农田系统氨挥发与温室气体排放研究进展

通过对国内外有关农田系统氨挥发与温室气体排放的机理及其影响因子等进行综述,发现已有研究对植物体是否挥发损失N2及N2O存在争议.指出今后可以从栽培模式、氨挥发与温室气体排放的规律及影响因子等方面人手进行研究,以期为最佳栽培模式的管理提供理论依据.     

农业生态系统研究进展

综述了农业生态系统研究的由来与发展，提出了随着研究的深入，对概念，性质认识的深化和研究方向的转换，对农业生态系统近期研究领域及未来研究趋向作了概括，指明了今后研究的目标与方向。     

覆盖对水稻田温室气体排放效应的影响

农田覆盖作为一种重要的农艺生产措施,已被广泛应用于各种农业生产活动中。为了定量分析覆盖条件下农田温室气体的排放效应、改善农田覆盖模式和减少农业温室气体排放,采用Meta分析方法分析了覆盖对水稻田温室气体排放的影响,并对其主要影响因素进行解析。结果表明,与不覆盖相比,覆盖水稻田CO₂排放量平均增加21.9%(置信区间2.6%～44.8%),N₂O排放量平均减少43.9%(置信区间32.3%～53.5%),CH₄排放量平均减少58.5%(置信区间50.8%～65.0%)。N₂O排放量随施氮量的增加呈降低趋势,覆盖水稻田的平均减排率为湖南和江苏高于重庆和湖北;与一次性基施、地膜覆盖、部分地面覆盖、垄作和连作相比,基肥+追肥、秸秆覆盖、全地面覆盖、平作和轮作更有利于提高覆盖水稻田的N₂O减排率。CH₄排放量随施氮量的增加呈增加趋势,覆盖水稻田的平均减排率表现为四川>江苏>湖北>湖南>重庆;与基肥+追肥、秸秆覆盖、全地面覆盖、垄作和轮作相比,...     

作物秸秆还田对稻田温室气体排放效应的研究进展

秸秆还田具有改善土壤结构、培肥土壤等积极作用,是中国水稻生产中的一项重要管理措施,但秸秆还田也会对稻田温室气体排放产生重要影响.总结了小麦、水稻、玉米等秸秆还田对稻田温室气体排放的影响、机制以及秸秆还田后相关的减排措施等方面的研究进展,并提出了未来加强秸秆还田和稻田温室气体排放关系的研究方向,以期为秸秆资源高效利用与稻...     

秸秆还田对稻田土壤和温室气体排放的影响

秸秆还田作为农业生产中的重要环节,具有固碳、促进养分元素循环、减少化肥施用、维持土壤肥力的积极作用。本文概述了作物秸秆的利用现状、秸秆还田对稻田土壤理化性质及温室气体排放的影响,并对秸秆还田研究进行了展望。     

海南岛橡胶林生态系统碳通量及其影响因子研究

以位于海南岛西北部儋州地区的橡胶林为研究对象,采用涡度相关技术进行长期CO2通量观测,获得海南岛橡胶林生态系统碳通量的动态特征,并分析其对各影响因子的响应情况。结果表明:(1)橡胶林生态系统净碳交换量(NEE)日动态均为"U"型曲线,白天均为碳吸收(NEE为负值),夜间均为碳排放(NEE为正值);全年各月除2月外,NEE月总值均为负值,吸收碳,雨季4~10月各月NEE值均较大,旱季1~3月、11~12月,各月NEE值均较小;橡胶林年固碳能力强大,超过11.0 t C/(hm2·a)。(2)橡胶林生态系统NEE与光合有效辐射(PAR)、冠层内大气平均温度(Ta)、地下5 cm土壤温度(T_-5 cm)和饱和水汽压差(VPD)及地下5 cm土壤含水量(VWC_-5 cm)等均负相关,但影响强度不同,其中PAR影响最为显著;另外NEE还与橡胶林本身林分状况及周围大气环境CO2浓度等相关。     

