共查询到20条相似文献，搜索用时 15 毫秒
1.
P. Smith K.W.T. Goulding K.A. Smith D.S. Powlson J.U. Smith P. Falloon K. Coleman 《Soil Use and Management》2000,16(4):251-259
Abstract. A number of changes in agricultural land-management show some potential as carbon mitigation options. However, research has focused on CO2 -carbon mitigation and has largely ignored potential effects of land management change on trace gas fluxes. In this paper, we attempt for the first time, to assess the impact of these changes on fluxes of the important agricultural greenhouse gases, methane and nitrous oxide, in the UK.
The estimates presented here are based on limited evidence and have a great (unquantifiable) uncertainty associated with them, but they show that the relative importance of trace gas fluxes varies enormously among the scenarlos. In some, such as the application of sewage sludge, woodland regeneration and bioenergy production scenarios, the inclusion of estimates for trace gas fluxes makes only a small (<10%) difference to the CO2 -C mitigation potential. In the animal manure and agricultural extensification scenarios, including estimates of trace gas fluxes has a large impact, increasing the CO2 -C mitigation potential by up to 50%. In the no-till scenario, the carbon mitigation potential decreases significantly due to a sharp increase in N2 O emissions under no-till.
When these land-management options are combined for the whole agricultural land area of the UK, including trace gases has an impact on estimated mitigation potentials, and depending upon assumptions for the animal manure scenario, the total mitigation potential either decreases by about 10% or increases by about 30%, potentially shifting the mitigation potential of the scenario closer to the EU's 8% Kyoto target for reduction of CO2 -carbon emissions (12.52 Tg C yr−1 for the UK). 相似文献
The estimates presented here are based on limited evidence and have a great (unquantifiable) uncertainty associated with them, but they show that the relative importance of trace gas fluxes varies enormously among the scenarlos. In some, such as the application of sewage sludge, woodland regeneration and bioenergy production scenarios, the inclusion of estimates for trace gas fluxes makes only a small (<10%) difference to the CO
When these land-management options are combined for the whole agricultural land area of the UK, including trace gases has an impact on estimated mitigation potentials, and depending upon assumptions for the animal manure scenario, the total mitigation potential either decreases by about 10% or increases by about 30%, potentially shifting the mitigation potential of the scenario closer to the EU's 8% Kyoto target for reduction of CO
2.
P. Smith R. Milne D.S. Powlson J.U. Smith P. Falloon K. Coleman 《Soil Use and Management》2000,16(4):293-295
Abstract. The soil sequestration components of recent estimates of the carbon mitigation potential of UK agricultural land were calculated on the basis of a percentage change to the soil carbon stock present in the soil. Recent data suggest that the carbon stock of soil in UK arable land has been overestimated, meaning that potential soil carbon sequestration rates were also overestimated. Here, we present a new estimate of the carbon stock in UK arable land, and present revised estimates for the carbon mitigation potential of UK agricultural land. The stock of soil organic carbon in UK arable land (0–30 cm) is estimated to be 562 Tg, about half of the previous estimate. Consequently, the soil carbon sequestration component of each mitigation option is reduced by about half of previously published values. Since above-ground carbon accumulation and fossil fuel carbon savings remain unchanged by these new soil carbon data, options with a significant non-soil carbon mitigation component are reduced by less than those resulting from soil carbon sequestration alone. The best single mitigation option (bioenergy crop production on surplus arable land) accounts for 3.5 Tg C yr−1 , (2.2% of the UK's 1990 CO2 -carbon emissions), whilst an optimal combined land-use mitigation option accounts for 6.1 Tg C yr−1 (3.9% of the UK's 1990 CO2 -carbon emissions). These revised figures suggest that through manipulation of arable land, the UK could, at best, meet 49% of its contribution to the EU's overall Kyoto CO2 -carbon emission reduction target (8% of 1990 emissions), and 31% of the greater target accepted by the UK (12.5%). Even these reduced estimates show a significant carbon mitigation potential for UK arable land. 相似文献
3.
