(CO) and nitrous oxide(NO) emissions by 17.0%–25.4% and 29.8%–31.2%, respectively, while decreasing methane(CH) uptake by 12.4%–15.9%, leading to increases in the global warming potential(GWP) of soil CHand NO fluxes by 32.4%–44.0%. Moreover, N addition reduces soil organic carbon(C;SOC) storage by 0.2%–6.5%. Compared to the control treatment, biochar amendment increases mean annual soil CO2emissions, CHuptake, and SOC storage by 18.4%–25.4%, 7.6%–15.8%, and 7.1%–13.4%, respectively, while decreasing NO emissions by 17.6%–19.2%, leading to a GWP decrease of 18.4%–21.4%. Biochar amendments significantly enhance the promoting effects of N addition on soil COemissions, while substantially offsetting the promotion of N2O emissions, inhibition of CHuptake, and decreased SOC storage, resulting in a GWP decrease of 9.1%–30.3%.Additionally, soil COand CHfluxes are significantly and positively correlated with soil microbial biomass C(MBC) and pH. Meanwhile, NO emissions have a significant and positive correlation with soil MBC and a negative correlation with pH.Conclusions: Biochar amendment can increase SOC storage and offset the enhanced GWP mediated by elevated N deposition and is, thus, a potential strategy for increasing soil C sinks and decreasing GWPs of soil CHand NO under increasing atmospheric N deposition in Moso bamboo plantations.

Change of Tropical Cyclone Heat Potential in Response to Global Warming

Tropical cyclone heat potential （TCHP） in the ocean can affect tropical cyclone intensity and intensification. In this paper, TCHP change under global warming is presented based on 35 models from CMIP5 （Coupled Model Intercomparison Project, Phase 5）. As the upper ocean warms up, the TCHP of the global ocean is projected to increase by 140.6% in the 21st century under the RCP4.5 （＋4.5 W m 2 Representative Concentration Pathway） scenario, The increase is particularly significant in the western Pacific, northwestern Indian and western tropical Atlantic oceans. The increase of TCHP results from the ocean temperature warming above the depth of the 26~C isotherm （D26）, the deepening of D26, and the horizontal area expansion of SST above 26~C. Their contributions are 69.4%, 22.5% and 8.1%, respectively. Further, a suite of numerical experiments with an Ocean General Circulation Model （OGCM） is conducted to investigate the relative importance of wind stress and buoyancy forcing to the TCHP change under global warming. Results show that sea surface warming is the dominant forcing for the TCHP change, while wind stress and sea surface salinity change are secondary.

Etching characteristics of thin SiON films using a liquefied perfluorocarbon precursor of C_6F_(12)O with a low global warming potential

Perfluorocarbon gas is widely used in the semiconductor industry.However,perfluorocarbon has a negative effect on the global environment owing to its high global warming potential(GWP) value.An alternative solution is essential.Therefore,we evaluated the possibility of replacing conventional perfluorocarbon etching gases such as CHF_3 with C_6F_(12)O,which has a low GWP and is in a liquid state at room temperature.In this study,silicon oxynitride(SiON) films were plasma-etched using inductively coupled CF4+C_6F_(12)O+O_2 mixed plasmas.Subsequently,the etching characteristics of the film,such as etching rate,etching profile,selectivity over Si,and photoresist,were investigated.A double Langmuir probe was used and optical emission spectroscopy was performed for plasma diagnostics.In addition,a contact angle goniometer and x-ray photoelectron spectroscope were used to confirm the change in the surface properties of the etched SiON film surface.Consequently,the etching characteristics of the C_6F_(12)O mixed plasma exhibited a lower etching rate,higher SiON/Si selectivity,lower plasma damage,and more vertical etched profiles than the conventional CHF_3 mixed plasma.In addition,the C_6F_(12)O gas can be recovered in the liquid state,thereby decreasing global warming.These results confirmed that the C_6F_(12)O precursor can sufficiently replace the conventional etching gas.

