Changes In Organic Carbon Storage Research Articles

Dynamics of structural indices and organic carbon pool across a haplic acrisol under secondary tropical rainforest at Umudike Abia State

Differences in vegetation types over a landscape influences the structural behaviour and organic carbon pool of soils thereby affecting site-specific management decisions. This study aimed at establishing the differences in structural indices and organic carbon pool across a soil under secondary rainforest vegetation. Nine replicates of auger and core soil samples were randomly collected from the site at 0 – 20 cm depth. Soil samples were prepared and analysed at a laboratory. Data obtained were subjected to geospatial analysis using a Geographical Information System (GIS) software package. Results showed that changes in organic carbon storage ranged from 40 – 48 ton / ha, BD ranged from 1.39 – 1.42 mg / m3, clay flocculation index ranged from 50 – 68 %, aggregated silt + clay ranged from 9 – 12 %, clay dispersion index ranged from 32 – 42 %, dispersion ratio ranged from 26 – 32 %, mean weight diameter ranged from 0.75 – 1.05 mm, saturated hydraulic conductivity ranged from 3.1 – 3.8 cm / mins and total porosity ranged from 46.4 – 47.6 %. Regions of weak micro aggregaion dominated the land while regions of increased stability of macro aggregates were dominant. Regions of increased soil organic carbon storage occupied about half portion of the land. Greater portion of the land was noted for increased bulk density, reduced total porosity and saturated hydraulic conductivity. Consequently, there were changes in soil structural properties and organic carbon storage across the studied area.

Vertical Changes of Organic Carbon Storage, Structural and Hydraulic Properties of a Humid Tropical Soil under Vegetation Cover in Southeast Nigeria

Changes in organic carbon storage (OCS), structural and hydraulic properties with depth of soil are important phenomena that need to be understood per soil for effective soil management in crop production. A study was conducted in a Randomized Complete Block Design (RCBD) to assess the vertical changes in OCS, structural and hydraulic properties of soil under vegetation cover. The study involved 5 levels of sampling depth replicated nine (9) times to give forty five (45) observational units. The nine points for sampling were randomly selected and the five sampling depths were 0 – 20, 20 – 40, 40 – 60, 60 – 80 and 80 – 100 cm. Auger and core soil samples were collected at the designated depths. The samples were processed and analysed in the laboratory. The results of data analyses showed that depths varied significantly (P≤0.05) in the parameters measured. The highest OCS of 38.28 ton / ha was obtained at the 0 – 20 cm depth and the lowest (10.38 ton / ha) was obtained at 80 – 100 cm depth. The highest mean weight diameter of 1.00 mm and lowest of 0.72 mm were obtained at 0 – 20 and 80 – 100 cm depths, respectively. The lowest clay dispersion index of 25.43 % and the highest clay flocculation index of 74.53 % were obtained at 80 – 100 cm depth. Clay content and bulk density (BD) increased with depth and, the highest clay content of 212.4 g / kg and highest BD of 1.65 mg / m3 were obtained at the 80 – 100 cm depth. Saturated hydraulic conductivity (Ksat), total porosity (Pt) and macroporosity (Pm) decreased with depth. The highest Ksat of 3.11 cm / hr, Pt of 47.41 % and Pm of 24.13 % were obtained at 0 – 20 cm depth. The water retention characteristics increased with depth. The highest field capacity of 24.46 %, permanent wilting point of 11.16 % and available water capacity of 13.32 % were obtained at 80 – 100 cm depth. There were consistent changes in the soil properties across the depths. The reduced drainage at the higher depths should be considered in cultivating deep rooted crops which are sensitive to poor drainage. The top soils should be managed with good agronomic practices and minimum tillage to avert damages to the microaggregates.