K.A. Smith 《Soil Use and Management》1999,15(2):71-75
Abstract. Over 170 countries have ratified the UN Framework Convention on Climate Change (UNFCCC) which aims at ‘the stabilisation of greenhouse gases in the atmosphere at a level that will prevent dangerous anthropogenic interference with the climate system’. The Kyoto Protocol, signed in 1997, commits the developed (‘Annex 1′) countries to a reduction in gaseous emissions. The global increase in atmospheric CO2, the main greenhouse gas, comes mainly from fossil fuels (6.5 Gt C yr?1), together with about 1.6 Gt C yr?1 from deforestation. The atmospheric increase is only 3.4 Gt C yr?1, however, due to a net sink in terrestrial ecosystems of about 2 Gt C yr?1, and another in the oceans. Increasing net carbon sequestration by afforestation of previously non-forested land is one way of reducing net national emissions of CO2 that is permitted under the Kyoto Protocol. Future modifications may also allow the inclusion of carbon sequestration brought about by other forestry and agricultural land management practices. However, associated changes in net fluxes of two other greenhouse gases identified in the Protocol — nitrous oxide (N2O) and methane (CH4) — will have to be taken into account. Growth of biomass crops can increase N2O emissions, and drainage of wetlands for forestry or agriculture also increases them, as well as emissions of CO2, while decreasing those of CH4. The problems of how to quantify these soil sources and sinks, to maximize soil C sequestration, and to minimize soil emissions of CH4 and N2O, will present a major scientific challenge over the next few years — one in which the soil science community will have a significant part to play. 相似文献
4.
Vladimir Ćirić Milivoj Belić Ljiljana Nešić Srđan Šeremešić Borivoj Pejić Atila Bezdan 《Archives of Agronomy and Soil Science》2016,62(12):1654-1664
Soil organic carbon (SOC) has a high impact on the sustainability of ecosystems, global environmental processes, soil quality and agriculture. Long-term tillage usually leads to SOC depletion. The purpose of this study was to determine the impact of different land uses on water extractable organic carbon (WEOC) fractions and to evaluate the interaction between the WEOC fractions and other soil properties. Using an extraction procedure at 20°C and 80°C, two fractions were obtained: a cold water extractable organic carbon (CWEOC) and a hot water extractable organic carbon (HWEOC). The results suggest that there is a significant impact from different land uses on WEOC. A lower relative contribution of WEOC in SOC and a lower concentration of labile WEOC fractions are contained in arable soil compared to forestlands. Chernozem soil was characterized by a lower relative contribution of WEOC to the SOC and thus higher SOC stability in contrast to Solonetz and Vertisol soils. Both CWEOC and HWEOC are highly associated with SOC in the silt and clay fraction (<53 µm) and were slightly associated with SOC in the macroaggregate classes. The WEOC fractions were highly and positively correlated with the SOC and mean weight diameter. 相似文献
5.
M. Muoz‐Rojas A. Jordn L. M. Zavala D. De la Rosa S. K. Abd‐Elmabod M. Anaya‐Romero 《Land Degradation u0026amp; Development》2015,26(2):168-179
During the last few decades, land use changes have largely affected the global warming process through emissions of CO2. However, C sequestration in terrestrial ecosystems could contribute to the decrease of atmospheric CO2 rates. Although Mediterranean areas show a high potential for C sequestration, only a few studies have been carried out in these systems. In this study, we propose a methodology to assess the impact of land use and land cover change dynamics on soil organic C stocks at different depths. Soil C sequestration rates are provided for different land cover changes and soil types in Andalusia (southern Spain). Our research is based on the analysis of detailed soil databases containing data from 1357 soil profiles, the Soil Map of Andalusia and the Land Use and Land Cover Map of Andalusia. Land use and land cover changes between 1956 and 2007 implied soil organic C losses in all soil groups, resulting in a total loss of 16·8 Tg (approximately 0·33 Tg y−1). Afforestation increased soil organic C mostly in the topsoil, and forest contributed to sequestration of 8·62 Mg ha−1 of soil organic C (25·4 per cent). Deforestation processes implied important C losses, particularly in Cambisols, Luvisols and Vertisols. The information generated in this study will be a useful basis for designing management strategies for stabilizing the increasing atmospheric CO2 concentrations by preservation of C stocks and C sequestration. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
6.
