施用生物炭提高酸性红壤茶园土壤的微生物特征及酶活性

通过福建安溪茶园的田间试验定位研究不同小麦秸秆生物炭施入量(0、10、20、40 t/hm~2)对红壤茶园土壤性质、土壤微生物和酶活性的影响,阐明生物炭对酸性茶园土壤的改良效应。结果表明,与不施用生物炭相比,40 t/hm~2生物炭施用量处理显著降低茶园土壤容重达0.23 g/cm~3,土壤碱解氮含量下降29.2%,但土壤有机质、有效磷和速效钾分别增加了62.1%、153.9%和173.6%,同时提高土壤p H值0.88个单位。随着生物炭施用量的增加,茶园土壤中细菌、放线菌、真菌、解钾细菌以及解无机磷细菌的数量分别提高了28.5%～104.4%、27.2%～123.4%、17.0%～35.9%、109.2%～208.2%和150.0%～337.3%,β-葡萄糖苷酶、脲酶和碱性磷酸酶活性也显著增加了45.5%～114.7%、8.6%～21.5%和26.7%～186.6%,而土壤酸性磷酸活性却降低了4.0%～15.6%。相关分析表明土壤有效磷含量与解无机磷细菌、碱性磷酸酶活性存在显著正相关关系,速效钾含量与解钾细菌亦存在显著正相关关系,施用生物炭改善酸性红壤茶园土壤的酸碱环境和微生物活性,有利于促进土壤养分转化。     

Effects of biochar application in forest ecosystems on soil properties and greenhouse gas emissions: a review

Purpose

Forests play a critical role in terrestrial ecosystem carbon cycling and the mitigation of global climate change. Intensive forest management and global climate change have had negative impacts on the quality of forest soils via soil acidification, reduction of soil organic carbon content, deterioration of soil biological properties, and reduction of soil biodiversity. The role of biochar in improving soil properties and the mitigation of greenhouse gas (GHG) emissions has been extensively documented in agricultural soils, while the effect of biochar application on forest soils remains poorly understood. Here, we review and summarize the available literature on the effects of biochar on soil properties and GHG emissions in forest soils.

Materials and methods

This review focuses on (1) the effect of biochar application on soil physical, chemical, and microbial properties in forest ecosystems; (2) the effect of biochar application on soil GHG emissions in forest ecosystems; and (3) knowledge gaps concerning the effect of biochar application on biogeochemical and ecological processes in forest soils.

Results and discussion

Biochar application to forests generally increases soil porosity, soil moisture retention, and aggregate stability while reducing soil bulk density. In addition, it typically enhances soil chemical properties including pH, organic carbon stock, cation exchange capacity, and the concentration of available phosphorous and potassium. Further, biochar application alters microbial community structure in forest soils, while the increase of soil microbial biomass is only a short-term effect of biochar application. Biochar effects on GHG emissions have been shown to be variable as reflected in significantly decreasing soil N₂O emissions, increasing soil CH₄ uptake, and complex (negative, positive, or negligible) changes of soil CO₂ emissions. Moreover, all of the aforementioned effects are biochar-, soil-, and plant-specific.

Conclusions

The application of biochars to forest soils generally results in the improvement of soil physical, chemical, and microbial properties while also mitigating soil GHG emissions. Therefore, we propose that the application of biochar in forest soils has considerable advantages, and this is especially true for plantation soils with low fertility.

     

生物炭及生物硝化抑制剂添加对黄土区设施菜地土壤温室气体排放的影响

通过室内培养试验研究生物炭及生物硝化抑制剂添加对黄土区设施菜地土壤N2O和CO₂排放的影响,并与化学合成硝化抑制剂作对比。试验设置6个处理:不施肥(CK)、施氮(N)、施氮+生物炭(N+BC)、施     

Wheat straw and its biochar had contrasting effects on soil C and N cycling two growing seasons after addition to a Black Chernozemic soil planted to barley

