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1.
Carbon dynamics in successional and afforested spruce stands in Thuringia and the Alps 总被引：4，自引：0，他引：4
Changes in the carbon stocks of stem biomass, organic layers and the upper 50 cm of the mineral soil during succession and afforestation of spruce (Picea abies) on former grassland were examined along six chronosequences in Thuringia and the Alps. Three chronosequences were established on calcareous and three on acidic bedrocks. Stand elevation and mean annual precipitation of the chronosequences were different. Maximum stand age was 93 years on acid and 112 years on calcareous bedrocks. Stem biomass increased with stand age and reached values of 250–400 t C ha?1 in the oldest successional stands. On acidic bedrocks, the organic layers accumulated linearly during forest succession at a rate of 0.34 t C ha?1 yr?1. On calcareous bedrocks, a maximum carbon stock in the humus layers was reached at an age of 60 years. Total carbon stocks in stem biomass, organic layers and the mineral soil increased during forest development from 75 t C ha?1 in the meadows to 350 t C ha?1 in the oldest successional forest stands (2.75 t C ha?1 yr?1). Carbon sequestration occurred in stem biomass and in the organic layers (0.34 t C ha?1 yr?1on acid bedrock), while mineral soil carbon stocks declined. Mineral soil carbon stocks were larger in areas with higher precipitation. During forest succession, mineral soil carbon stocks of the upper 50 cm decreased until they reached approximately 80% of the meadow level and increased slightly thereafter. Carbon dynamics in soil layers were examined by a process model. Results showed that sustained input of meadow fine roots is the factor, which most likely reduces carbon losses in the upper 10 cm. Carbon losses in 10–20 cm depth were lower on acidic than on calcareous bedrocks. In this depth, continuous dissolved organic carbon inputs and low soil respiration rates could promote carbon sequestration following initial carbon loss. At least 80 years are necessary to regain former stock levels in the mineral soil. Despite the comparatively larger amount of carbon stored in the regrowing vegetation, afforestation projects under the Kyoto protocol should also aim at the preservation or increase of carbon in the mineral soil regarding its greater stability of compared with stocks in biomass and humus layers. If grassland afforestation is planned, suitable management options and a sufficient rotation length should be chosen to achieve these objectives. Maintenance of grass cover reduces the initial loss. 相似文献
2.
土壤固碳功能和固碳潜力已成为全球气候变化和陆地生态系统研究的重点。草地土壤有机碳库,作为陆地土壤有机碳库的重要组成部分,其较小幅度的波动,将会影响整个陆地生态系统碳循环,进而影响全球气候变化。因此,深入研究草地土壤固碳功能和固碳潜力对于适应和减缓气候变化具有重要意义。在土壤固碳潜力相关概念界定基础上,结合《2006年IPCC国家温室气体清单指南》,从样点及区域尺度上综述了目前关于草地土壤固碳潜力的一般估算方法,同时对各类方法的特点及适用性进行了评述,提出了草地生态系统固碳潜力研究概念模型。最后在对草地土壤固碳的影响因素及固碳措施总结的基础上,阐明了草地土壤有机碳固定研究中存在的问题和发展前景。 相似文献
3.
Chronosequences are commonly used to assess soil organic carbon (SOC) sequestration after land‐use change, but SOC dynamics predicted by this space‐for‐time substitution approach have rarely been validated by resampling. We conducted a combined chronosequence/resampling study in a former cropland area (Vestskoven) afforested with oak (Quercus robur) and Norway spruce (Picea abies) over the past 40 years. The aims of this study were (i) to compare present and previous chronosequence trends in forest floor and top mineral soil (0–25 cm) C stocks; (ii) to compare chronosequence estimates with current rates of C stock change based on resampling at the stand level; (iii) to estimate SOC changes in the subsoil (25–50 cm); and (iv) to assess the influence of two tree species on SOC dynamics. The two chronosequence trajectories for forest floor C stocks revealed consistently higher rates of C sequestration in spruce than oak. The chronosequence trajectory was validated by resampling and current rates of forest floor C sequestration decreased with stand age. Chronosequence trends in topsoil SOC in 2011 did not differ significantly from those reported in 1998, however, there was a shift from a negative rate (1998: ?0.3 Mg C ha?1 yr?1) to no change in 2011. In contrast SOC stocks in the subsoil increased with stand age, however, not significantly (P = 0.1), suggesting different C dynamics in and below the former plough layer. Current rates of C change estimated by repeated sampling decreased with stand age in forest floors but increased in the topsoil. The contrasting temporal change in forest floor and mineral soil C sequestration rates indicate a shift in C source‐sink strength after approximately 40 years. We conclude that afforestation of former cropland within the temperate region may induce soil C loss during the first decades followed by a recovery phase of yet unknown duration. 相似文献
4.
