耕作方式对双季稻田土壤剖面CH_4和N_2O分布特征的影响

【目的】探明双季稻稻田土壤剖面CH_4和N_2O的时空分布特征,有利于揭示农艺措施对稻田土壤温室气体产生和排放过程的作用机制。【方法】通过小区试验,研究了旋耕(RT)和免耕(NT)在不同培肥措施[不施肥(CK)、仅施化肥(F)、化肥+秸秆还田(FS)]下对双季稻主要生育期田面水和土壤剖面CH_4和N_2O分布特征的影响。【结果】早晚稻季田面水CH_4浓度显著低于土壤剖面CH_4浓度;而田面水N_2O浓度高于土壤剖面N_2O浓度。土壤剖面CH_4浓度随深度增加而下降;而N_2O浓度在土壤剖面中无显著变化。耕作方式对土壤剖面CH_4和N_2O浓度存在显著效应。与NT相比,RT显著增加了土壤剖面CH_4浓度,尤其是0-5 cm和5-10 cm土层;而在部分生育期显著降低土壤剖面N_2O浓度。早晚稻季CH_4净排放通量与上层土壤CH_4浓度相关性高于下层土壤和田面水。表层土壤是影响早稻季N_2O排放的主要因素,而中下层土壤是影响晚稻季N_2O排放的主要因素。【结论】双季稻田土壤剖面CH_4和N_2O具有明显的时空变化特征,而耕作方式对其浓度具有显著影响。     

低温室气体排放水稻品种筛选的初步研究

水稻品种是影响稻田温室气体排放的重要因素。高产低甲烷水稻品种的种植是减排稻田温室气体的潜在的重要措施。通过盆栽试验研究不同水稻品种的温室气体排放,结果表明,稻田排放的温室气体主要是甲烷,所排氧化亚氮增温潜势约为甲烷的1/60;不同水稻品种温室气体排放量差异显著;早稻品种选用陆两优996、晚稻品种选用金优139可显著减少温室气体排放。     

生物质炭输入对稻田土壤理化特性和温室气体排放及水稻产量影响研究进展

水稻是我国最主要的粮食作物，稻田也是温室气体甲烷和氧化亚氮的主要排放源。生物质炭因其具有较强的稳定性、吸附性和pH值高等特性，在改良土壤、提高作物产量等领域得到广泛应用。同时，生物质炭能够对稻田土壤微生物产生影响，直接或间接影响稻田温室气体的排放。本文总结了生物质炭对稻田土壤理化特性、温室气体排放及水稻产量的影响，提出了未来的研究方向，以期为水稻的高效生产及稻田温室气体减排提供理论与实践依据。     

硝化抑制剂双氰胺施用对水稻产量和温室气体排放的影响

为探究施用硝化抑制剂双氰胺对水稻产量和温室气体排放的影响,以常规粳稻品种南粳9108为供试材料进行盆栽试验,设置常规氮肥(CK)和常规氮肥配施硝化抑制剂双氰胺(DCD)2个处理。采用静态箱-气相色谱法连续监测稻田温室气体排放动态变化。结果表明,与CK相比,DCD显著提高了水稻产量(15.1%)和地上部生物量(28.4%),并且显著降低了稻田甲烷(CH₄)累积排放量(22.2%)、氧化亚氮(N₂O)累积排放量(56.0%)、综合温室效应(GWP)(24.4%)和温室气体排放强度(GHGI)(31.7%)。可见,常规氮肥配施硝化抑制剂双氰胺可以协同实现水稻丰产和稻田温室气体减排。     

农业生态系统温室气体排放研究进展

农业生态系统排放中主要的温室气体有二氧化碳（CO2）、氧化亚氮（N2O）、甲烷（CH4）。温度、水分、肥料、植被、光照、耕作制度和气候因子等影响着农业生态系统温室气体的排放量。通过静态箱法和动态箱法等,可以估算农业生态系统温室气体呼吸通量及总量。     

施氮水平对不同株型水稻品种N_2O排放通量的影响

以穗型直立的紧凑型水稻品种沈农07425和穗型弯曲的松散型水稻品种秋光为材料,在不同施氮水平下研究两种株型水稻品种的N_2O排放通量。结果表明,不同株型品种间N_2O排放通量差异显著,紧凑型沈农07425的N_2O排放通量远小于松散型秋光。不同株型品种N_2O排放通量随施氮量的变化存在差异。沈农07425的N_2O排放通量随着施氮量提高而增加,高氮处理下N_2O排放通量最大,秋光的N_2O排放通量则在中氮处理下达到最大值。     