Immediate and long-term effects of tillage practices with crop residue on soil water and organic carbon storage changes under a wheat-maize cropping system

Reasonable tillage management benefits soil structure optimization and agricultural sustainability. However, the differences of immediate (i.e. changes between post- and pre- tillage) and long-term effects (i.e. changes between treatments after certain years) under different tillage practices is often neglected. This study involved a 16-year field experiment including three tillage practices (plow tillage, PT; subsoiling tillage, ST and rotary tillage, RT) and two crop residue management practices (no residue return and all residue return). Those immediate and long-term effects on soil physical properties and soil organic carbon were investigated. For the immediate effects after tillage, the soil water storage under PT, ST, and RT decreased by 5.8%, 4.0%, and 3.2%, respectively; while those under residue return and no residue return decreased by 3.9% and 4.6%, respectively. Under the same conditions, ST was more beneficial to reduce soil penetration resistance. The soil bulk density post-tillage was significantly lower than that pre-tillage at 0–10 cm soil depth, meanwhile the soil bulk density at 10–40 cm soil depth was generally decreased after tillage practice under ST treatment. For the long-term effects, the penetration resistance at 10–50 cm soil depth and the soil bulk density at 10–30 cm soil depth were lower under the ST treatment than those under PT and RT treatments. Additionally, residue return was beneficial for soil water storage, soil bulk density, and soil organic carbon storage. Overall, both for the immediate and long-term effects, subsoiling tillage with residue return significantly increased soil water storage, total porosity, soil organic carbon storage and crop yields, while decreased soil bulk density and penetration resistance.

Impacts of mulching measures on crop production and soil organic carbon storage in a rainfed farmland area under future climate

Mulch planting techniques are used widely to increase the crop yield in the Loess Plateau region of China. However, the impacts of long-term mulching measures on crop productivity and soil organic carbon (SOC) storage under climate change are still unclear. In this study, the denitrification-decomposition (DNDC) biogeochemistry model was calibrated based on field test data from 2013 to 2018, and the downscaling predicted climate data from 33 Global Climate Models (GCMs) were used to assess the future trends in spring maize yield and soil organic carbon storage changes under different mulching tillage measures (i: conventional tillage without mulching as the control (CK); ii ridge–furrow planting with half plastic film mulching (R); iii: straw mulching (S); iv: dual mulching of the ridge (film) and furrow (straw) (RS)) in the Loess Plateau region. The results showed that the precipitation and temperature will increase in the future (2021–2100), especially under RCP8.5. Similarly, crop productivity has been more substantial increase under RCP8.5. Under both scenarios, the predicted yield increase under each treatment was greater in the early period than the later period, and the RS treatment obtained the largest increase. However, when the annual precipitation exceeded 600 mm, the yield increase was not significant under R. Sensitivity analysis showed that ridge and furrow mulching measures reduced the sensitivity of the yield to precipitation changes. In the future, SOC storage increased slightly with both CK and R under RCP4.5, but both showed a downward trend under RCP8.5, respectively. R treatment showed a lower temperature threshold, and when the temperature was increased above 9.60 °C, the carbon loss rate accelerated. Under S and RS, the SOC storage tended to increase due to straw mulching. All these results indicated that in the future period, when the annual precipitation exceeded 600 mm and the annual average temperature exceeded 9.60 °C, ridge-furrow plastic film mulching was not suitable in this area, dual mulching of the ridge with film and furrow with straw may help to achieve sustainable high maize yields in the Loess Plateau region.

Spatial Expansion and Soil Organic Carbon Storage Changes of Croplands in the Sanjiang Plain, China

Soil is the largest pool of terrestrial organic carbon in the biosphere and interacts strongly with the atmosphere, climate and land cover. Remote sensing (RS) and geographic information systems (GIS) were used to study the spatio-temporal dynamics of croplands and soil organic carbon density (SOCD) in the Sanjiang Plain, to estimate soil organic carbon (SOC) storage. Results show that croplands increased with 10,600.68 km2 from 1992 to 2012 in the Sanjiang Plain. Area of 13,959.43 km2 of dry farmlands were converted into paddy fields. Cropland SOC storage is estimated to be 1.29 ± 0.27 Pg C (1 Pg = 103 Tg = 1015 g) in 2012. Although the mean value of SOCD for croplands decreased from 1992 to 2012, the SOC storage of croplands in the top 1 m in the Sanjiang Plain increased by 70 Tg C (1220 to 1290). This is attributed to the area increases of cropland. The SOCD of paddy fields was higher and decreased more slowly than that of dry farmlands from 1992 to 2012. Conversion between dry farmlands and paddy fields and the agricultural reclamation from natural land-use types significantly affect the spatio-temporal patterns of cropland SOCD in the Sanjiang Plain. Regions with higher and lower SOCD values move northeast and westward, respectively, which is almost consistent with the movement direction of centroids for paddy fields and dry farmlands in the study area. Therefore, these results were verified. SOC storages in dry farmlands decreased by 17.5 Tg·year−1 from 1992 to 2012, whilst paddy fields increased by 21.0 Tg·C·year−1.