Application of crop residues and its biochar produced through slow pyrolysis can potentially increase carbon (C) sequestration in agricultural production systems. The impact of crop residue and its biochar addition on greenhouse gas emission rates and the associated changes of soil gross N transformation rates in agricultural soils are poorly understood. We evaluated the effect of wheat straw and its biochar applied to a Black Chernozemic soil planted to barley, two growing seasons or 15 months (at the full-bloom stage of barley in the second growing season) after their field application, on CO₂ and N₂O emission rates, soil inorganic N and soil gross N transformation rates in a laboratory incubation experiment. Gross N transformation rates were studied using the ¹⁵N isotope pool dilution method. The field experiment included four treatments: control, addition of wheat straw (30 t ha^?1), addition of biochar pyrolyzed from wheat straw (20 t ha^?1), and addition of wheat straw plus its biochar (30 t ha^?1 wheat straw + 20 t ha^?1 biochar). Fifteen months after their application, wheat straw and its biochar addition increased soil total organic C concentrations (p?=?0.039 and <0.001, respectively) but did not affect soil dissolved organic C, total N and NH₄ ⁺-N concentrations, and soil pH. Biochar addition increased soil NO₃ ^?-N concentrations (p?=?0.004). Soil CO₂ and N₂O emission rates were increased by 40 (p?p?=?0.03), respectively, after wheat straw addition, but were not affected by biochar application. Straw and its biochar addition did not affect gross and net N mineralization rates or net nitrification rates. However, biochar addition doubled gross nitrification rates relative to the control (p?2 and N₂O emissions and enhance soil C sequestration. However, the implications of the increased soil gross nitrification rate and NO₃ ^?-N in the biochar addition treatment for long-term NO₃ ^?-N dynamics and N₂O emissions need to be further studied.     

Impact of biochar addition to soil on greenhouse gas emissions following pig manure application

The application of biochar produced from wood and crop residues, such as sawdust, straw, sugar bagasse and rice hulls, to highly weathered soils under tropical conditions has been shown to influence soil greenhouse gas (GHG) emissions. However, there is a lack of data concerning GHG emissions from soils amended with biochar derived from manure, and from soils outside tropical and subtropical regions. The objective of this study was to quantify the effect on emissions of carbon dioxide (CO₂), nitrous oxide (N₂O) and methane (CH₄) following the addition, at a rate of 18 t ha⁻¹, of two different types of biochar to an Irish tillage soil. A soil column experiment was designed to compare three treatments (n = 8): (1) non-amended soil (2) soil mixed with biochar derived from the separated solid fraction of anaerobically digested pig manure and (3) soil mixed with biochar derived from Sitka Spruce (Picea sitchensis). The soil columns were incubated at 10 °C and 75% relative humidity, and leached with 80 mL distilled water, twice per week. Following 10 weeks of incubation, pig manure, equivalent to 170 kg nitrogen ha⁻¹ and 36 kg phosphorus ha⁻¹, was applied to half of the columns in each treatment (n = 4). Gaseous emissions were analysed for 28 days following manure application. Biochar addition to the soil increased N₂O emissions in the pig manure-amended column, most likely as a result of increased denitrification caused by higher water filled pore space and organic carbon (C) contents. Biochar addition to soil also increased CO₂ emissions. This was caused by increased rates of C mineralisation in these columns, either due to mineralisation of the labile C added with the biochar, or through increased mineralisation of the soil organic matter.     

Effect of straw biochar application on soil carbon,greenhouse gas emissions and nitrogen leaching: A vegetable crop rotation field experiment

Intensive vegetable crop systems are rapidly developing, with consequences for greenhouse gas (GHGs) emissions, nitrogen leaching and soil carbon. We undertook a field trial to explore the effect of biochar application (0, 10, 20 and 40 t ha⁻¹) on these factors in lettuce, water spinach and ice plant rotation. Our results show that the 20 and 40 t ha⁻¹ soil treatments resulted in the SOC content being 26.3% and 29.8% higher than the control (0 t ha⁻¹), respectively, with significant differences among all treatments (p < .05). Biochar application caused N₂O emissions to decrease during the lettuce and water spinach seasons, by 1.5%–33.6% and 12.4%–40.5%, respectively, compared the control, with the 20 t ha⁻¹ application rate resulting in the lowest N₂O emissions. Biochar also decreased the dissolved nitrogen (DN) concentration in leachate by 9.8%–36.2%, following a 7.3%–19.9% reduction in dissolved nitrogen in the soil. Similarly, biochar decreased the nitrate (NO₃⁻) concentrations in leachate by 3.9%–30.2%, following a 3.8%–16.7% reduction in the soil nitrate level. Overall, straw biochar applied at rate of 20 t ha⁻¹ produced the lowest N₂O emissions and N leaching, while, increasing soil carbon.     