Material flow analysis and global warming potential assessment of an industrial insect-based bioconversion plant using housefly larvae

The significant increase in the demand for biomass waste treatment after garbage classification has led to housefly larvae treatment becoming an attractive treatment option.It can provide a source of protein while treating biomass waste,which means that nutrients can be returned to the natural food chain.However,the performance of this technology in terms of its environmental impacts is still unclear,particularly with regards to global warming potential(GWP).This study used a life cycle assessment(LCA)approach to assess a housefly larvae treatment plant with a treatment capacity of 50 tons of biomass waste per day.The LCA results showed that the 95% confidence intervals for the GWP in summer and winter were determined to be 24.46-32.81 kg CO_(2) equivalent(CO_(2)-eq)/ton biomass waste and5.37-10.08 kg CO_(2)-eq/ton biomass waste,respectively.The greater GWP value in summer is due to the longer ventilation time and higher ventilation intensity in summer,which consumes more power.The main GWP contributions are from(1)electricity needs(accounting for 78.6% of emissions in summer and 70.2%in winter)and(2)product substitution by mature housefly larvae and compost(both summer and winter accounting for 96.8% of carbon reduction).

Negligible Warming Caused by Nord Stream Methane Leaks

Unanticipated sabotage of two underwater pipelines in the Baltic Sea(Nord Stream 1 and 2)happened on 26September 2022.Massive quantities of natural gas,primarily methane,were released into the atmosphere,which lasted for about one week.As a more powerful greenhouse gas than CO_(2),the potential climatic impact of methane is a global concern.Using multiple methods and datasets,a recent study reported a relatively accurate magnitude of the leaked methane at 0.22±0.03 million tons(Mt),which was lower than the initial estimate in the immediate aftermath of the event.Under an energy conservation framework used in IPCC AR6,we derived a negligible increase in global surface air temperature of 1.8×10^(-5)℃ in a 20-year time horizon caused by the methane leaks with an upper limit of 0.25 Mt.Although the resultant warming from this methane leak incident was minor,future carbon release from additional Earth system feedbacks,such as thawing permafrost,and its impact on the methane mitigation pathways of the Paris Agreement,warrants investigation.

AN ANALYSIS ON THE INFLUENCE OF GLOBAL CLIMATIC CHANGE UPON NATURAL ZONES AND AGRICULTURAL POTENTIALPRODUCTIVITY IN CHINA

According to climatic, hydrological, soil and vegetation data from671 stations in China, 12 temperate zones contains 45 natural regions areidentified. In this paper, methods like migration of crop distribution , potentialproductivity, and dynamic modelling are used to research changs of naturalzones and natural regions of eco-envirotunent.

Changes in the Tropical Cyclone Genesis Potential Index over the Western North Pacific in the SRES A2 Scenario

The Tropical Cyclone Genesis Potential Index （GPI） was employed to investigate possible impacts of global warming on tropical cyclone genesis over the western North Pacific （WNP）. The outputs of 20th century climate simulation by eighteen GCMs were used to evaluate the models＇ ability to reproduce tropical cyclone genesis via the GPI. The GCMs were found in general to reasonably reproduce the observed spatial distribution of genesis. Some of the models also showed ability in capturing observed temporal variation. Based on the evaluation, the models （CGCM3.1-T47 and IPSL-CM4） found to perform best when reproducing both spatial and temporal features were chosen to project future GPI. Results show that both of these models project an upward trend of the GPI under the SRES A2 scenario, however the rate of increase differs between them.

Tropical Cyclone Genesis Potential Index over the Western North Pacific Simulated by CMIP5 Models

Tropical cyclone （TC） genesis over the western North Pacific （WNP） is analyzed using 23 CMIP5 （Coupled Model Intercomparison Project Phase 5） models and reanalysis datasets. The models are evaluated according to TC genesis potential index （GPI）. The spatial and temporal variations of the GPI are first calculated using three atmospheric reanalysis datasets （ERA-Interim, NCEP/NCAR Reanalysis- 1, and NCEP/DOE Reanalysis-2）. Spatial distributions of July-October-mean TC frequency based on the GPI from ERA-interim are more consistent with observed ones derived from IBTrACS global TC data. So, the ERA-interim reanalysis dataset is used to examine the CMIP5 models in terms of reproducing GPI during the period 1982-2005. Although most models possess deficiencies in reproducing the spatial distribution of the GPI, their multi- model ensemble （MME） mean shows a reasonable climatological GPI pattern characterized by a high GPI zone along 20°N in the WNP. There was an upward trend of TC genesis frequency during 1982 to 1998, followed by a downward trend. Both MME results and reanalysis data can represent a robust increasing trend during 1982-1998, but the models cannot simulate the downward trend after 2000. Analysis based on future projection experiments shows that the GPI exhibits no significant change in the first half of the 21st century, and then starts to decrease at the end of the 21st century under the representative concentration pathway （RCP） 2.6 scenario. Under the RCP8.5 scenario, the GPI shows an increasing trend in the vicinity of 20°N, indicating more TCs could possibly be expected over the WNP under future global warming.

