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1.
Agricultural soils in China have been estimated to have a large potential for carbon sequestration, and modelling and literature survey studies have yielded contrasting results of soil organic carbon (SOC) stock change, ranging from ?2.0 to +0.6% yr?1. To assess the validity of earlier estimates, we collected 1394 cropland soil profiles from all over the country and measured SOC contents in 2007–2008, and compared them with those of a previous national soil survey conducted in 1979–1982. The results showed that average SOC content in the 0–20 cm soil increased from 11.95 g kg?1 in 1979–1982 to 12.67 g kg?1 in 2007–2008, averaging 0.22% yr?1. The standard deviation of SOC contents decreased. Four major soil types had statistically significant changes in their mean SOC contents for 0–20 cm. These were: +7.5% for Anthrosols (paddy soils), +18.3% for Eutric Cambisols, +30.5% for Fluvisols, and ?22.3% for Chernozems. The change of SOC contents showed a negative relationship with the average SOC contents of the two sampling campaigns only when soils in the region south of Yangtse River were excluded. SOC contents of the two major soil types in the region south of Yangtse River, i.e., Haplic Alisols/Haplic Acrisols and Anthrosols (paddy soils), changed little or significantly increased, though with a high SOC content. We suggest that the increase of SOC content is mainly attributed to the large increase in crop yields since the 1980s, and the short history as cropland establishment is mainly responsible for the decrease in SOC content for some soil types and regions showing a SOC decline. 相似文献
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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
3.
农田生态系统土壤有机碳库及其影响因子 总被引：35，自引：2，他引：35
土壤有机碳(SOC)的数量和质量在很大程度上与维持和提高土壤肥力密切相关。农田生态系统土壤碳库研究一直是农业、生态和环境领域的一个主要方向。土地利用、耕作、作物类型、种植密度、灌溉、施肥以及其他人为活动等,对农田生态系统土壤有机碳库的变化均能产生影响。本文综合评述了农田生态系统土壤有机碳库及其影响因子,土壤碳截获潜力,维持和提高土壤有机碳库的措施,以及农田土壤碳截获在温室气体减排及气候变化中的潜在作用等,最后提出了农田生态系统土壤有机碳库研究的主要方向。 相似文献
4.
This study aimed to investigate the impact of long-term grassland management on the temporal dynamic of SOC density in two temperate grasslands. The top soil SOC density, soil total nitrogen density and soil bulk density (0–20 cm) under long-term fencing and grazing treatments, the aboveground net primary productivity of fenced plots and the associated climatic factors of Leymus chinensis and Stipa grandis grasslands in Inner Mongolia were collected from literatures and analyzed. The results showed that the SOC density increased linearly with fenced duration but was insensitive to grazed duration in both grasslands. Compared with long-term grazing, fenced plots had larger potential for carbon sequestration, and the accumulation rate of SOC density was 29 and 35 g Cm–2y–1 for L. chinensis and S. grandis grasslands. Fenced duration and mean annual temperature jointly contributed large effect on temporal pattern of SOC density. Climate change and grazed duration had little influence on the inter-annual variance of SOC density in grazed plots. Our results confirmed the enhancement effect of long-term fencing on soil carbon sequestration in degraded temperate grassland, and long-term permanent plot observation is essential and effective for accurately and comprehensively understanding the temporal dynamic of SOC storage. 相似文献
5.
生物炭对土壤有机碳矿化的激发效应及其机理研究进展 总被引：11，自引：0，他引：11
近年来由于生物炭具有碳素稳定性强和孔隙结构发达等特性,其在土壤固碳减排方面的作用研究受到广泛关注.然而当生物炭进入土壤环境后最终是增加土壤碳的储存还是促进土壤碳的排放?目前学术界对该问题仍存在争议.生物炭对土壤有机碳的激发效应及其机理研究有待进一步深入开展.本文在分析生物炭自身碳素组分和稳定性、孔隙结构及表面形态特征的基础上,综述了添加生物炭对土壤本底有机碳矿化产生激发效应的研究进展,分别阐述了产生正激发和负激发效应(即促进和抑制矿化)的机制机理,认为正激发效应主要是基于生物炭促进土壤微生物活性增强、生物炭中易分解组分的优先矿化以及由此引发的土壤微生物的共代谢作用,而负激发效应主要是基于生物炭内部孔隙结构和外表面对土壤有机质的包封作用和吸附保护作用、生物炭促进土壤有机-无机复合体形成的稳定化作用、生物炭对土壤微生物及其酶活性的抑制作用.最后对今后相关研究方向进行了展望,以期为生物炭在土壤固碳减排方面的应用提供理论依据. 相似文献
6.