有机物料还田对冬小麦农田土壤温室气体排放影响的研究

探讨有机物料还田对冬小麦田温室气体排放特性的影响,对提高经济效应和环境效应有积极意义。本研究应用静态箱-气相色谱法对秸秆还田（J）、秸秆还田+牛粪（JF）和秸秆还田+菌渣（JZ）3种有机物料还田下分别施氮肥243 kg （N）·hm^-2（减氮10%,N1）、216 kg （N）·hm^-2（减氮20%,N2）对冬小麦农田N₂O、CO₂和CH₄的排放通量进行监测,探讨了不同施肥措施对麦田温室气体累积排放量、增温潜势的影响。试验期间同步记录每项农事活动机械燃油量、施肥量和灌溉量,测定产量,地上部生物量,估算农田碳截留。结果表明,冬小麦农田土壤N₂O和CO₂是排放源,是CH₄的吸收汇,氮肥施入、灌溉以及强降水促进了土壤N₂O和CO₂的生成,却弱化了CH₄作为大气吸收汇的特征。牛粪+秸秆（JF）处理N₂O和CO₂排放总量最高,分别为3.5 kg （N₂O-N）·hm^-2和19 689.67 kg （CO₂-C）·hm^-2,但CH₄的吸收值最大,为5.33 kg （CH₄-C）·hm^-2,均显著高于菌渣+秸秆（JZ）和秸秆（J）处理（P<0.05）;各处理N₂O和CO₂的总量随施氮量的增加呈升高趋势,CH₄的总量随施氮量的增加而呈降低趋势。JFN2、JN2和JZN2处理农田综合增温潜势（GWP）均为负值,表明有机物料还田且减氮20%条件下农田生态系统为大气的碳汇,麦季净截留碳1 038~2 024 kg·hm^-2,其他处理GWP值均为正。JZN2处理小麦产量为8 061 kg·hm^-2,显著高于JFN2处理（P<0.05）。综上所述,JZN2处理不仅能够保证小麦产量,且对环境效应最有利,为本区域冬小麦较优的施肥管理模式。     

Relationship between greenhouse gas emissions and changes in soil gas diffusivity in a field experiment with biochar and lime

Reducing greenhouse gas emissions from arable soil while maintaining productivity is a major challenge for agriculture. Biochar is known to reduce N₂O emissions from soil, but the underlying mechanisms are unclear. This study examined the impact of green waste biochar (20 Mg ha^?1) and lime (CaCO₃; 2 Mg ha^?1) application on soil gas transport properties and related changes in these to soil N₂O and CO₂ emissions measured using automated chambers in a field experiment cropped with maize. In situ soil water content monitoring was combined with laboratory measurements of relative soil gas diffusion coefficient (D_p/D₀) at different matric potentials, to determine changes in D_p/D₀ over time. Cumulative N₂O emissions were similar in the control and lime treatment, but much lower in the biochar treatment. Cumulative CO₂ emissions decreased in the order: lime treatment > biochar treatment > control soil. When N₂O emissions were not driven by excess N supply shortly after fertilisation, they were associated with D_p/D₀ changes, whereby decreases in D_p/D₀ corresponded to N₂O emissions peaks. No distinct pattern was observed between CO₂ emissions and D_p/D₀. Cumulative N₂O emissions were positively related to number of days with D_p/D₀ < 0.02, a critical limit for soil aeration. These results indicate that improved soil gas diffusivity, and hence improved soil aeration, may explain the effect of biochar in reducing N₂O emissions. They also suggest that knowledge of D_p/D₀ changes may be key to explaining N₂O emissions.     