豫东沙土农区杨树-农作物复合生态系统中温室气体排放的研究

为了探讨农林复合系统农田土壤温室气体排放的贡献率,在豫东沙区杨树—农作物复合生态系统中选取了2种典型的防护林网密度——大网格BT(防护林间距1000 m×1000 m)、小网格ST(防护林间距200 m×200 m),并用周边5~10年生的人工纯林地作对照,采用静态箱—气相色谱法对不同防护林网密度的杨树—农作物复合生态系统中土壤温室气体(CO_(2)、N_(2)O、CH_(4))季节排放通量进行田间原位测定。结果表明:豫东农区农田土壤是CO_(2)、N_(2)O的排放源、CH_(4)的吸收汇。不同农林复合模式对土壤温室气体的排放或吸收的强度都有不同的特征,大网格、小网格、林地土壤CO_(2)日排放通量均在7月达到最大值,分别为1163.17、1005.91、923.53 mg/(m^(2)·h);大网格的土壤N_(2)O日排放通量在7月达到最大值,小网格和林地则在8月达到最大值,土壤N_(2)O排放通量为4.29~313.28μg/(m^(2)·h);3种模式下土壤CH_(4)的吸收峰值均在7月达到最大值,其中大网格的吸收峰值最大,为4.41 mg/(m^(2)·h)。不同农林复合经营模式通过影响土壤、空气温度和湿度等来影响农田土壤温室气体排放,其中增温干燥强化了土壤CO_(2)和N_(2)O排放源的特征,但同时也增加了土壤作为大气CH_(4)吸收汇的功能,大网格、小网格、林地的全球增温潜势(GWP)分别为1.50×10^(5)、1.03×10^(5)、0.885×10^(5)kg C/hm^(2),单位面积GWP值以林地的最小、大网格的最大。总的来看,适当增加防护林网密度有利于减少农林系统的增温潜能。

Radiative forcing and global warming potential of perfluorocarbons and sulfur hexafluoride

We developed two radiation parameterizations with different resolutions （17-band and 998-band） for perfluorocarbons （PFCs） and sulfur hexafluoride （SF6） using the updated High-resolution Transmission Molecular Absorption （HITRAN） 2004 database and the correlated k-distribution method. We analyzed the impacts of the two radiation schemes on heating rates. Then we studied their instantaneous radiative efficiency, stratospheric adjusted radiative efficiency, global warming potential （GWP）, and global temperature potential （GTP）, for both clear- and all-sky conditions using a high-resolution radiation scheme. We found that the stratosphere-adjusted radiative efficiencies of C2F6, CF4, and SF6 for the whole sky were 0.346, 0.098, and 0.680 W m^-2 ppbv^-1, respectively. Radiative forcing from the industrial revolution to 2005 was 0.001, 0.007, and 0.004 W m^-2, respectively; and was predicted to rise to 0.008, 0.036, and 0.037 W m^-2, respectively, by 2100, according to emission scenarios provided by the IPCC. The GWPs of C2F6, CF4, and SF6 are 17035, 7597, and 31298, respectively, for a time horizon of 100 years relative to CO2. Their GTPs of pulse and sustained emissions, GTPv and GTPs, are 22468, 10052, and 40935 and 16498, 7355, and 30341, respectively, for a 100-year time horizon.