桑思月;杨沂杰;赵京东;乌云娜;吕林有;宋彦涛 《生态学杂志》2025,44(3):884-891
以辽西北农牧交错带退化草地为研究对象;研究土壤有机碳含量、储量以及土壤固碳能力随围封年限的变化特征。结果表明: 围封6年后0～20 cm土层土壤有机碳储量增加了18.6%。随围封年限的增加;土壤有机碳含量、储量均呈现下降-上升-下降-上升的“W”型的变化趋势;围封3年、6年时;土壤固碳潜力较高。相关性分析结果表明;0～10 cm土壤有机碳储量与土壤pH呈显著负相关（P<0.05）;与凋落物量、地上生物量呈显著正相关（P<0.05）;10～20 cm土壤有机碳储量与凋落物量呈显著正相关、与植物优势度指数呈显著负相关（P<0.05）。短期围封（6年）通过增加地上生物量促进土壤有机碳的积累;同时通过降低土壤pH减缓有机碳分解;从而增加土壤有机碳含量和固碳潜力。本研究为辽西北退化草地的生态恢复提供了技术支撑。 相似文献
5.
Irina Kurganova Valentin Lopes de Gerenyu Johan Six Yakov Kuzyakov 《Global Change Biology》2014,20(3):938-947
The collapse of collective farming in Russia after 1990 and the subsequent economic crisis led to the abandonment of more than 45 million ha of arable lands (23% of the agricultural area). This was the most widespread and abrupt land use change in the 20th century in the northern hemisphere. The withdrawal of land area from cultivation led to several benefits including carbon (C) sequestration. Here, we provide a geographically complete and spatially detailed analysis of C sequestered in these abandoned lands. The average C accumulation rate in the upper 20 cm of mineral soil was 0.96 ± 0.08 Mg C ha?1 yr?1 for the first 20 years after abandonment and 0.19 ± 0.10 Mg C ha?1 yr?1 during the next 30 years of postagrogenic evolution and natural vegetation establishment. The amount of C sequestered over the period 1990–2009 accounts to 42.6 ± 3.8 Tg C per year. This C sequestration rate is equivalent to ca. 10% of the annual C sink in all Russian forests. Furthermore, it compensates all fire and postfire CO2 emissions in Russia and covers about 4% of the global CO2 release due to deforestation and other land use changes. Our assessment shows a significant mitigation of increasing atmospheric CO2 by prolonged C accumulation in Russian soils caused by collective farming collapse. 相似文献
6.
Iain Goodrick Paul N. Nelson Murom Banabas Christopher M. Wurster Michael I. Bird 《Global Change Biology Bioenergy》2015,7(2):263-272
Oil palm (Elaeis guineensis Jacq.) crops are expanding rapidly in the tropics, with implications for the global carbon cycle. Little is currently known about soil organic carbon (SOC) dynamics following conversion to oil palm and virtually nothing for conversion of grassland. We measured changes in SOC stocks following conversion of tropical grassland to oil palm plantations in Papua New Guinea using a chronosequence of plantations planted over a 25‐year period. We further used carbon isotopes to quantify the loss of grassland‐derived and gain in oil palm‐derived SOC over this period. The grassland and oil palm soils had average SOC stocks of 10.7 and 12.0 kg m?2, respectively, across all the study sites, to a depth of 1.5 m. In the 0–0.05 m depth interval, 0.79 kg m?2 of SOC was gained from oil palm inputs over 25 years and approximately the same amount of the original grass‐derived SOC was lost. For the whole soil profile (0–1.5 m), 3.4 kg m?2 of SOC was gained from oil palm inputs with no significant losses of grass‐derived SOC. The grass‐derived SOC stocks were more resistant to decrease than SOC reported in other studies. Black carbon produced in grassfires could partially but not fully account for the persistence of the original SOC stocks. Oil palm‐derived SOC accumulated more slowly where soil nitrogen contents where high. Forest soils in the same region had smaller carbon stocks than the grasslands. In the majority of cases, conversion of grassland to oil palm plantations in this region resulted in net sequestration of soil organic carbon. 相似文献
7.