Short-term effects of raw rice straw and its derived biochar on greenhouse gas emission in five typical soils in China

Abstract

A short-term study was conducted to investigate the greenhouse gas emissions in five typical soils under two crop residue management practices: raw rice straw (Oryza sativa L., cv) and its derived biochar application. Rice straw and its derived biochar (two biochars, produced at 350 and 500°C and referred to as BC350 and BC500, respectively) were incubated with the soils at a 5% (weight/weight) rate and under 70% water holding capacity for 28 d. Incorporation of BC500 into soils reduced carbon dioxide (CO₂) and nitrous oxide (N₂O) emission in all five soils by 4?40% and 62?98%, respectively, compared to the untreated soils, whereas methane (CH₄) emission was elevated by up to about 2 times. Contrary to the biochars, direct return of the straw to soil reduced CH₄ emission by 22?69%, whereas CO₂ increased by 4 to 34 times. For N₂O emission, return of rice straw to soil reduced it by over 80% in two soils, while it increased by up to 14 times in other three soils. When all three greenhouse gases were normalized on the CO₂ basis, the global warming potential in all treatments followed the order of straw > BC350 > control > BC500 in all five soils. The results indicated that turning rice straw into biochar followed by its incorporation into soil was an effective measure for reducing soil greenhouse gas emission, and the effectiveness increased with increasing biochar production temperature, whereas direct return of straw to soil enhanced soil greenhouse gas emissions.     

中国农业源温室气体排放与减排技术对策

农业是重要的温室气体排放源。该文通过对文献资料和大量研究结果进行分析,得出中国农业活动产生的甲烷和氧化亚氮分别占全国甲烷和氧化亚氮排放量的50.15%和92.47%,农业源占全国温室气体排放总量的17%;通过改善反刍动物营养可降低单个肉牛甲烷排放15%～30%;推广稻田间歇灌溉可减少单位面积稻田甲烷排放30%;一个户用沼气每年最大可减少温室气体2.0～4.1 t二氧化碳当量;推行缓释肥、长效肥料可减少单位面积农田氧化亚氮50%～70%。该文建议尽快开展减排技术示范,对减排技术的适应性和经济性进行评价。     

Effects of biochar application on greenhouse gas emissions,carbon sequestration and crop growth in coastal saline soil

To evaluate the benefits of application of biochar to coastal saline soil for climate change mitigation, the effects on soil organic carbon (SOC), greenhouse gases (GHGs) and crop yields were investigated. Biochar was applied at 16 t ha^?1 to study its effects on crop growth (Experiment I). The effects of biochar (0, 3.2, 16 and 32 t ha^?1) and corn stalk (7.8 t ha^?1) on SOC and GHGs were studied using ¹³C stable isotope technology and a static chamber method, respectively (Experiment II). Biochar increased grain mass per plant of the wheat by 27.7% and increased SOC without influencing non‐biochar SOC. On average, 92.3% of the biochar carbon and 16.8% of corn‐stalk carbon were sequestered into the soil within 1 year. The cumulative emissions of CO₂, CH₄ and N₂O were not affected significantly by biochar but cornstalk application increased N₂O emissions by 17.5%. The global warming mitigation potential of the biochar treatments (?3.84 to ?3.17 t CO₂‐eq. ha^?1 t^?1 C) was greater than that of the corn stalk treatment (?0.11 t CO₂‐eq ha^?1 t^?1 C). These results suggest that biochar application improves saline soil productivity and soil carbon sequestration without increasing GHG emissions.     