P. Falloon P. Smith R. I. Bradley R. Milne R. Tomlinson D. Viner M. Livermore & T. Brown 《Soil Use and Management》2006,22(3):274-288
We describe the development and application of an integrated data and modelling system for estimating soil carbon (C) fluxes from mineral soils caused by changes in climate, land use and land management at 1‐km resolution in the UK (RothCUK). The system was developed with the aim of improving methods for United Nations Framework Convention on Climate Change (UNFCCC) and Kyoto Protocol accounting and integrates national scale data sets of soil properties, land use and climate with the Rothamsted carbon model (RothC). A preliminary estimate of soil C fluxes because of land use change (LUC) over the period 1990–2000 is presented as an example application of the system. RothCUK shows LUC to be a net source of CO2 from 1990 to 2000 although the RothC estimate was smaller (6488 kt C) than the estimate from the single exponential model (SEM) method currently used to calculate C fluxes due to LUC for the UK National Greenhouse Gas Inventory (mean: 9412 kt C). Based on previous studies, an uncertainty range in our estimates of ±50–100% seems plausible. In agreement with the SEM, RothCUK suggests that the largest single contributor to soil C fluxes from LUC was conversion of grassland to arable land. Differences between the results may be attributed to differences in the two models and the assumptions and underlying data used in making the calculations. The RothCUK system provides a powerful method for estimating changes in soil C stocks, enabling areas and management systems with particularly large changes in soil C stocks to be located at fine resolution. 相似文献
7.
Youlin Luo Qiquan Li Jie Shen Changquan Wang Bing Li Shu Yuan Bin Zhao Huanxiu Li Junwen Zhao Lingke Guo Shan Li Yuting He 《Land Degradation u0026amp; Development》2019,30(15):1875-1885
The properties of soil organic carbon (SOC) required for carbon sequestration and nutrient availability are contradictory, and the changes in SOC caused by agricultural land use changes remain elusive. Data on the total soil organic carbon (TOC) and labile organic carbon, including easily oxidizable organic carbon (EOC), dissolved organic carbon (DOC), and microbial biomass carbon (MBC), of the soil profile were analysed for four typical agricultural land use scenarios in the Chengdu Plain, China. The impacts of agricultural land use changes on sequestration and nutrient availability of SOC were assessed in this urban agricultural area using the space‐for‐time substitution method. Conversion of land use from a traditional agricultural rotation (rice‐wheat/rapeseed rotation) to afforestation increased the MBC content and decreased the contents of EOC, DOC, and TOC due to the lower input of organic matter, improved aeration of the soil profile, and growth of aboveground biomass. Conversion of a traditional rotation to a rice–garlic rotation resulted in a significant increase in topsoil TOC, slight but insignificant decreases in subsoil TOC, and clear increases in labile organic carbon because of rice planting, rice straw mulch, and reasonable application of chemical fertilizers. In contrast, the conversion of a traditional rotation to a rice–leafy vegetable rotation decreased MBC due to the excessive use of chemical fertilizers that consequently increased EOC, DOC, and TOC. We conclude that afforestation on paddy soil has negative consequences for soil carbon sequestration and a rice–leafy vegetable rotation contributes to carbon sequestration but is detrimental to soil fertility. In addition, the MBC ratio in soil could be the optimal indicator for assessing SOC stability and soil fertility, and more attention should be paid to subsoil carbon changes. 相似文献
8.