Shifts in plant‐community composition following habitat degradation and species invasions can alter ecosystem structure and performance of ecosystem services. In temperate North American woodlands, invasion by aggressive Eurasian shrubs has produced dense thickets with depauperate understory vegetation and increased rates of litter decomposition and nutrient cycling, attributes that could impair storage of carbon as soil organic matter (SOM). It is important to know if such impairment has occurred and, if so, the extent to which restoration can return this service. We used an oak‐woodland restoration chronosequence in northeastern Illinois to contrast structural and functional attributes of unrestored areas dominated by Rhamnus cathartica (common buckthorn) with areas that had undergone buckthorn removal and ongoing, active management for less than 1 to 14 years. With increasing age, restored areas had higher understory plant diversity and cover (p < 0.0001 and 0.005, respectively) and higher litter mass (p = 0.018). These structural differences were associated with some evidence of reduced soil erosion (p = 0.027–0.135) but greater soil CO2 efflux (p = 0.020–0.033). Total particulate organic matter (POM) in the soil increased with restoration age, which was driven by increases in the slow‐turnover, mineral‐associated SOM fraction. However, variance was high and relationships were only weakly significant (p = 0.082 and 0.083 for total POM and mineral‐associated SOM, respectively). Our results suggest that, in addition to better documented biodiversity benefits, beneficial changes to ecosystem properties and processes may also occur with active, long‐term restoration of degraded woodlands. 相似文献
8.
放牧是影响草地土壤碳固存的重要因素。本研究选取黄土高原水蚀风蚀交错区西部、中部、东部地区及水蚀区,以各区20年以上退耕封禁地为对照,分析3个放牧强度下(羊粪球密度分别为0～10、10～20、>20 ind·m-2)退耕草地0～20 cm土层土壤有机碳储量的分布特征,研究放牧及其强度对退耕草地土壤固碳效应的影响。结果表明: 放牧对交错区西部0～20 cm、东部0～10 cm,水蚀区0～5 cm土层土壤有机碳储量有显著影响,对交错区中部各土层均无显著影响;羊粪球密度0～10、＞20 ind·m-2强度的放牧使交错区西部0～20 cm土层土壤有机碳储量显著降低了34.8%～50.9%,而在其他3个区域,放牧对有机碳储量的影响较退耕封禁地差异不显著。在交错区东部,放牧强度是影响退耕草地土壤有机碳储量的主要因素,而其他3个区域有机碳储量主要受土壤理化性质和(或)枯落物生物量的影响。羊粪球密度10～20 ind·m-2强度的放牧对各区域退耕草地0～20 cm土层土壤有机碳储量无显著影响。 相似文献
9.
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
10.
《植物生态学报》2016,40(4):395
Aims
This study was conducted to investigate carbon stocks in forest ecosystems of different stand ages in Anhui Province, and to identify the carbon sequestration potential of climax forests controlled by the natural environment conditions.
Methods
Data were collected based on field investigations and simulations were made with the BIOME4 carbon cycle model.
Important findings
Currently, the total forest carbon stocks in Anhui Province amounts to 714.5 Tg C: 402.1 Tg C in vegetation and 312.4 Tg C in soil. Generally, both the total and vegetation carbon density exhibit an increasing trend with the natural growth of forest stands. Soil carbon density increases from young to near mature forests, and then gradually decreases thereafter. Young and middle-aged forests account for 75% of the total forest area in Anhui Province, with potentially an additional 125.4 Tg C to be gained after the young and middle-aged forests reach near mature stage. Results of BIOME4 simulations show that potentially an additional 245.7 Tg C, including 153.7 Tg C in vegetation and 92 Tg C in soil, could be gained if the current forests are transformed into climax forest ecosystems in Anhui Province. 相似文献
This study was conducted to investigate carbon stocks in forest ecosystems of different stand ages in Anhui Province, and to identify the carbon sequestration potential of climax forests controlled by the natural environment conditions.