稻田干湿交替过程生理生态效应研究综述

稻田干湿交替通过调节水稻生理活性特别是根系活性提高水稻产量,同时对减少温室气体排放,提高水分利用率,改善土壤通气状况,调节田间小气候有重要作用,是实现节水高产的重要技术措施。综述了稻田干湿交替灌溉的生理生态基础及其对水稻植株地上部分和根系生理特性、产量和品质、温室气体排放及土壤碳、氮矿化等的影响,并对稻田干湿交替实施中存在的问题及研究中应当关注的问题进行了探讨,以期为农业的可持续发展提供参考。     

水稻低碳生产研究进展

 稻田是甲烷(methane,CH4)和氧化亚氮(nitrous oxide,N2O)的重要发生源。稻田中CH4和N2O的产生、消耗以及传输过程受稻田土壤类型、水分条件、肥料种类、施肥量及方法、耕作模式和制度、水稻品种等多种因素影响。CH4和N2O具有不同的排放特性,很多研究结果表明,水稻生长期间的中期排水烤田、后期干湿交替能显著降低CH4排放量,但同时也可能促进N2O的排放,因此,如何同时减少CH4和N2O的排放量是实现稻田低碳生产的关键要素;另一方面,稻田土壤的碳固定也是使稻田系统从源转变成汇的关键技术。从水稻生产过程中CH4排放、N2O排放、稻田土壤有机碳动态、减排措施四个方面综述了近年来水稻低碳生产相关研究状况,重点总结了国内外有关影响稻田CH4和N2O排放的关键影响因素、增加稻田土壤有机质含量的主要措施以及各种减排措施的全球增温潜势评价研究,并对水稻低碳生产研究作了展望。     

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....     

江汉平原不同类型“一种两收”水稻品种对稻田CH4和N2O排放的影响

为了探讨多年生稻和再生稻生产模式对稻田温室气体排放的影响，为构建丰产减排的稻作模式提供依据，于2021年在湖北荆州以再生稻品种丰两优香1号、虾稻1号和多年生稻品种多年生稻23、云大25为研究对象开展试验，分析江汉平原多年生稻与再生稻的稻田CH₄、N₂O排放差异。结果表明，多年生稻和再生稻的CH₄排放规律基本一致，主要集中在头季齐穗期和再生季齐穗期；再生稻和多年生稻的N₂O排放趋势也基本一致，在头季施基肥和促芽肥至提苗肥期间出现N₂O排放。与再生稻相比，多年生稻头季、再生季和全生育期的CH₄排放分别增加了213.0%、55.8%和156.9%;多年生稻全生育期N₂O排放量与再生稻差异不显著，头季N₂O平均排放量较再生稻高13.7%,再生季却低40.4%。多年生稻的全球增温潜势和单位稻谷产量温室气体排放强度分别较再生稻高139.3%和650.0%。综合分析，再生稻丰两优香1号具有较高的稻谷产量和较低的温室气体排放，更...     

Effect of water management on greenhouse gas emissions and microbial properties of paddy soils in Japan and Indonesia

This research aims at elucidating the greenhouse gas emissions and its related soil microbial properties in continuously flooded or intermittently drained paddy soils in Japan and Indonesia. The study in Japan comprises alluvial soil and peat, cultivated to rice variety Nipponbare, while in Indonesia comprised alluvial soil cultivated to rice variety Siam Pandak. Intermittent drainage was performed to half number of the plot in 6 days interval, starting at tillering or heading stage of rice, while the other half number of plot was kept flooded as control. The experiments were carried out to follow the randomized block design with three replications. Gas samples were taken in weekly basis, except during the treatments (i.e., every 2 days interval) and analyzed for methane (CH₄) and nitrous oxide (N₂O) concentrations. Soil samples were and analyzed for the population of methanogenic bacteria, denitrifiers, methane production and consumption potentials, and methanogenic substrate. Plant growth parameters were also observed. The results showed that intermittent drainage significantly reduced greenhouse gas emission from paddy soil of Indonesia and Japan without significant changes in soil microbial population. The reductions of greenhouse emission from Japanese peaty and alluvial paddy soil due to intermittent drained were about 32 and 37%, respectively. Meanwhile, the reductions in greenhouse gas emission from alluvial soil of Indonesia due to intermittent drainage were very similar to that of in Japan, i.e., average about 37%. This suggests that intermittent drainage can be an appropriate technology option to reduce the greenhouse gas emission from paddy soil in Japan and Indonesia.     