青藏高原生态系统土壤有机碳研究进展 总被引：10，自引：3，他引：10
作为\"世界第三极\"的青藏高原,高寒生态系统是青藏高原主要的生态系统之一.它本身是一个复杂而又特殊的系统,因其独特的自然地理环境而形成的高寒土壤更有其独特的性质.本文首先综述了青藏高原高寒生态系统的土壤有机碳储量、估算方法的研究进展及造成估算结果差异的原因,随后对高寒土壤有机碳排放的观测试验进行了综述,探讨了气候变化对高寒生态系统土壤有机碳源汇效应的影响.目前,全球变暖的趋势正在加剧,40 年来,青藏高原气温平均上升了约 0.3 ～ 0.4℃,冻土面积正广泛退缩,这直接导致青藏高原高寒生态系统发生了以植被覆盖度减少、高寒草原草甸面积萎缩等为主要形式的显著退化,植被生产力和土壤有机碳输入量都减少,而温度升高加快了土壤有机碳分解速率,从而影响到高寒生态系统的碳循环和碳储量.青藏高原土壤有机碳的源汇效应问题已成为研究的热点,但是到目前为止,温度升高到底如何影响土壤有机碳的动态变化没有明确的定论,为此,我们必须从长期的观测试验来说明气候变化对土壤碳库的源汇效应. 相似文献
9.
T. Lehtinen N. Schlatter A. Baumgarten L. Bechini J. Krüger C. Grignani L. Zavattaro C. Costamagna H. Spiegel 《Soil Use and Management》2014,30(4):524-538
Soil organic matter (SOM) improves soil physicochemical and biological properties, and the sequestration of carbon in SOM may mitigate climate change. Soil organic carbon (SOC) often decreases in intensive cropping systems. Incorporation of crop residues (CR) may be a sustainable management practice to maintain the SOC levels and to increase soil fertility. This study quantifies the effects of CR incorporation on SOC and greenhouse gas (GHG) emissions (CO2 and N2O) in Europe using data from long‐term experiments. Response ratios (RRs) for SOC and GHG emissions were calculated between CR incorporation and removal. The influence of environmental zones (ENZs), clay content and experiment duration on the RRs was investigated. We also studied how RRs of SOC and crop yields were correlated. A total of 475 RRs were derived from 39 publications. The SOC increased by 7% following CR incorporation. In contrast, in a subsample of cases, CO2 emissions were six times and N2O emissions 12 times higher following CR incorporation. The ENZ had no significant influence on RRs. For SOC concentration, soils with a clay content >35% showed 8% higher RRs compared with soils with clay contents between 18 and 35%. As the experiment progressed, RR for SOC concentration increased. For N2O emissions, RR was significantly greater in experiments with a duration <5 yr compared with 11–20 yr. No significant correlations were found between RR for SOC concentration and yields, but differences between sites and study durations were detected. We suggest that a long duration of crop residue incorporation is a win‐win scenario under a continental climate. We conclude that CR incorporation is important for maintaining SOC, but its influence on GHG emissions should be taken into account as well. 相似文献
10.
Owais Ali WANI Shamal Shasang KUMAR Nazir HUSSAIN Anas Ibni Ali WANI Subhash BABU Parvej ALAM Megna RASHID Simona Mariana POPESCU Sheikh MANSOOR 《土壤圈》2023,33(2):250-267
Carbon(C) is a key constitutive element in living organisms(plants, microbes, animals, and humans). Carbon is also a basic component of agriculture because it plays a dynamic role in crop growth, development, nutrient cycling, soil fertility, and other agricultural features. The presence of C enhances soil physical, chemical, and biological properties. The C cycle supports all life on the Earth by transferring C between living organisms and the environment. The global climate is changing, and th... 相似文献
11.
大量研究证明稻田土壤比旱地土壤更具固碳潜力,但至今对稻田土壤固碳机制的认识尚不甚清楚。本研究于2007年利用两个开垦年代相似,近20多年分别一直种植双季稻和双季玉米的长期定位试验,来比较不同种植模式下土壤有机碳及其组分的差异。结果表明,水田土壤总有机碳和总氮的浓度分别是旱地的2.2倍和2.5倍。与试验前相比,水稻种植显著提高了土壤有机碳的含量,增幅达到30.8%,而旱地的前后差异不显著。在所有团聚体粒径水平上,水田有机碳的浓度均显著高于旱地。其中53～250μm微团聚体相差最大,水田是旱地的近3倍。水田微团聚体保护碳（iPOM_m）在土壤中的浓度是旱地的4.2倍,微团聚体保护碳在总有机碳中的比重也显著高于旱地,达到25.5%,是旱地的2倍。水田和旱地iPOM_m组分碳的差异能够解释其总有机碳差异的42.8%。上述结果可以增强我们对稻田土壤固碳机制的了解,为稻田土壤碳管理提供理论依据。 相似文献
12.