Impacts of straw biochar additions on agricultural soil quality and greenhouse gas fluxes in karst area,Southwest China

Understanding and improving environmental quality by reducing soil nutrient leaching losses, sequestering carbon (C), reducing greenhouse gas (GHG) emissions, and enhancing crop productivity in highly weathered or degraded soils have always been the goals of agroecosystem researchers and producers. Biochar production and soil incorporation strategies have been recently proposed to help attain these goals. However, the effect of such approaches on soil GHG fluxes is highly uncertain and needs to be further assessed before biochar can be used on a large scale. In addition, the duration of these GHG reductions is not known and is of pivotal importance for the inclusion of biochar in climate abatement strategies. In a field trial cultivated with Chinese cabbage (Brassica campestris ssp. pekinensis) and radish (Daucus carota L. var. Sativa Hoffm), rapeseed (Brassica campestris L.) and maize (Zea mays L.) straw-derived biochar was added to the soil at rates of 0, 26, 64 and 128 t ha^?1, in the whole growing season (October 2011–March 2012) to monitor the effect of treatments on soil GHG production/consumption and soil quality 16 months after biochar addition. The results showed that biochar amendment increased soil pH, nitrate nitrogen content, available phosphorus content and soil water content, but decreased soil bulk density. In biochar-treated plots, soil carbon dioxide (CO₂) fluxes were from 20.1 to 87.0% higher than in the control. Soil methane (CH₄) uptakes were increased significantly, by 33.2 and 80.1%, between the biochar amendment at the rate of 64 and 128 t ha^?1 and the control. Soil nitrous oxide (N₂O) fluxes showed no significant difference between biochar amendment and the control. Overall only the CH₄ uptake-promoting effect continued into the long term, 16 months after biochar incorporation. This study demonstrates that the beneficial effects of biochar addition might first come through soil quality improvement and carbon sequestration, rather than through effects on the repression of soil C mineralization or the nitrogen cycle.     

麦秸与毛叶苕子共同调控青海高原土壤温室气体排放的作用机制

  【目的】  研究青海高原麦秸和豆科绿肥混合添加下土壤温室气体排放规律及其碳氮转化机制,为该地区农田系统秸秆和绿肥科学利用提供依据。  【方法】  采用室内模拟试验,设无添加对照(CK)、单独添加毛叶苕子(VS)、单独添加麦秸(WS)、麦秸与毛叶苕子混合添加(VWS),共4个处理。测定了温室气体排放速率、土壤活性碳氮组分、土壤酶活性、细菌、古菌、真菌、amoA、nirK和narG基因丰度。  【结果】  VWS处理与VS处理相比,CO₂和N₂O的累积排放量分别减少24.8%和74.6%,CH₄累积吸收量增加9.1%,综合增温潜势(global warming potential, GWP)显著降低76.1% (P<0.05);与WS处理相比,CO₂累积排放量增加33.7%,CH₄累积吸收量与N₂O累积排放量分别降低12.0%和43.1%,GWP降低49.4%。有机物料添加可调节土壤pH,增加土壤碳氮含量。VWS处理的土壤pH显著高于CK和VS处理;土壤水溶性有机碳(DOC)和微生物量碳(SMBC)含量较VS处理分别增加了21.6%和4.9%,无机氮(Nmin)、土壤水溶性有机氮(DON)和微生物量氮(SMBN)含量分别降低了77.3%、59.5%和6.3%;土壤Nmin、DOC、DON、SMBC和SMBN含量较WS处理分别增加64.0%、22.5%、56.5%、23.2%和27.8%。VWS处理较其他处理,α-葡萄糖苷酶(AG)和β-葡萄糖苷酶(BG)活性显著提高,亚硝酸还原酶(NIR)活性显著降低。VWS处理的真菌和古菌群落丰度较WS处理分别提高83.8%和69.8%,较VS处理分别降低62.6%和20.3%;VWS处理细菌群落丰度较VS处理降低33.4%。VWS处理下,AOB amoA、nirK和narG基因丰度较VS处理分别降低56.6%、41.4%和16.3%,较WS处理分别降低30.3%、25.9%和12.0%。相关分析结果表明,CO₂和CH₄排放与土壤有机碳、全氮、DOC、SMBC和SMBN含量,AG、NAG和NR活性,真菌、细菌、nirK和narG基因丰度呈显著正相关;N₂O排放与土壤全氮、DON、SMBC和SMBN含量、真菌、AOB amoA和nirK基因丰度呈显著正相关,与土壤pH和BG活性呈显著负相关。偏最小二乘路径模型分析(PLS-PM)表明,AOB amoA是调控土壤N₂O排放的主要功能菌群。  【结论】  麦秸、毛叶苕子单独添加以及二者混合添加均可促进土壤CO₂排放,减少CH₄吸收。相较于二者单独添加,混合添加可通过降低土壤AOB群落丰度等途径,实现N₂O减排和综合增温潜势下降,可作为青海高原旱地土壤温室气体减排的一项有效措施。     