Methods
Data were collected based on field investigations and simulations were made with the BIOME4 carbon cycle model.
Important findings
Currently, the total forest carbon stocks in Anhui Province amounts to 714.5 Tg C: 402.1 Tg C in vegetation and 312.4 Tg C in soil. Generally, both the total and vegetation carbon density exhibit an increasing trend with the natural growth of forest stands. Soil carbon density increases from young to near mature forests, and then gradually decreases thereafter. Young and middle-aged forests account for 75% of the total forest area in Anhui Province, with potentially an additional 125.4 Tg C to be gained after the young and middle-aged forests reach near mature stage. Results of BIOME4 simulations show that potentially an additional 245.7 Tg C, including 153.7 Tg C in vegetation and 92 Tg C in soil, could be gained if the current forests are transformed into climax forest ecosystems in Anhui Province. 相似文献
11.
为阐明安徽省不同林龄的森林生态系统的碳储量现状, 以及现有自然环境条件下顶极森林生态系统的固碳潜力, 采用野外样地调查和BIOME4模型方法对此进行研究。安徽省森林生态系统的现状总碳储量为714.5 Tg C, 其中植被碳402.1 Tg C、土壤碳312.4 Tg C。从幼龄林至过熟林的生长过程中, 森林生态系统的总碳密度和植被碳密度都呈现增长趋势。但土壤碳密度从幼龄林至近熟林阶段呈增加趋势, 近熟林以后出现减少趋势。安徽省幼龄林和中龄林占森林总面积的75%, 若幼、中龄林发展到近熟林阶段, 将增加125.4 Tg C。BIOME4模拟显示: 当森林发展到气候顶极森林时, 安徽省森林生态系统将增加245.7 Tg C, 即总固碳潜力包括植被固碳153.7 Tg C, 土壤固碳92.0 Tg C。 相似文献
12.
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
13.
Sebastian Doetterl Johan Six Bas Van Wesemael Kristof Van Oost 《Global Change Biology》2012,18(7):2218-2232
Recent studies have highlighted the tight coupling between geomorphic processes and soil carbon (C) turnover and suggested that eroding landscapes can stabilize more C than their non‐eroding counterparts. However, large uncertainties remain and a mechanistic understanding of geomorphic effects on C storage in soils is still lacking. Here, we quantified the soil organic carbon (SOC) stock and pool distribution along geomorphic gradients and combined data derived from soil organic matter fractionation and incubation experiments. The size and composition of the SOC pools were strongly related to geomorphic position: 1.6 to 6.2 times more C was stabilized in the subsoils (25–100cm) of depositional profiles than in those of eroding profiles. Subsoil C of depositional profiles is predominantly associated with microaggregates and silt‐sized particles which are associated with pools of intermediate stability. We observed a significantly higher mean residence time for the fast and intermediate turnover pools of buried C at depositional positions, relative to non‐eroding and eroding positions, resulting from the physical protection of C associated with microaggregates and silt particles. Conversely, significant amounts of C were replaced at eroding positions but the lower degree of decomposition and the lack of physically protected C, resulted in higher respiration rates. By considering C cycling at non‐eroding, eroding and depositional positions, we found that the eroding landscapes studied store up to 10% more C due to soil redistribution processes than non‐eroding landscapes. This is the result of the stabilization of C in former subsoil at eroding positions and partial preservation of buried C in pools of intermediate turnover at depositional positions. However, the sink strength was limited by significant losses of buried C as only a small fraction of the C was associated with stable pools. 相似文献
14.