P. K. R. Nair Subhrajit K. Saha Vimala D. Nair Solomon G. Haile 《Land Degradation u0026amp; Development》2011,22(4):395-409
Consequent to the interest in converting degraded lands for cultivation of biofuel crops, concerns have been expressed about greenhouse gas (GHG) emissions resulting from changes in soil‐carbon (C) stock following land conversions. A literature‐based study was undertaken for estimating the magnitude of emission of GHGs, particularly carbon dioxide (CO2), following an assessment of the extent and causes of land degradation and the nature of CO2 emission from soils. The study estimated the potential for CO2 emission resulting from changes in soil‐carbon stock following land conversions, using oil palm (Elaeis guineensis Jacq.) as a case study. The analysis indicated that, overall, the magnitude of CO2 emission resulting from changes in soil C stock per se following opening up of degraded land would be low compared with other potential sources of CO2 emission. However, lack of data on critical aspects such as baseline soil C status was a limitation of the study. Soil respiration is the single best measure of GHG emission from soils. Fixation of C in additional biomass will compensate, over time, for C loss through soil respiration following a change in land use or land management, unless such changes involve conversion of existing large C stocks. Therefore, any net CO2 emission from soils resulting from changes in soil C stock following opening up of degraded land is likely to be a short‐term phenomenon. The estimations used in the study are based on various assumptions, which need to be validated by experimental field data. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
13.
目的土壤有机碳 (SOC) 矿化是陆地生态系统碳循环的重要组成部分,温度变化显著影响SOC 矿化特征。研究长期不同施肥管理下SOC 矿化特征及其对温度模式(恒温vs. 变温)的响应,可为优化农田碳管理,减缓农业生产对气候变化的影响提供理论依据。方法基于贵州省农业科学院内旱作黄壤长期定位试验,在不施肥 (CK) 、单施化肥 (NPK) 、单施有机肥 (M) 和有机无机肥配施 (NPKM) 4个处理小区采集耕层土壤样品用于室内培养实验。恒温处理为保持15℃;变温处理为10℃→15℃→20℃→15℃→10℃,每6 h匀速变化5℃,24 h为一个循环周期,两温度处理积温相同,共培养32天。采用碱液吸收法测定CO2排放通量,并分析土壤物理化学及生物学性质,阐明不同温度模式下SOC 矿化特征及其主要驱动因素。结果恒温培养条件下,CK、NPK、M和NPKM处理SOC累积矿化量分别为201、175、262和228 mg/kg,相对于CK,M 和NPKM处理的SOC累积矿化分别显著增加了30.6%和13.3%,但NPK处理显著降低了12.7%。变温培养条件下,M处理SOC 累积矿化量较CK显著增加了30.0%,NPK和NPKM处理间无显著差异。与恒温培养相比,变温培养下CK和NPK处理SOC 累积矿化量分别增加了16.2%和25.6%,而M和NPKM处理无显著变化。恒温和变温培养条件下,CO2累积排放量与土壤pH、SOC、全氮、微生物生物量碳氮等指标显著正相关;温度模式变化引起的CO2排放强度变化与土壤微生物生物量碳氮、微生物呼吸熵和碳氮磷转化酶活性显著负相关。结论长期施用有机肥通过增加底物有效性、微生物生物量和酶活性显著促进了SOC矿化,通过改变土壤微生物呼吸熵和碳磷转化酶活性缓解了温度周期性变化对SOC矿化的促进作用。 相似文献
14.