炭基有机肥对小麦产量及麦季农田温室气体排放的影响

为减少生物质炭在农田应用的农事操作工序,探讨生物质炭与畜禽粪便混合堆肥产品——炭基有机肥对小麦产量及麦季农田温室气体排放的影响,试验以施用炭基有机肥为处理,以施用商品有机肥与不施有机肥为对照,共计3个处理,探讨了炭基有机肥对小麦产量、甲烷(CH_4)与氧化亚氮(N_2O)排放通量及单位产量的全球增温潜势(GWP)的影响。结果表明:炭基有机肥有促进小麦产量提高的趋势,但与商品有机肥、不施有机肥相对而言,产量差异未达显著水平;炭基有机肥处理的小麦千粒质量显著大于商品有机肥及不施有机肥处理;增施有机肥处理的麦田土壤甲烷排放总量低于不施有机肥处理,而氧化亚氮的排放总量则高于不施有机肥处理;与商品有机肥相比,施用炭基有机肥处理的全球增温潜势降低了36.48%、单位产量的GWP下降了37.3%,但不同处理之间差异均未达显著水平。     

氮肥运筹和秸秆还田对麦季土壤温室气体排放的影响

为了解氮肥运筹和秸秆还田对麦田土壤温室气体排放的影响,在秸秆还田条件下设置基肥∶壮蘖肥∶拔节肥∶孕穗肥为3∶1∶3∶3(N1)、5∶1∶2∶2(N2)、7∶1∶2∶0(N3)三个氮肥运筹方式,在秸秆不还田条件下设置5∶1∶2∶2一个氮肥运筹方式(N4),采用静态暗箱-气相色谱法对不同处理下麦田土壤排放的二氧化碳(CO2)、甲烷(CH4)和氧化亚氮(N2O)进行观测,测定小麦籽粒产量,估算土壤温室气体排放强度(GHGI)和麦季全球增温潜势(GWP)。结果表明,与秸秆不还田相比,秸秆还田显著促进了麦季CH4和CO2的排放,显著降低了N2O的排放,显著提高了麦季GWP。秸秆还田条件下,不同氮肥运筹方式间CH4、CO2累积排放量和GWP差异不显著,但N3处理显著提高了N2O累积排放量,分别较N1、N2处理提高61.22%、51.92%。N1、N2处理的GHGI最低,分别较N4处理降低41.27%和39.67%,N3处理的GHGI较N4处理增加3.30%。因此,麦季秸秆还田下采用3∶1∶3∶3和5∶1∶2∶2氮肥运筹方式有显著地增产与综合减排作用,是低碳生产的合理施肥措施。     

生物炭与氮肥施用对双季稻田温室气体排放的影响

以我国南方双季稻田为研究对象,旨在探究生物炭与氮肥施用对稻田温室气体排放的影响.试验共设置5个处理,分别为不施氮肥不施生物炭(N0B0)、单施40 t/hm2生物炭(N0B2)、单施氮肥(N1B0)、氮肥配施20 t/hm2生物炭(N1B1)、氮肥配施40 t/hm2生物炭(N1B2).采用静态暗箱-气象色谱法连续监测...     

秸秆还田对水稻生长发育和稻田温室气体排放的影响

秸秆是一种传统的能源物质,营养丰富,秸秆还田可培肥地力,增加作物产量。本文综述了秸秆及其制成的有机物料还田对水稻产量和稻米品质的影响及其生物学机制、秸秆还田对培肥土壤的作用和稻田温室气体排放的影响,讨论了秸秆还田存在的问题和今后研究的重点。     

Influence of irrigation frequency on greenhouse gases emission from a paddy soil

Water management is known to be a key factor on methane (CH₄), carbon dioxide (CO₂), and nitrous oxide (N₂O) emissions from paddy soils. A field experiment was conducted to study the effect of continuous irrigation (CI) and intermittent irrigation (II) on these emissions. Methane, CO₂, and N₂O emissions from a paddy soil were sampled weekly using a semi-static closed chamber and quantified with the photoacoustic technique from May to November 2011 in Amposta (Ebro Delta, NE Spain). Intermittent irrigation of rice paddies significantly stimulated (N₂O + N₂)–N emission, whereas no substantial N₂O emission was observed when the soil was re-wetted after the dry phase. The cumulative emission of (N₂O + N₂)–N was significantly larger from the II plots (0.73 kg N₂O–N ha^?1 season^–1, P < 0.05) than from the CI plots (?1.40 kg N₂O–N ha^?1 season^?1). Draining prior to harvesting increased N₂O emissions. Draining and flooding cycles controlled CO₂ emission. The cumulative CO₂ emission from II was 8416.35 kg CO₂ ha^?1 season^?1, significantly larger than that from CI (6045.26 kg CO₂ ha^?1 season^?1, P < 0.05). Lower CH₄ emission due to water drainage increased CO₂ emissions. The soil acted as a sink of CH₄ for both types of irrigation. Neither N₂O–N nor CH₄ emissions were affected by soil temperature. Global warming potential was the highest in II (4738.39 kg CO₂ ha^?1) and the lowest in CI (3463.41 kg CO₂ ha^?1). These findings suggest that CI can significantly mitigate the integrative greenhouse effect caused by CH₄ and N₂O from paddy fields while ensuring the highest rice yield.     