Numerical analysis of the source-sink alternation of composite global warming potential of the paddy ecosystem in the Yangtze Delta

By coupling the biogeochemical model with plant ecological model, a model was established to reveal the principle of the composite global warming potential transformation in the paddy ecosystem. Validation of the model with the observed data indicated that the model can simulate both the crop growth processes and emissions of CH4 and N2O accurately. Some nu-merical analyses were made to identify the impacts of different fertilizer application on assimilation of CO2 and emissions of CH4 and N2O, and the transformation principle of the composite global warming potential. Based on the results of the numerical analysis, the source-sink alternation of composite global warming potential in the paddy ecosystem was discovered, and some new con-ceptions of fertilizer index such as maximum-sink fertilizer, zero-emission fertilizer are put forward in this paper. The fertilizer scheme for Yangtze Delta was proposed to provide the important scien-tific basis for a sustainable agriculture in this region.

Thermodynamic Performance and Flammability Studies of Hydrocarbon Based Low Global Warming Potential Refrigerant Mixtures

This paper presents a theoretical method to calculate the minimum inerting concentration(MIC)of binary and ternary blends(refrigerants)that are used in small refrigeration systems.MIC is the concentration of the dilutant which makes the flammable mixture into just non-flammable(at non-zero quenching potential).In this study,the refrigerant safety parameters such as flammability,Global Warming Potential(GWP)and performance(COP)are analyzed for twelve binary and thirteen ternary blends containing one flammable and two nonflammable(dilutant)components.Flammability investigation was carried out with the hydrocarbon refrigerants R290,R600,R600a each mixed with dilutants R227ea,R125,R245fa,R13I1 and R134a at different concentrations respectively.Two methods,thermal balance method(TBM)and modified thermal balanced method(MTBM),are used to estimate the MIC(which decides the flammable zone).Thirteen ternary blends were identified based on the MIC values estimated using MTBM.In the case of ternary blends,it was observed that the non-flammable zone is high for the compositions of the Mixture G,Mixture H and Mixture I.It was also estimated that the COPs of the proposed mixtures M22,M24,M25 and M27 are 4%greater than the COP of R134a(for the same operating conditions).Further,it was also understood that the corresponding GWP value is reduced by 90%to 97%for the mixtures(M21,M22,M24,M25 and M27)when compared to R134a(GWP=1300).Therefore,out of the thirteen proposed ternary mixtures(M15 to M27),the mixtures(M21,M22,M24,M25 and M27)are safe in terms of flammability,GWP and possess reasonable COP which can be a potential alternative refrigerant mixture to R134a in small refrigeration systems.

施用生物炭和秸秆还田对农田温室气体排放及增温潜势的影响

【目的】农业生态系统增温潜势是影响全球气候变化的重要部分。本研究通过田间试验明确施用生物炭和秸秆还田对农田增温潜势的影响,以期为减缓气候变化和农业废弃物资源化利用提供理论依据。【方法】在山东省桓台县农业生态系统试验站的冬小麦-夏玉米轮作农田中开展了3年田间定位试验,试验共设置4个处理:①对照(CK);②施用生物炭9.0t·hm^(-2)·a^(-1)(C);③全量秸秆还田(S);④秸秆还田配施9.0 t·hm^(-2)·a^(-1)生物炭(CS)。4个处理均施等量的氮磷钾化肥,其中氮肥为尿素,用量为200 kg·hm^(-2)·a^(-1),磷肥为过磷酸钙,用量为55 kg·hm^(-2)·a^(-1),钾肥为硫酸钾,用量为40 kg·hm^(-2)·a^(-1)。采用静态暗箱-气相色谱法测定各处理温室气体(CO_(2)、N_(2)O和CH_4)的排放通量并计算净全球增温潜势(NGWP)和温室气体排放强度(GHGI),分析连续施用生物炭和秸秆还田对农田温室气体排放及增温潜势的影响。【结果】(1)综合3年的温室气体排放情况,与CK处理相比,S和CS处理的年平均生态呼吸排放量(Re)分别增加了47.8%和67.9%(P<0.05);C处理的年平均N_(2)O累积排放量降低了20.3%(P<0.05),而S和CS处理的N_(2)O年平均累积排放量分别增加了23.6%和41.4%(P<0.05)。(2)与CK处理相比,C、S和CS处理的土壤有机碳年平均变化量(ΔSOC)均有显著增加,其中CS处理增幅最大,增加了150.6%(P<0.05)。与第1年相比,C、S和CS处理第3年的ΔSOC均有显著增加(P<0.05),分别增加了21.7%、20.8%和17.8%。各处理的NGWP和GHGI均存在显著差异,与CK相比,C、S和CS处理的年平均NGWP分别降低了163.5%、171.7%和273.0%(P<0.05),与第1年相比,C、S和CS处理第3年的NGWP均有显著降低(P<0.05),分别降低了73.4%、58.8%和54.7%。与CK相比,C、S和CS处理的年平均GHGI分别降低了236.2%、253.3%和388.9%(P<0.05),C、S和CS处理第3年的GHGI较第1年分别降低了126.3%、98.2%和108.6%(P<0.05)。就产量而言,C、S和CS处理的作物产量保持相对稳定,有轻微增长,但与CK相比无显著差异。【结论】与单施化肥相比,在施化肥的基础上添加生物炭、秸秆还田、秸秆还田配施生物炭的措施均能够在不影响作物产量的前提下抑制增温潜势,其中秸秆还田配施生物炭能够最大程度地降低农田增温潜势,因此秸秆还田配施生物炭是增加农田固碳、缓解气候变化的一项有效措施。