Soussana JF Tallec T Blanfort V 《Animal : an international journal of animal bioscience》2010,4(3):334-350
Soil carbon sequestration (enhanced sinks) is the mechanism responsible for most of the greenhouse gas (GHG) mitigation potential in the agriculture sector. Carbon sequestration in grasslands can be determined directly by measuring changes in soil organic carbon (SOC) stocks and indirectly by measuring the net balance of C fluxes. A literature search shows that grassland C sequestration reaches on average 5 ± 30 g C/m2 per year according to inventories of SOC stocks and -231 and 77 g C/m2 per year for drained organic and mineral soils, respectively, according to C flux balance. Off-site C sequestration occurs whenever more manure C is produced by than returned to a grassland plot. The sum of on- and off-site C sequestration reaches 129, 98 and 71 g C/m2 per year for grazed, cut and mixed European grasslands on mineral soils, respectively, however with high uncertainty. A range of management practices reduce C losses and increase C sequestration: (i) avoiding soil tillage and the conversion of grasslands to arable use, (ii) moderately intensifying nutrient-poor permanent grasslands, (iii) using light grazing instead of heavy grazing, (iv) increasing the duration of grass leys; (v) converting grass leys to grass-legume mixtures or to permanent grasslands. With nine European sites, direct emissions of N2O from soil and of CH4 from enteric fermentation at grazing, expressed in CO2 equivalents, compensated 10% and 34% of the on-site grassland C sequestration, respectively. Digestion inside the barn of the harvested herbage leads to further emissions of CH4 and N2O by the production systems, which were estimated at 130 g CO2 equivalents/m2 per year. The net balance of on- and off-site C sequestration, CH4 and N2O emissions reached 38 g CO2 equivalents/m2 per year, indicating a non-significant net sink activity. This net balance was, however, negative for intensively managed cut sites indicating a source to the atmosphere. In conclusion, this review confirms that grassland C sequestration has a strong potential to partly mitigate the GHG balance of ruminant production systems. However, as soil C sequestration is both reversible and vulnerable to disturbance, biodiversity loss and climate change, CH4 and N2O emissions from the livestock sector need to be reduced and current SOC stocks preserved. 相似文献
7.
Xiangrui Xu Kun Cheng Hua Wu Jianfei Sun Qian Yue Genxing Pan 《Global Change Biology Bioenergy》2019,11(4):592-605
Biochar soil amendment (BSA) had been advocated as a promising approach to mitigate greenhouse gas (GHG) emissions in agriculture. However, the net GHG mitigation potential of BSA remained unquantified with regard to the manufacturing process and field application. Carbon footprint (CF) was employed to assess the mitigating potential of BSA by estimating all the direct and indirect GHG emissions in the full life cycles of crop production including production and field application of biochar. Data were obtained from 7 sites (4 sites for paddy rice production and 3 sites for maize production) under a single BSA at 20 t/ha?1 across mainland China. Considering soil organic carbon (SOC) sequestration and GHG emission reduction from syngas recycling, BSA reduced the CFs by 20.37–41.29 t carbon dioxide equivalent ha?1 (CO2‐eq ha?1) and 28.58–39.49 t CO2‐eq ha?1 for paddy rice and maize production, respectively, compared to no biochar application. Without considering SOC sequestration and syngas recycling, the net CF change by BSA was in a range of ?25.06 to 9.82 t CO2‐eq ha?1 and ?20.07 to 5.95 t CO2‐eq ha?1 for paddy rice and maize production, respectively, over no biochar application. As the largest contributors among the others, syngas recycling in the process of biochar manufacture contributed by 47% to total CF reductions under BSA for rice cultivation while SOC sequestration contributed by 57% for maize cultivation. There was a large variability of the CF reductions across the studied sites whether in paddy rice or maize production, due likely to the difference in GHG emission reductions and SOC increments under BSA across the sites. This study emphasized that SOC sequestration should be taken into account the CF calculation of BSA. Improved biochar manufacturing technique could achieve a remarkable carbon sink by recycling the biogas for traditional fossil‐fuel replacement. 相似文献
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9.
WEI Ning SHE Qian-nan PENG Xia ZHU Xi-yang PAN Chen XU Qian LIU Min XIANG Wei-ning 《生态学杂志》2016,35(9):2471
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11.