小麦秸秆生物炭对休耕期黄土农田土壤热性质的影响

为了研究小麦秸秆生物炭输入对休耕期农田土壤热性质的影响,共设置了3个小麦秸秆生物炭施用量水平进行田间小区试验,分别为0 kg·m-2(BC0)、1 kg·m-2(BC1)、4 kg·m-2(BC4),每个处理3个重复.对各小区土壤含水率、热容量、导热率、热扩散率和温度等指标进行了测定.结果表明:生物炭施加能显著降低土壤...     

Effects of biochar addition on greenhouse gas emissions during freeze–thaw cycles in a black soil region,Northeast China

As global warming intensifies, the soil environment in middle to high latitudes will undergo more extensive and frequent freeze–thaw cycles (FTCs), which will significantly affect the carbon and nitrogen cycles of soil ecosystems and aggravate greenhouse gas (GHG) emissions. Biochar can increase soil organic carbon storage and mitigate climate change. To effectively control GHG emissions, soil supplemented with biochar at different application rates (0%, 2%, 4% and 6% [w/w]) under different numbers of FTCs (0, 3, 6, 9, and 12) was selected as the research object. The soil GHG emission characteristics in different experimental treatments and their relationships with soil physical and chemical properties were determined. Our results showed that N₂O and CO₂ emissions were promoted during FTCs, with values of 3.13–50.37 and 16.22–135.50 μg m⁻² h⁻¹, respectively. The order of N₂O and CO₂ emissions with respect to biochar application rate was as follows: 2% > 0% > 4% > 6%. CH₄ emissions were negative during FTCs, varying from −1.62 to −10.59 μg m⁻² h⁻¹, and negative CH₄ emissions were promoted by biochar. Correlation analysis showed that N₂O, CO₂ and CH₄ emissions were significantly correlated with pH, soil moisture and soil organic matter (SOM), total nitrogen (TN) and ${\mathrm{NH}}_4^{+}$–N contents (p < .01). The conceptual path model demonstrated that GHG emissions were significantly influenced by FTCs, moisture, SOM and biochar application rate. Our results indicate that the effects of FTCs on GHG emissions were greater than those of biochar application. Biochar application rates of 4% or 6% should be considered in the future to reduce soil GHG emissions in the black soil region of Northeast China. Our results can help provide a theoretical basis and effective strategy to reduce soil GHG emissions during FTCs in seasonally frozen regions.     

生物炭和秸秆还田对干旱区玉米农田土壤温室气体通量的影响

为了研究生物炭及秸秆还田对干旱区玉米农田温室气体通量的影响,以内蒙古科尔沁地区玉米农田为试验对象,采用静态箱-气相色谱法对分别施入生物炭0 t·hm^-2（CK）、15 t·hm^-2（C15）、30 t·hm^-2（C30）、45 t·hm^-2（C45）及秸秆还田（SNPK）的土壤进行温室气体（CO₂、CH₄和N₂O）通量的原位观测,并估算生长季CH₄和N₂O的综合增温潜势（GWP）与排放强度（GHGI）。结果表明：添加生物炭能够显著减少土壤CO₂和N₂O的排放量,并促进土壤对CH₄的吸收作用。其中处理C15对CO₂的减排效果最好,与对照相比CO₂排放量降低21.16%。随着施入生物炭量的增加,生物炭对N₂O排放的抑制作用不断增强,处理C45对减排效果最好,与对照相比N₂O排放量降低86.25%。处理C15对土壤吸收CH₄的促进效果最好,CH₄吸收量增加56.62%;处理C45对CH₄的排放有促进作用,使生长季土壤吸收CH₄减少81.36%。SNPK对温室气体的减排作用接近处理C15。添加生物炭和秸秆还田对提高玉米产量和降低农田GWP与GHGI均有显著效果,施用生物炭及秸秆还田均有效提高了科尔沁地区的玉米产量,且玉米产量随着施入生物炭含量的增大而提升。从GWP上来看,施用15 t·hm^-2生物炭对温室气体减排的整体效果最好。从GHGI上来看,施用生物炭及秸秆还田均具有一定的经济效益和减排意义,其中施用15 t·hm^-2生物炭的综合效益最高。因此综合经济效益与环境因素,建议科尔沁地区农田在种植玉米时添加15 t·hm^-2生物炭,如不具备购买生物炭条件,可以考虑秸秆还田来实现玉米增产与温室气体减排。     