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稻田CH₄与N₂O排放情况,分析生物炭施用对稻田CH₄与N₂O累积排放量、综合温室效应（GWP）、周年水稻产量、温室气体排放强度（GHGI）的影响。结果表明,在施氮或不施氮条件下,施用生物炭均显著降低稻田CH₄排放量,显著增加N₂O累积排放量。与N1B0处理相比,N1B1与N1B2处理CH₄累积排放量分别下降32.43%和41.0%,N₂O累积排放量分别增加109.93%和106.54%。各处理综合温室效应由大到小依次为N1B0> N0B0> N0B2> N1B1> N1B2。晚稻收获后,土壤pH值、总炭与C/N随生物炭施用量增加呈递增趋势,且N1B2处理较N1B0处理显著增加。综上所述,与单施氮肥和单施生物炭相比,生物炭与氮肥配施更有利于南方双季稻田固碳减排,其中,氮肥配施40 t/hm²生物炭处理效果最佳。本研究为生物炭运用于缓解稻田温室效应提供了参考。     

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。     

Changes in Grain Yield of Rice and Emission of Greenhouse Gases from Paddy Fields after Application of Organic Fertilizers Made from Maize Straw

A field experiment was conducted at the farm of Yangzhou University, Yangzhou, China, to study the effects of organic fertilizers made from maize straw on rice grain yield and the emission of greenhouse gases. Four organic fertilizer treatments were as follows： maize straw （MS）, compost made from maize straw （MC）, methane-generating maize residue （MR）, and black carbon made from maize straw （BC）. These organic fertilizers were applied separately to paddy fields before rice transplanting. No organic fertilizer was applied to the control （CK）. The effects of each organic fertilizer on rice grain yield and emission of greenhouse gases were investigated under two conditions, namely, no nitrogen （N） application （ON） and site-specific N management （SSNM）. Rice grain yields were significantly higher in the MS, MC and MR treatments than those in CK under either ON or SSNM. The MS treatment resulted in the highest grain yield and agronomic N use efficiency. However, no significant difference was observed for these parameters between the BC treatment and CK. The changes in the emissions of methane （CH4） carbon dioxide （CO2）, or nitrous oxide （N20） from the fields were similar among all organic fertilizer treatments during the entire rice growing season. The application of each organic fertilizer significantly increased the emission of each greenhouse gas （except N20 emission in the BC treatment） and global warming potential （GWP）. Emissions of all the greenhouse gases and GWP increased under the same organic fertilizer treatment in the presence of N fertilizer, whereas GWP per unit grain yield decreased. The results indicate that the application of organic fertilizer （MS, MC or MR） could increase grain yield, but also could enhance the emissions of greenhouse gases from paddy fields. High grain yield and environmental efficiency could be achieved by applying SSNM with MR.     

Implications of climate change for grassland in Europe: impacts, adaptations and mitigation options: a review

Climate change associated with greenhouse gas (GHG) emissions may have important implications for Europe's grasslands. Projected scenarios indicate that increased temperatures and CO₂ concentrations have the potential to increase herbage growth and to favour legumes more than grasses, but changes in seasonal precipitation would reduce these benefits particularly in areas with low summer rainfall. Further implications for grasslands may arise from increased frequency of droughts, storms and other extreme events. Potential farm-scale adaptive responses to climate change are identified. Grassland agriculture also contributes to GHG emissions, particularly methane and nitrous oxide, and management of grassland affects net carbon balances and carbon sequestration. Management options are identified for mitigating grassland's contribution to GHG emissions which need to be developed in a holistic way that also considers other pressures.     

Forage legumes in grass pastures in tropical Brazil and likely impacts on greenhouse gas emissions: A review

Beef cattle producers seldom use fertilizers for their pastures in tropical regions of Brazil. Slowly, this is changing but because of the need for repeated applications, N fertilizer is rarely applied. The introduction of a forage legume is an appropriate solution for this problem, but until recently adoption has been very low as the legumes generally have not persisted in the sward. We report research on how grazing management can affect the persistence of stoloniferous legumes in pastures of Brachiaria spp. and the problems of establishing and maintaining crown-forming legumes such as Stylosanthes spp. With suitable management, milk or bovine carcass yields can be equal or greater from mixed than from grass-alone pastures fertilized with 120 or 150 kg Nha^-1 year⁻¹. In addition to savings in CO₂ emissions from fossil fuels for the production and distribution of N fertilizers, nitrous oxide emissions from cattle excreta and legume residues are lower than those from N-fertilized brachiaria grass monocultures. Other studies indicate that enteric methane emissions from cattle may be mitigated when forage legumes are included in their diet. The use of forage legumes in mixed pastures for tropical regions is emerging as a feasible strategy to keep meat and milk production at acceptable levels with reduced greenhouse gas emission rates.     