Chuancheng Fu Yuan Li Lin Zeng Haibo Zhang Chen Tu Qian Zhou Kuanxu Xiong Jiaping Wu Carlos M. Duarte Peter Christie Yongming Luo 《Global Change Biology》2021,27(1):202-214
Global vegetated coastal habitats (VCHs) represent a large sink for organic carbon (OC) stored within their soils. The regional patterns and causes of spatial variation, however, remain uncertain. The sparsity and regional bias of studies on soil OC stocks from Chinese VCHs have limited the reliable estimation of their capacity as regional and global OC sinks. Here, we use field and published data from 262 sampled soil cores and 181 surface soils to report estimates of soil OC stocks, burial rates and losses of VCHs in China. We find that Chinese mangrove, salt marsh and seagrass habitats have relatively low OC stocks, storing 6.3 ± 0.6, 7.5 ± 0.6, and 1.6 ± 0.6 Tg C (±95% confidence interval) in the top meter of the soil profile with burial rates of 44 ± 17, 159 ± 57, and 6 ± 45 Gg C/year, respectively. The variability in the soil OC stocks is linked to biogeographic factors but is mostly impacted by sedimentary processes and anthropic activities. All habitats have experienced significant losses, resulting in estimated emissions of 94.2–395.4 Tg CO2e (carbon dioxide equivalent) over the past 70 years. Reversing this trend through conservation and restoration measures has, therefore, great potential in contributing to the mitigation of climate change while providing additional benefits. This assessment, on a national scale from highly sedimentary environments under intensive anthropogenic pressures, provides important insights into blue carbon sink mechanism and sequestration capacities, thus contributing to the synchronous progression of global blue carbon management. 相似文献
12.
为了考查繁殖期不同性别鲫鱼(Carassius auratus)的运动能力及生理代谢特征,在20±1℃条件下,分别依次测定1龄且处于繁殖第Ⅲ期不同性别实验鱼的快速启动、临界游泳速度(Ucrit)、静止代谢率(MO2rest)、最大运动代谢率(MO2active)及运动过程中的代谢率(MO2)。结果表明:鲫鱼雌鱼与雄鱼的临界游泳速度(Ucrit)分别为6.97±0.22、7.29±0.31BL.s-1,差异不显著;雌、雄鱼快速启动中的最大运动速度(Vmax)分别为20.48±0.69、20.40±1.09BL.s-1,无显著差异,同时它们的最大加速度(amax)、反应时间、120ms内移动距离同样均无显著差异;雌鱼与雄鱼的MO2rest差异不显著;MO2active与代谢空间(△MO2)分别为341.92±22.59、307.50±22.66mgO2.kg-1.h-1和257.18±18.51、220.20±18.95mgO2.kg-1.h-1,前者均显著高于后者(P<0.01)。可见,处于繁殖Ⅲ期的鲫鱼雌鱼与雄鱼的Ucrit及快速启动均无显著差异;并且雌鱼有氧运动能力的维持存在功率补偿。 相似文献
13.
基于华北地区3个长期定位试验站点（河南郑州、山东禹城和河北曲周）的试验数据,用站点实测作物产量和土壤有机碳（SOC）双标准对Daycent模型进行校验和验证.结果表明： 模型参数组合对作物产量和SOC的长期变化动态拟合效果良好,表明Daycent模型可较好地模拟作物产量和SOC的动态变化.用校验和验证了的模型对3个站点在气候情景RCP 4.5下4种不同管理措施（单施化肥NPK、化肥+有机肥MNPK、秸秆还田SNPK、免耕+秸秆NT）下SOC的变化动态进行模拟.结果表明： 郑州站点NPK、MNPK、SNPK处理中,MNPK处理的SOC相对年平均增幅最高,2001—2050年间的SOC年增幅达1.7%,其次为SNPK处理（年均增幅为1.3%）和NPK处理（年均增幅为0.8%）,从长远角度看,增施有机肥对灌溉轻壤土有机碳的增加有明显效果.在禹城站点,研究期间,MNPK处理的SOC年均增幅（0.4%）高于NPK处理（0.3%）,由于该站点土壤有轻度盐化特征,因此各措施下SOC的增幅较低.在曲周站点,NT处理更有利于SOC的增加,研究期间的SOC年均增幅达1.3%,远高于SNPK处理（0.7%）和NPK处理（0.4%）.华北地区气温适宜、灌溉条件好、具备秸秆还田及免耕机械条件,免耕+秸秆还田是该地区增加SOC的较好农作管理措施. 相似文献
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Tim‐Martin Wertebach Norbert Hölzel Immo Kämpf Andrey Yurtaev Sergey Tupitsin Kathrin Kiehl Johannes Kamp Till Kleinebecker 《Global Change Biology》2017,23(9):3729-3741
The break‐up of the Soviet Union in 1991 triggered cropland abandonment on a continental scale, which in turn led to carbon accumulation on abandoned land across Eurasia. Previous studies have estimated carbon accumulation rates across Russia based on large‐scale modelling. Studies that assess carbon sequestration on abandoned land based on robust field sampling are rare. We investigated soil organic carbon (SOC) stocks using a randomized sampling design along a climatic gradient from forest steppe to Sub‐Taiga in Western Siberia (Tyumen Province). In total, SOC contents were sampled on 470 plots across different soil and land‐use types. The effect of land use on changes in SOC stock was evaluated, and