华北平原地区HCFC-142b排放清单建立及环境影响分析

选择华北平原地区作为研究对象,采用排放因子法建立该区域2000~2060年HCFC-142b排放清单,探讨了其空间分布特征,并对不同行业开展了排放结果的敏感性分析.结果显示,该地区2000~2019年HCFC-142b累计排放量为34.0kt.其中,江苏、山东和河南是排放量最大省份,累计排放量分别为595.1t、267.6t和196.5t.XPS泡沫排放最大,其次是ICR行业,两个行业对排放结果最敏感的因子分别是初始排放因子和设备废弃率.排放预测显示,在《蒙特利尔议定书》管控下,该地区2020~2060年的累计减排潜力为151.9kt(9.9kt CFC-11-eq;350.9mt CO_(2)-eq).

冬小麦-夏玉米Ⅱ夏花生周年种植的农田温室气体排放及碳足迹评价

为探究冬小麦-夏玉米Ⅱ夏花生周年种植模式对农田温室气体排放及碳足迹的影响,设置冬小麦-夏玉米、冬小麦-夏花生、冬小麦-夏玉米Ⅱ夏花生3种轮作种植方式;其中夏玉米Ⅱ夏花生间作设置3∶4,3∶6和6∶8三种行比。通过大田试验研究了周年农田温室气体排放和碳足迹特征。结果表明,夏玉米Ⅱ夏花生种植模式能够减少农田温室气体的排放,与玉米单作相比,土壤CO_(2)和N_(2)O的平均排放通量降幅分别为10.24%~18.75%和10.78%~23.93%、排放总量降幅分别为8.30%~19.12%和14.09%~26.81%。间作减少了后茬冬小麦(轮作模式下)的温室气体排放,间作处理的后茬冬小麦较玉米单作处理的后茬冬小麦土壤CO_(2)排放通量减少3.79%、排放总量减少3.84%;土壤N_(2)O排放通量减少16.80%、排放总量减少17.66%;土壤CH_(4)排放总量呈现“汇”现象。此外,单作玉米生产过程中碳足迹主要来源是氮肥,占总排放的49.13%;单作花生生产过程中碳足迹主要来源是氮肥和地膜,分别占总排放的23.77%和26.06%;间作模式下碳足迹主要来源是氮肥、柴油和地膜,分别占总排放的31.50%、16.74%、17.92%。间作模式增加了后茬小麦碳排放效率、降低了全球增温潜势和温室气体排放强度。综上,冬小麦-夏玉米Ⅱ夏花生(间作玉米花生行比3:6)周年种植模式能够减少农田碳排放与作物生产过程中的碳足迹,具有良好的生态效益。