作物覆膜温室效应研究进展

作物覆膜栽培技术在我国已经发展多年,极大地推动了作物生长发育的研究及其在生产上的应用。研究发现,覆膜能使土温提高1～5℃,使土壤含水量增加0.5%～50%,显著增加土壤微生物的数量;还能促进氮、碳等元素的循环,加速有机质及其他养分元素的矿化;加快作物的生长,影响干物质的积累,提高作物产量。研究表明,适宜的地膜覆盖创造了有利于作物生长的环境,但长期覆膜会造成土壤肥力下降。     

Greenhouse gases emission from paddy soil during the fallow season with and without winter flooding in central Japan

Many papers on measurements of greenhouse gases (GHGs) emission in rice paddies during a rice cropping season have been published. During a non-cropping season between Nov. and Apr., we investigated direct and indirect GHGs emissions in rice paddies. The indirect GHGs emission was evaluated as the amount of dissolved gases leaching from the paddy fields. Water management practices for the experiment were (1) continuous flooding (CF) and (2) non-flooding (NF). Although the direct CO₂ emission in the CF treatment was remained nearly zero during the non-cropping period, direct CO₂ emission in the NF treatment was continuously observed throughout the non-cropping period. The concentration of dissolved N₂O in the NF treatment was below the detection limit of the instrument during the non-cropping period except immediately after the flooding and before the drainage. The concentration of dissolved N₂O kept approximately 2 µg L^?1 during the non-cropping period in the CF treatment. The direct CH₄ emission and dissolved CH₄ were not observed during the non-cropping period. Total gas emission in the NF treatment was 10 times as large as that in the CF treatment. Direct CO₂ emission accounted for more than 90 % of the total emission in both treatments.     

Mitigation of greenhouse gas emission with system of rice intensification in the Indo-Gangetic Plains

System of rice intensification (SRI) is an alternate method of conventional puddled, transplanted, and continuously flooded rice cultivation for higher yield, water saving, and increased farmer’s income. The SRI may also have considerable impact on greenhouse gas emission because of difference in planting, water and nutrient management practices. A field experiment was conducted with three planting methods: conventional puddled transplanted rice (TPR), conventional SRI with 12-days-old seedling (SRI) and modified SRI with 18-days-old seedling (MSRI) to study their effect on methane and nitrous oxide emission. Seasonal integrated flux (SIF) for methane was highest in the conventional method (22.59 kg ha^?1) and lowest in MSRI (8.16 kg ha^?1). Methane emissions with SRI and MSRI decreased by 61.1 and 64 %, respectively, compared to the TPR method. Cumulative N₂O–N emission was 0.69, 0.90, and 0.89 kg ha^?1 from the TPR, SRI, and MSRI planting methods, respectively. An average of 22.5 % increase in N₂O–N emission over the TPR method was observed in the SRI and MSRI methods. The global warming potential (GWP), however, reduced by 28 % in SRI and 30 % in MSRI over the TPR method. A 36 % of water saving was observed with both SRI and MSRI methods. Grain yield in the SRI and MSRI methods decreased by 4.42 and 2.2 %, respectively, compared to the TPR method. Carbon efficiency ratio was highest in the MSRI and lowest in the TPR method. This study revealed that the SRI and MSRI methods were effective in reducing GWP and saving water without yield penalty in rice.     