carbon sequestration rates were calculated for different age stages of abandoned cropland. While land‐use type had an effect on carbon accumulation in the topsoil (0–5 cm), no independent land‐use effects were found for deeper SOC stocks. Topsoil carbon stocks of grasslands and forests were significantly higher than those of soils managed for crops and under abandoned cropland. SOC increased significantly with time since abandonment. The average carbon sequestration rate for soils of abandoned cropland was 0.66 Mg C ha?1 yr?1 (1–20 years old, 0–5 cm soil depth), which is at the lower end of published estimates for Russia and Siberia. There was a tendency towards SOC saturation on abandoned land as sequestration rates were much higher for recently abandoned (1–10 years old, 1.04 Mg C ha?1 yr?1) compared to earlier abandoned crop fields (11–20 years old, 0.26 Mg C ha?1 yr?1). Our study confirms the global significance of abandoned cropland in Russia for carbon sequestration. Our findings also suggest that robust regional surveys based on a large number of samples advance model‐based continent‐wide SOC prediction. 相似文献
15.
Soil application of Ca- and Mg-rich silicates can capture and store atmospheric carbon dioxide as inorganic carbon but could also have the potential to stabilise soil organic matter (SOM). Synergies between these two processes have not been investigated. Here, we apply finely ground silicate rock mining residues (basalt and granite blend) to a loamy sand in a pot trial at a rate of 4% (equivalent to 50 t ha−1) and investigate the effects of a wheat plant and two watering regimes on soil carbon sequestration over the course of 6 months. Rock dust addition increased soil pH, electric conductivity, inorganic carbon content and soil-exchangeable Ca and Mg contents, as expected for weathering. However, it decreased exchangeable levels of micronutrients Mn and Zn, likely related to the elevated soil pH. Importantly, it increased mineral-associated organic matter by 22% due to the supply of secondary minerals and associated sites for SOM sorption. Additionally, in the nonplanted treatments, rock supply of Ca and Mg increased soil microaggregation that subsequently stabilised labile particulate organic matter as organic matter occluded in aggregates by 46%. Plants, however, reduced soil-exchangeable Mg and Ca contents and hence counteracted the silicate rock effect on microaggregates and carbon within. We suggest this cation loss might be attributed to plant exudates released to solubilise micronutrients and hence neutralise plant deficiencies. The effect of enhanced silicate rock weathering on SOM stabilisation could substantially boost its carbon sequestration potential. 相似文献
16.
Research in the soil of the tropics mostly has demonstrated the decline of soil organic carbon (SOC) after conversion of primary forest to plantation and cultivated lands. This paper illustrates the dynamics of SOC on the island of Java, Indonesia, from 1930 to 2010. We used 2002 soil profile observations containing organic carbon (C) analysis in the topsoil, which were collected by the Indonesian Center for Agricultural Land Resources Research & Development from 1923 to 2007. Results show the obvious decline of SOC values from around 2% in 1930–1940 to 0.8% in 1960–1970. However, there has been an increase of SOC content since 1970, with a median level of 1.1% in the year 2000. Our analysis suggests that the human influence and agricultural practices on SOC in Java have been a stronger influence than the environmental factors. SOC for the top 10 cm has shown a net accumulation rate of 0.2–0.3 Mg C ha?1 yr?1 during the period 1990–2000. These findings give rise to optimism for increased soil C sequestration in the tropics. 相似文献
17.