Sam R. McNally Mike H. Beare Denis Curtin Esther D. Meenken Francis M. Kelliher Roberto Calvelo Pereira Qinhua Shen Jeff Baldock 《Global Change Biology》2017,23(11):4544-4555
Understanding soil organic carbon (SOC) sequestration is important to develop strategies to increase the SOC stock and, thereby, offset some of the increases in atmospheric carbon dioxide. Although the capacity of soils to store SOC in a stable form is commonly attributed to the fine (clay + fine silt) fraction, the properties of the fine fraction that determine the SOC stabilization capacity are poorly known. The aim of this study was to develop an improved model to estimate the SOC stabilization capacity of Allophanic (Andisols) and non‐Allophanic topsoils (0–15 cm) and, as a case study, to apply the model to predict the sequestration potential of pastoral soils across New Zealand. A quantile (90th) regression model, based on the specific surface area and extractable aluminium (pyrophosphate) content of soils, provided the best prediction of the upper limit of fine fraction carbon (FFC) (i.e. the stabilization capacity), but with different coefficients for Allophanic and non‐Allophanic soils. The carbon (C) saturation deficit was estimated as the difference between the stabilization capacity of individual soils and their current C concentration. For long‐term pastures, the mean saturation deficit of Allophanic soils (20.3 mg C g?1) was greater than that of non‐Allophanic soils (16.3 mg C g?1). The saturation deficit of cropped soils was 1.14–1.89 times that of pasture soils. The sequestration potential of pasture soils ranged from 10 t C ha?1 (Ultic soils) to 42 t C ha?1 (Melanic soils). Although meeting the estimated national soil C sequestration potential (124 Mt C) is unrealistic, improved management practices targeted to those soils with the greatest sequestration potential could contribute significantly to off‐setting New Zealand's greenhouse gas emissions. As the first national‐scale estimate of SOC sequestration potential that encompasses both Allophanic and non‐Allophanic soils, this serves as an informative case study for the international community. 相似文献
15.
在田间定位试验区 ,研究了不同施肥处理对表层红壤性水稻土微团聚体组成以及土壤有机碳在各级微团聚体中分布和赋存的影响。结果表明 ,红壤性水稻土中 0 .0 2～ 0 .0 5 mm微团聚体所占比例最大 ,达 4 0 % ;其次是 0 .0 0 2～ 0 .0 2 mm和 0 .0 5～0 .1mm的微团聚体 ;>0 .2 mm微团聚体占的比例最小。长期施用无机肥 (NPK)、有机肥 (猪粪 紫云英绿肥 ) (OM)、无机肥与有机肥配施 (NPKM) ,能显著增加 0 .0 0 2～ 0 .0 2 mm微团聚体的含量而降低 <0 .0 0 2 m m微团聚体的含量。土壤有机碳含量与0 .0 0 2～ 0 .0 2 mm微团聚体含量之间呈显著正相关关系 ;而与 <0 .0 0 2 mm微团聚体含量呈显著负相关关系。各级微团聚体有机碳含量从高到低顺序为 :>0 .2 mm,0 .1～ 0 .2 mm,<0 .0 0 2 m m,0 .0 5～ 0 .1m m,0 .0 0 2～ 0 .0 2 mm,0 .0 2～ 0 .0 5 m m。 OM、NPKM处理能显著增加 >0 .0 0 2 mm各级微团聚体有机碳的赋存量 ,新增加的有机碳主要向微团聚体 0 .1～ 0 .0 5 m m,0 .0 5～ 0 .0 2 mm和 0 .0 2～ 0 .0 0 2 mm富集 ,它们是土壤有机碳的主要载体。 3种施肥处理对提高土壤有机碳赋存效果高低顺序为 :NPKM>OM>NPK。 相似文献
16.
17.
东北黑土区自开垦以来有机质含量逐渐降低,有机碳库长期处于亏缺状态,理论上也具有较大的固碳潜力。以典型黑土区长期传统作业的坡耕地（30—60 a）为研究对象,通过测定不同坡位（坡上侵蚀区和坡下沉积区）、不同土层（表土和底土）有机碳分布特征,估算不同开垦年限黑土固碳潜力及其恢复至固碳潜力所需的时间。结果表明:（1）总有机碳、有机碳密度以及碳饱和水平均表现为沉积区显著大于侵蚀区,表土显著大于底土,且均在开垦30a坡耕地达到最大值;（2）固碳潜力表现为侵蚀区（1.24—2.89 kg/m2）显著大于沉积区（0.79—1.04 kg/m2）,底土（0.83—3.59 kg/m2）显著大于表土（0.6—2.53 kg/m2）,随着开垦年限的增加表现为开垦30 a显著小于开垦40 a、60 a;（3）黑土坡耕地（30—60 a）侵蚀区和沉积区土壤（0—50 cm）达到固碳潜力分别需要20—181 a和13—66 a。黑土坡耕地固碳潜力的时空变异性在农业经营以及修复管理过程中需引起重视,以实现黑土资源的可持续利用。 相似文献
18.