灌溉方式和秸秆还田对设施番茄田CO2排放的影响

中国北方下沉式设施菜田表层土壤缺失,以及高温高湿的环境条件,导致耕层土壤有机质含量低、矿化快。如何减缓土壤有机质矿化,是该文所关注的焦点问题。该研究采用二因素试验设计,主因素为灌溉方式（传统畦灌施肥、滴灌施肥）,副因素为秸秆（含C量为0、3 500 kg/hm2）。测定了48 h内每3 h的CO2排放通量,以及全生育期CO2日排放通量、土壤温度。结果表明：1）08:00−09:00测定的土壤CO2排放通量与CO2日均排放通量不存在显著差异,二者呈极显著线性正相关关系,其决定系数为0.987;而其他时段测定值与日均值均存在显著差异。2）与传统畦灌相比,无论是否添加秸秆,滴灌处理均显著降低了CO2累积排放量。3）CO2排放高峰出现在定植后8～15 d,随后逐渐降低并趋于平稳;定植后40 d内能检测到处理间CO2日排放通量的差异,此后处理间差异不显著。4）CO2累积排放通量和土壤积温呈显著正相关关系。综上所述,滴灌施肥栽培体系可显著降低土壤CO2排放量,有利于设施菜田土壤有机质的积累。     

Fluctuating water level effects on soil greenhouse gas emissions of returning farmland to wetland

Journal of Soils and Sediments - Future climate change is predicted to have an important impact on regional precipitation patterns. Water level is an important factor influencing soil greenhouse...     

不同秸秆还田年限对稻麦轮作系统温室气体排放的影响

为揭示稻麦轮作系统不同秸秆还田年限下温室气体排放特征及减排调控机制,本研究采用大田小区试验,考察了稻麦轮作不同秸秆还田年限[空白对照(CK)、常规处理秸秆不还田(NT)、1年秸秆还田(SR1)和5年秸秆还田(SR5)]对CH4、CO2和N2O 3种温室气体排放规律的影响,同时测定了土壤固碳量,估算了秸秆焚烧产生的温室气体排放量,综合计算了4种处理对全球变暖的贡献。试验结果表明,SR1和SR5均显著提升CH4和CO2的排放通量,分别高出NT、CK处理73.52%、309.49%和13.29%、13.06%;同时显著降低N2O排放通量,较NT降低29.68%和42.55%;但SR1和SR5之间温室气体排放通量差异不显著;与NT相比,SR1和SR5可以显著提高土壤固碳量517.9%和709.03%,SR5土壤固碳量高出SR1达30.93%;NT秸秆焚烧产生的全球气温变暖贡献为9 698.49 kg(CO2-eqv)·hm?2,比CK高126.98%。综合分析温室气体排放、土壤固碳以及秸秆焚烧3个因素,SR1全球升温贡献最低,显著低于NT 4.72%。短期全量秸秆还田有助于降低总体温室气体排放,长期进行秸秆还田后降低幅度会逐步减小。     

Effects of rice straw incorporation and N fertilizer on ryegrass yield,soil quality,and greenhouse gas emissions from paddy soil

Journal of Soils and Sediments - Ryegrass is usually rotated with rice in southern China. The influences of returning ryegrass residues on rice yield and soil dynamics have been studied...