Abstract. An estimate of organic carbon stored in French soils to a depth of 30 cm was made using data from geo-referenced databases. We produced statistics on carbon stocks in soils according to land use, different land uses and soil type. Then, using a combination of maps of soil and land use we were able to estimate regional and national carbon stocks. This soil carbon map of France allowed us to identify the main controlling factors of the carbon distribution: land use, soil type in some cases, clay content, and elevation. Carbon stocks in French soils were found to be about 3.1 Pg (1015 g). 相似文献
15.
Abstract. Knowledge of the stocks and the potential range of soil organic carbon (SOC) in various land–soil combinations is an important precursor to policies aimed at linking, for example, management of SOC to greenhouse gas emission controls. To investigate the factors controlling the percentage of SOC (%SOC) of soils in England and Wales, we made a multiple regression analysis of data for the 2448 arable and ley-arable sites in the 1980 England and Wales National Soil Inventory (NSI). Clay content, average annual precipitation and depth of topsoil explained 25.5% of the variation in %SOC, when calcareous and peaty soils and those susceptible to flooding were excluded. Using 'robust' statistics, 'indicative SOC management ranges' were estimated for different physiotopes, that is, landscape units for which the environmental factors governing %SOC are similar, namely soil clay content and precipitation. These ranges describe the expected %SOC range for an arable soil in a given physiotope. They have potential to support approximate targets for the %SOC of arable soils and for estimating upper and lower limits for sequestered soil carbon in arable systems. 相似文献
16.
《Land Degradation u0026amp; Development》2017,28(1):151-165
Afforestation has been proposed as an effective method of carbon (C) sequestration; however, the magnitude and direction of soil C and nitrogen (N) dynamics following afforestation are not well understood. This study was designed to examine soil C and N dynamics following afforestation and to determine how various factors affect soil organic C (SOC) and total N (TN) after land‐use conversions through the compilation and analysis of published data from 61 individual studies (512 observations at 61 sites in China). This analysis showed that for different previous land uses, post‐afforestation SOC, TN, and C/N ratio varied in diverse temporal patterns. The relationship of soil C–N coupling was related to land use prior to afforestation and forest age. At 0–100 cm soil depths, SOC and TN increased at rates about 0·23 and 0·03 g kg−1 y−1, respectively, and the C/N ratio was about 0·19 y−1. SOC and TN were significantly affected by tree species, forest age, and soil depth. SOC, TN, and C/N were negatively correlated with soil bulk density (p < 0·01) and pH (p > 0·05) but positively correlated with soil total phosphorus (p < 0·01), soil moisture (p < 0·01) and soil microbial biomass C (p < 0·01) and N (p < 0·01). Additionally, SOC and TN were higher for the mid‐level humidity index in China and were also determined by precipitation, temperature, and forest age. These results highlight the importance of previous land use, tree species, soil depth, and forest age in determining soil C and N changes in a range of environments and land‐use transitions. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
17.
Imran Ameer Kashif Ali Kubar Qurban Ali Shahmir Ali Tamoor Khan Khurram Shahzad Muhammad Riaz Zia-ul-hassan Shah Inayatullah Rajpar Muneer Ahmed Khalid Hussain Talpur 《Land Degradation u0026amp; Development》2023,34(3):624-636
Dry stable aggregates, soil organic carbon (SOC) stocks, and aggregate-associated carbon are measured as vital factors for preserving soil quality. Different land use systems strongly impacts the services of the ecosystem to influence soil degradation and loss of carbon. Little is known about the dry aggregates stability and SOC stocks in the dry, semiarid region of Balochistan, Pakistan or how these resist land degradation. This study aimed to assess the impact of several land-use systems on SOC stocks, the distribution of soil aggregates, and the carbon management index. The treatments consisted of five land-use systems, namely, grassland, cropland, fallow land, forests, and vegetation, typically prevail in the region. Three layers of soil were used to sample it (0–15, 15–30, and 30–45 cm) and sieved into five aggregate classes (>8, 8–5, 5–2, 2–0.25, and <0.25 mm). The grasslands had significant higher SOC concentrations (12.83 g kg−1), SOC stocks (19.44 mg ha−1), liability index (0.89 g kg−1), nonlabile C (9.56 g kg−1), labile C (0.35 g kg−1), carbon management index (204.6), and easily oxidizable carbon (3.27 g kg−1), when compared with fallow land. Moreover, grassland and forestland soils contained larger macroaggregates (>0.25 mm), although the fallow land-use system had a higher degree of micro aggregates (<0.25 mm). We found strong relationship of soil SOC with SOC concentration of soil aggregates and other labile fractions of carbon. Therefore, grassland and forestland promotes the aggregate-associated SOC and carbon management index by enhancing the soil aggregation and is therefore a possible managing option to develop the SOC sequestration potential of eroded dry soils. 相似文献
18.