JULIE MAJOR JOHANNES LEHMANN MARCO RONDON CHRISTINE GOODALE 《Global Change Biology》2010,16(4):1366-1379
Black carbon (BC) is an important pool of the global C cycle, because it cycles much more slowly than others and may even be managed for C sequestration. Using stable isotope techniques, we investigated the fate of BC applied to a savanna Oxisol in Colombia at rates of 0, 11.6, 23.2 and 116.1 t BC ha?1, as well as its effect on non‐BC soil organic C. During the rainy seasons of 2005 and 2006, soil respiration was measured using soda lime traps, particulate and dissolved organic C (POC and DOC) moving by saturated flow was sampled continuously at 0.15 and 0.3 m, and soil was sampled to 2.0 m. Black C was found below the application depth of 0–0.1 m in the 0.15–0.3 m depth interval, with migration rates of 52.4±14.5, 51.8±18.5 and 378.7±196.9 kg C ha?1 yr?1 (±SE) where 11.6, 23.2 and 116.1 t BC ha?1, respectively, had been applied. Over 2 years after application, 2.2% of BC applied at 23.2 t BC ha?1 was lost by respiration, and an even smaller fraction of 1% was mobilized by percolating water. Carbon from BC moved to a greater extent as DOC than POC. The largest flux of BC from the field (20–53% of applied BC) was not accounted for by our measurements and is assumed to have occurred by surface runoff during intense rain events. Black C caused a 189% increase in aboveground biomass production measured 5 months after application (2.4–4.5 t additional dry biomass ha?1 where BC was applied), and this resulted in greater amounts of non‐BC being respired, leached and found in soil for the duration of the experiment. These increases can be quantitatively explained by estimates of greater belowground net primary productivity with BC addition. 相似文献
18.
The stability and decomposition of biochar are fundamental to understand its persistence in soil, its contribution to carbon (C) sequestration, and thus its role in the global C cycle. Our current knowledge about the degradability of biochar, however, is limited. Using 128 observations of biochar‐derived CO2 from 24 studies with stable (13C) and radioactive (14C) carbon isotopes, we meta‐analyzed the biochar decomposition in soil and estimated its mean residence time (MRT). The decomposed amount of biochar increased logarithmically with experimental duration, and the decomposition rate decreased with time. The biochar decomposition rate varied significantly with experimental duration, feedstock, pyrolysis temperature, and soil clay content. The MRTs of labile and recalcitrant biochar C pools were estimated to be about 108 days and 556 years with pool sizes of 3% and 97%, respectively. These results show that only a small part of biochar is bioavailable and that the remaining 97% contribute directly to long‐term C sequestration in soil. The second database (116 observations from 21 studies) was used to evaluate the priming effects after biochar addition. Biochar slightly retarded the mineralization of soil organic matter (SOM; overall mean: ?3.8%, 95% CI = ?8.1–0.8%) compared to the soil without biochar addition. Significant negative priming was common for studies with a duration shorter than half a year (?8.6%), crop‐derived biochar (?20.3%), fast pyrolysis (?18.9%), the lowest pyrolysis temperature (?18.5%), and small application amounts (?11.9%). In contrast, biochar addition to sandy soils strongly stimulated SOM mineralization by 20.8%. This indicates that biochar stimulates microbial activities especially in soils with low fertility. Furthermore, abiotic and biotic processes, as well as the characteristics of biochar and soils, affecting biochar decomposition are discussed. We conclude that biochar can persist in soils on a centennial scale and that it has a positive effect on SOM dynamics and thus on C sequestration. 相似文献
19.
Fan He Wei Hu Fei He Pengze Wang Benyang Pi Mingqin Zhao 《Global Change Biology Bioenergy》2023,15(8):979-993
The employment of biochar in crop production can not only improve soil quality, but also helps the field ecosystem to fix carbon and reduce emissions. Although the benefits of their application in crop production have been more and more confirmed, it is not clear when it comes to the acidic soil of tobacco and rice rotation. A tobacco–rice rotation experiment was conducted in southern China to probe the application value of biochar under these conditions. Three biochar application rates were employed in this experiment. BC0 (without biochar), BC25 (25 t ha−1), and BC50 (50 t ha−1). The findings show that biochar significantly boosted soil fertility and crop yields. Meanwhile, the soil organic carbon of tobacco rice rotation field with biochar increased by 31.76%. After a whole growth period of tobacco and rice, the cumulative emission reduction of CO2 and N2O from the soil by biochar were 15,944 kg ha−1 and 1810 g ha−1, respectively. The use of biochar not only significantly improved the bacterial diversity of tobacco and rice rotation soil, but also altered the original microbial community structure. The profusion of Proteobacteria and Acidobacteria was reduced and the abundance of Actinobacteria and Bacteroidetes was enhanced in the treatments with biochar. Among them, Sphingomonadales, Planctomycotes, and Ktedonobacteria, which are beneficial to plant growth and soil health, have become key phylotypes. The carbon balance analysis data show that the net carbon sequestration of the two treatments with biochar is positive, while that of the treatment without biochar is negative. In terms of economic benefit, the application of biochar increased the average of 2.055 CNY kg−1 consumed energy (CE) in the whole tobacco–rice rotation system. The ecological benefit was 0.51 kg C kg−1 CE. In conclusion, biochar can be effectively used in the practice of tobacco–rice rotation and acidic soil improvement in southern China. 相似文献