生命周期评价方法在医药领域的应用现状与研究进展

生命周期评价(life cycle assessment,LCA)方法可以系统识别和评估不同产品与工艺之间的环境问题,确定污染物排放量并最大限度地减少产品和工艺过程中的环境影响。相比于基础大宗化工产品,医药化学品及中间体通常比较复杂,所带来的环境影响更大,通过生命周期评价可以量化分析医药领域中产品全生命周期过程造成的潜在环境影响,以支持医药领域“双碳”目标发展。本文简述了生命周期评价方法的四个步骤:目的和范围的确定,生命周期清单分析,生命周期影响评价和生命周期解释。并在此基础上,从药物生产、医疗器械、医疗服务三方面综述了生命周期评价在医药领域的应用现状和研究进展,指出了现有的医药生命周期评价研究所存在的一些问题,如研究相对较少、数据收集困难,尤其是药物中间体结构复杂、生命周期上游清单数据缺失,以及数据质量不高、生命周期影响评价方法不统一等。最后,针对未来医药领域生命周期评价发展提出相关建议。

种植模式协同秸秆管理对稻田温室气体排放的影响

在浙江省嘉善县选取1.3 hm^(2)稻田,设置节水旱管+秸秆还田/不还田与普通淹灌+秸秆还田/不还田2种种植模式4个处理组(以下简称节水还田、节水不还田、普通还田、普通不还田),采用静态箱-气相色谱法获取28批次336个稻田甲烷(CH_(4))和氧化亚氮(N_(2)O)排放数据,同时结合土壤颗粒有机碳(POC)等6个环境因子12个样品分析结果,探究种植模式协同秸秆管理对稻田温室气体排放特征的影响。结果显示:1)CH_(4)累计排放量依次为普通还田>普通不还田>节水还田>节水不还田,N_(2)O累计排放量为普通还田>节水不还田>节水还田>普通不还田。全球增温潜势(GWP)与温室气体排放强度(GHGI),普通还田最高,分别为7696.03 kg/hm^(2)(以CO_(2)计,全文同)、0.97 kg/kg;节水不还田最低,分别为2110.12 kg/hm^(2)、0.21 kg/kg。2)最小显著差异法分析结果表明,各处理组之间CH_(4)累计排放量存在显著差异。据Pearson相关性分析结果,CH_(4)累计排放量与POC含量呈极显著正相关(P<0.01),与微生物碳含量呈显著正相关(P<0.05);N_(2)O累计排放量则与硝态氮(NO_(3)^(-)-N)含量呈显著正相关(P<0.05),GWP、GHGI与POC含量呈极显著正相关(P<0.01)。3)种植模式与秸秆管理均对CH_(4)累计排放量有极显著影响(P<0.01),二者交互作用对CH_(4)累计排放量、N_(2)O累计排放量有显著影响(P<0.05)。研究表明,水稻节水旱管种植协同秸秆还田措施是一种气候友好型的高产经济种植模式,既可保证粮食安全,降低秸秆离田成本,对于减缓全球温室效应也具有积极作用。

填闲作物对烤烟生长和温室气体排放的影响

为了解填闲作物对烤烟生长和温室气体排放的影响,本研究以潮土烟田为研究对象,在冬季休闲期分别种植光叶紫花苕(Vicia villosa var.glabrescens)、小黑麦(×Triticale Wittmack)和油菜(Brassica napus),地上部分饲用,残茬还田,分析各处理间填闲作物及烤烟生物学产量、土壤CO_(2)和N_(2)O排放的差异。结果表明:(1)3种填闲作物处理烤烟总生物量和烟叶产量均显著高于对照,其中光叶紫花苕最高、油菜次之;(2)光叶紫花苕-烤烟、小黑麦-烤烟和油菜-烤烟土壤CO_(2)排放量分别略高于、显著高于和显著低于对照,土壤N_(2)O排放量均显著低于对照,其中油菜-烤烟差异最大;(3)烟田土壤CO_(2)的全球增温潜势远大于N_(2)O,光叶紫花苕、小黑麦和油菜处理土壤的全球增温潜势分别是对照的106.1%、116.2%和78.1%。综上所述,黄淮烟区潮土烟田油菜-烤烟种植模式既能提高烤烟收益又可降低烟田土壤的全球增温潜势,光叶紫花苕-烤烟在不显著提高烟田土壤全球增温潜势的同时可更大幅度提高烤烟收益,因此,可因地制宜发展油菜-烤烟或光叶紫花苕-烤烟等种植模式。