探讨长期种植作物对农田土壤有机碳的影响程度,对于早日实现农业“碳中和”与可持续发展具有重要意义。以Meta整合分析法定量分析长期种植作物下中国农田土壤有机碳含量的变化特征,并系统分析各类因素的影响程度。结果表明,中国长期种植作物耕层土壤有机碳含量整体提高了17.85%,但随土层加深有机碳增幅呈降低趋势。当海拔为200～600 m、温度为8～15 ℃和降水为600～1000 mm时土壤有机碳的积累程度最大。除pH和碱解氮外,随着初始土壤养分含量的增加,有机碳增幅呈下降趋势,其中土壤有机碳为0～10 g·kg-1、全氮为0～0.9 g·kg-1、速效磷为0～10 mg·kg-1、速效钾为0～75 mg·kg-1时有机碳增幅最大。中国相对温暖湿润的低海拔暖温带地区更有利于农田土壤有机碳的积累。随土层加深,长期种植作物对土壤有机碳增加的影响逐渐降低。除碱解氮外,初始养分越贫瘠的土壤越有利于有机碳的积累。在各类田间管理措施中,秸秆全量还田对促进土壤有机碳的积累最为有效。 相似文献
19.
黄土丘陵区退耕撂荒对土壤有机碳的积累及其活性的影响 总被引：27，自引：1，他引：27
土壤有机碳是陆地生态系统的重要碳库之一,增加土壤中碳的储量对于减缓全球变暖的趋势具有重要意义。通过野外样品采集及室内分析,比较了退耕1年,3年,5年,7年,10年,15年和25年7个不同年限撂荒地的土壤有机碳及其活性的变化。结果表明:耕地撂荒后,表层土壤有机碳及活性有机碳的含量随着退耕年限的增长呈增加趋势;土壤中的腐殖质以胡敏素为主,占总有机碳含量的70%～80%;深度在40cm以上的表土,腐殖酸总量及各组分含量都随着撂荒年限的增长呈递增趋势。说明耕地撂荒后,土壤中有机碳的含量明显增高,对增加土壤中有机碳的储量具有积极的意义;同时植被恢复后也减少了土壤中有机碳的流失。 相似文献
20.
Abstract. A model of the impact of land management changes upon soil organic carbon (SOC) was constructed, and the total amount of topsoil organic carbon was estimated for the arable area of England from 1940 to 2000. The largest influence on the overall mean SOC in arable topsoils proved to be a decline in the area of both permanent and temporary grassland. SOC declined over a prolonged period (60 years), but has now reached a plateau. Modelling changes in mean values enabled a statistical evaluation to be made between a measured decline in the number of sites with 'high' SOC levels between 1980 and 1995, and the decline predicted by the model. The SOC content of arable soils in England was measured at National Soil Inventory sites twice in recent decades: in 1980 and 1995. The proportion of fine textured soils in the lowest SOC class (<2.3%) rose from just over 40% to about 50% over the same period. There was a significant difference between the observed values of 1995 and those expected from modelling the decline from 1980 values, in the category of 'low SOC' fine textured soils. The variation in the fine textured soils represents a significant and widespread decline in topsoil organic carbon concentrations, which was greater than the underlying long-term trend. 相似文献