Dry direct-seeding of rice for mitigating greenhouse gas emission: field experimentation and simulation

Conventional puddled transplanted rice (TPR) is a major source of greenhouse gas (GHG), particularly methane, causing global warming. Direct-seeded rice (DSR) is a feasible alternative to mitigate methane emission, besides saving water and labor. A 2-year field experiment was carried out to quantify GHG mitigation and water- and labor-saving potentials of the DSR crop compared to TPR in three villages in Jalandhar district of Punjab, India. The InfoRCT simulation model was used to calculate the emission of CO₂ besides CH₄ and N₂O in different districts of Punjab, India. Total global warming potential (GWP) in transplanted rice in various districts of Punjab ranged from 2.0 to 4.6 t CO₂ eq. ha^?1 and in the DSR it ranged from 1.3 to 2.9 t CO₂ eq. ha^?1. Extrapolation analysis showed that if the entire area under TPR in the state is converted to DSR, the GWP will be reduced by 33 %, and if 50 % area is converted to DSR the GWP will be reduced by 16.6 % of the current emission. The DSR crop saved 3–4 irrigations compared to the transplanted rice without any yield penalty. Human labor use also reduced to 45 % and tractor use to 58 % in the DSR compared to TPR.     

Rice-related greenhouse gases in Japan, variations in scale and time and significance for the Kyoto Protocol

The contribution of rice production to the three major greenhouse gases CO₂, CH₄ and N₂O in 1990, the base year of the Kyoto protocol is investigated for Japan. For the CO₂ assessment, we use a top-down life cycle approach, CH₄ is assessed using the Japanese GHG emission inventory and N₂O is assessed according to the ratio of rice area divided by the total area of agricultural soils. In total, 1.6% of greenhouse gas (GHG) emissions in 1990 originated from rice production. Next, we assess regional variations in nine rice-producing regions, based on the CO₂ data of 1990. General trends in rice production from 1960 to 2000 and data from the Japanese GHG emission inventory since 1990 are used to assess variations in time. The rice-related GHG emissions decreased to 1.05% of the total GHG emissions in 2001 and will be less than half the 1990 level in 2012, mainly due to the decrease in rice production. Contrary to the trend in GHG emissions of rice, overall GHG emissions increased as rice production fulfils important roles, in mitigating global warming and in adapting to changing climates. The protection of rice production is required to counter the increase of GHG emissions in transportation, waste and domestic sectors and to minimize problems related to landscape, water and natural hazard management.     

益阳市生态农业开发的问题与对策

基于益阳市生态农业发展存在的问题,提出了提高认识、加强领导,抓好生态技术的推广与培训,强化社会化服务,加大资金投入力度,治理农业自身污染,建立生态农业生产基地等对策。     

烟草抗寒性研究进展

概述了烟草种子发芽期和苗期抗寒性研究的最新进展,在此基础上认为,对烟草抗寒性研究应将低温胁迫与旱、涝、盐碱等其他因素相结合进行研究,利用内源低温诱导蛋白和外源化学物质调控技术来提高烟草的抗寒能力也是未来研究的可行选择。     

棉花杂种优势利用的研究进展

本文分析了我国棉花杂种优势的利用途径、预测方法和亲本组配的现状，并提出今后我国棉花杂种优势利用的发展方向。     

Impact of grass silage quality on greenhouse gas emissions from dairy and beef production

High‐quality grass silages may represent a mitigation option by reducing enteric methane production and by increasing productivity, thus reducing greenhouse gas emissions per kg of product (emission intensity). Two previous studies found considerable effects of three different silage qualities cut at different maturity stages (very early [H1], early [H2] and normal [H3]) offered ad libitum with various levels of concentrate supplementation, on animal performances of growing/finishing bulls and dairy cows in early lactation, indicating that emission intensities may also vary. Based on results from these previous studies, the aim of this study was to estimate emission intensities for milk and beef carcasses for the included combinations of silage qualities and concentrate levels, by using the farm‐scale model HolosNor. The emissions intensities were lowest for the H1 silage, and highest for the H3 silage, independent of concentrate levels for both milk and beef. Thus, increasing concentrate levels did not compensate for lower grass silage quality. Improvements in silage quality from H3 silage to H2 is realistic and has the potential to reduce emission intensities with approximately 10% while keeping the milk yield per cow constant and reducing the use of concentrates considerably. For beef production, the potential is even larger, with a reduction in emission intensity of approximately 17%. We conclude that improving grass silage quality may be a mitigation option that will also reduce the dependence on concentrates.