Meifeng Deng Ping Li Weixing Liu Pengfei Chang Lu Yang Zhenhua Wang Jing Wang Lingli Liu 《Global Change Biology》2023,29(16):4686-4696
Climate-induced changes in snow cover can greatly impact winter soil microclimate and spring water supply. These effects, in turn, can influence plant and microbial activity and the strength of leaching processes, potentially altering the distribution and storage of soil organic carbon (SOC) across different soil depths. However, few studies have examined how changes in snow cover will affect SOC stocks, and even less is known about the impact of snow cover on SOC dynamics along soil profiles. By selecting 11 snow fences along a 570 km climate gradient in Inner Mongolia, covering arid, temperate, and meadow steppes, we measured plant and microbial biomass, community composition, SOC content, and other soil parameters from topsoil to a depth of 60 cm. We found that deepened snow increased aboveground and belowground plant biomass, as well as microbial biomass. Plant and microbial carbon input were positively correlated with grassland SOC stocks. More importantly, we found that deepened snow altered SOC distribution along vertical soil profiles. The increase in SOC caused by deepened snow was much greater in the subsoil (+74.7%; 40–60 cm) than that in the topsoil (+19.0%; 0–5 cm). Additionally, the controls on SOC content under deepened snow differed between the topsoil and subsoil layers. The increase in microbial and root biomass jointly enhanced topsoil C accumulation, while the increase in leaching processes became critical in promoting subsoil C accumulation. We conclude that under deepened snow, the subsoil had a high capacity to sink C by incorporating C leached from the topsoil, suggesting that the subsoil, originally thought to be climate insensitive, could have a higher response to precipitation changes due to vertical C transport. Our study highlights the importance of considering soil depth when assessing the impacts of snow cover changes on SOC dynamics. 相似文献
19.
Susan E. Ward Simon M. Smart Helen Quirk Jerry R. B. Tallowin Simon R. Mortimer Robert S. Shiel Andrew Wilby Richard D. Bardgett 《Global Change Biology》2016,22(8):2929-2938
The importance of managing land to optimize carbon sequestration for climate change mitigation is widely recognized, with grasslands being identified as having the potential to sequester additional carbon. However, most soil carbon inventories only consider surface soils, and most large‐scale surveys group ecosystems into broad habitats without considering management intensity. Consequently, little is known about the quantity of deep soil carbon and its sensitivity to management. From a nationwide survey of grassland soils to 1 m depth, we show that carbon in grassland soils is vulnerable to management and that these management effects can be detected to considerable depth down the soil profile, albeit at decreasing significance with depth. Carbon concentrations in soil decreased as management intensity increased, but greatest soil carbon stocks (accounting for bulk density differences), were at intermediate levels of management. Our study also highlights the considerable amounts of carbon in subsurface soil below 30 cm, which is missed by standard carbon inventories. We estimate grassland soil carbon in Great Britain to be 2097 Tg C to a depth of 1 m, with ~60% of this carbon being below 30 cm. Total stocks of soil carbon (t ha?1) to 1 m depth were 10.7% greater at intermediate relative to intensive management, which equates to 10.1 t ha?1 in surface soils (0–30 cm), and 13.7 t ha?1 in soils from 30 to 100 cm depth. Our findings highlight the existence of substantial carbon stocks at depth in grassland soils that are sensitive to management. This is of high relevance globally, given the extent of land cover and large stocks of carbon held in temperate managed grasslands. Our findings have implications for the future management of grasslands for carbon storage and climate mitigation, and for global carbon models which do not currently account for changes in soil carbon to depth with management. 相似文献