我国典型茶区化学氮肥施用与生产运输过程的温室气体排放量估算

基于相关统计数据和文献调研方法,估算了我国14个典型茶区中化学氮肥施用、生产及运输过程中的温室气体排放量。结果表明,化学氮肥施用导致的土壤N₂O直接排放和生产过程中的温室气体排放是茶园化学氮肥消费带来的温室气体主要排放源;14个典型茶区消费的化学氮肥产生的温室气体排放量(以CO₂排放当量计算)为16.81~344.80万t·a^-1,其中贵州、云南、湖北和四川4省的茶园消费的化学氮肥带来的温室气体排放量较高,均超过200万t·a^-1,占全部区域温室气体排放量的59.98%;单位面积温室气体排放量为3.22~9.76 t·hm^-2·a^-1,单位产量温室气体排放量为2.10~12.96 t·t^-1·a^-1、单位产值温室气体排放量0.39~1.90 t·万元^-1·a^-1;总体而言,贵州、云南、湖北、湖南和四川5省的茶园消费的化学氮肥带来的温室气体排放量、单位面积温室气体排放量、单位产量温室气体排放量和单位产值温室气体排放量较高,福建、河南省及重庆市3个茶区相对较低。在茶园化学氮肥施用量控制为300 kg·hm^-2和450 kg·hm^-2两种情景下,茶园生态系统温室气体减排总量为617.07万t·a^-1和228.94万t·a^-1,减排潜力为34.12%和12.66%,减排潜力较大的区域主要有湖北、四川、贵州、湖南和江西等5省。     

Application of Rice Husk Biochar for Achieving Sustainable Agriculture and Environment

This paper critically reviewed the current knowledge and challenges of rice husk biochar(RHB) production and its effects on soil properties, plant growth, immobilization of heavy metals, reduction of nutrient leaching and mitigation of greenhouse gas emissions. The characteristics of RHBs produced at various pyrolysis temperatures were discussed and compared to biochars derived from other agroindustrial wastes. RHBs produced at higher pyrolysis temperatures show lower hydrogen/carbon ratio, which suggests the presence of higher aromatic carbon compounds. The increase of pyrolysis temperature also results in production of RHBs with higher ash content, lower yield and higher surface area. RHB usually has higher silicon and ash contents and lower carbon content compared to biochars derived from other feedstocks at the same pyrolysis conditions. Although it depends on soil type, RHB application can improve soil organic carbon content, cation exchange capacity, available K concentration, bulk density and microbial activity. The effect of RHB on soil aggregation mainly depends on soil texture. The growth of different crops is also enhanced by application of RHB. RHB addition to soil can immobilize heavy metals and herbicides and reduce their bioavailability. RHB application shows a significant capacity in reduction of nitrate leaching, although its magnitude depends on the biochar application rate and soil biogeochemical characteristics. Use of RHB, especially in paddy fields, shows a promising mitigation effect on greenhouse gas(CH_4, CO_2 and N_2 O) emissions. Although RHB characteristics are also related to other factors such as pyrolysis heating rate and residence time, its performance for specific applications(e.g. carbon sequestration, p H amendment) can be manipulated by adjusting the pyrolysis temperature. More research is needed on long-term field applications of RHB to fully understand the advantages and disadvantages of RHB as a soil amendment.     

Policy measures to promote mid-summer drainage in paddy fields for a reduction in methane gas emissions: the application of a dynamic,spatial computable general equilibrium model

Rice production is affected by climate change, while climate change is simultaneously accelerated by methane gas (CH₄) emissions from paddy fields. The rice sector must take suitable mitigation measures, such as prolonging mid-summer drainage (MSD) before the rice flowering period. To propose a mitigation policy, this study aims to demonstrate the environmental and economic effects of MSD in Japanese paddy fields by using a dynamic, spatial computable general equilibrium (CGE) model and crop model; the study also considers environmental subsidies with a carbon tax scheme to promote MSD measures. The results demonstrate that climate change under the 8.5 representative concentration pathway (RCP) scenario will reduce rice prices and rice farmers’ nominal income due to bumper harvests until the 2050s. Promoting MSD in paddy fields can prevent a decrease in farmers’ nominal income and effectively reduce CH₄ emissions if all farmers adopt this measure. However, some farmers can potentially increase their own yield by avoiding MSD under high rice prices, which would be maintained through other farmers’ participation. A strong motivation exists for some farmers to gain a “free ride,” and an environmental subsidy with a carbon tax can help motivate farmers to adopt MSD. Therefore, the policy mix of prolonging MSD and environmental subsidies can increase all farmers’ incomes by preventing “free rides” and decrease greenhouse gas emissions with a slight decrease in Japan’s GDP.