Soil Organic Carbon Storage Changes in Coastal Wetlands of the Liaohe Delta, China, Based on Landscape Patterns

Growing wetland loss along a coastal area in China was examined through shoreline recession and land use changes. Carbon storage or sequestration in coastal wetland soils was based on vertical marsh accretion and aerial change data. Marshes sequester significant amounts of carbon through vertical accretion; however, large amounts of carbon previously sequestered in the soil profile are lost through rapid land use changes and shoreline recessions. The Liaohe Delta (LHD) was divided into nine landscape types based on Landsat TM digital images from 1991 to 2011. The distributed areas and transfer matrices of each landscape type were calculated. Combined with the organic carbon content and bulk density of 202 soil surface samples from field investigations in 2012, the soil organic carbon pools and stocks were estimated. Results showed that the soil organic carbon pools varied from 0.58 to 9.75 kg m−2, and organic carbon storage in the upper 20 cm of soil was 1935.92 × 104 and 1863.87 × 104 t in 1991 and 2011, respectively. We attributed these large losses of carbon to rapid land use changes. The construction of levees along the shoreline has triggered large instantaneous losses of previously sequestered carbon through the destruction of 278.06 km2 of tidal flats. Our results reveal that the LHD wetlands might not serve as a desired sink of carbon if maladministration practices are applied. These results can provide scientific guidance for decision makers in determining an effective way to maintain the soil carbon pool in the wetlands of the LHD.

秦岭南坡红桦林土壤有机碳密度影响因素

PDF HTML阅读 XML下载 导出引用 引用提醒 秦岭南坡红桦林土壤有机碳密度影响因素 DOI: 10.5846/stxb201406271326 作者: 作者单位: 西北农林科技大学林学院,西北农林科技大学林学院,西北农林科技大学林学院,西北农林科技大学林学院 作者简介: 通讯作者: 中图分类号: 基金项目: 林业公益性行业科研专项项目(201204502) Factors affecting soil organic carbon density in Betula albo-sinensis forests on the southern slope of the Qinling Mountains Author: Affiliation: College of Forestry,Northwest A&F University,Yangling,College of Forestry,Northwest A&F University,Yangling,College of Forestry,Northwest A&F University,Yangling,College of Forestry,Northwest A&F University,Yangling Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以秦岭南坡红桦林为研究对象,利用标准地调查法获得林分、地形、土壤相关数据,分析红桦林土壤有机碳密度(SOCD)分异特征及其与林分因子和地形因子间的关系。结果表明:秦岭南坡红桦林土壤有机碳密度总体均值为(69.02±12.90)t/hm2,原始红桦林土壤有机碳密度均值为(76.21±10.83)t/hm2,次生红桦林为(65.24±12.32)t/hm2,原始红桦林土壤有机碳密度比次生红桦林高16.81%,t-检验结果显示两者存在显著差异;在不同林区间,红桦林土壤有机碳密度亦存在显著差异(P < 0.05)。从地形因子看,红桦林土壤有机碳密度在不同坡位和坡向间未表现出显著差异,而海拔和坡度对红桦林土壤有机碳密度有较为显著的影响。土壤有机碳密度与海拔、林龄、乔木生物量和草本生物量呈显著正相关,与坡度和林分密度呈显著负相关;主成分分析表明:特征值大于1的四个主成分对土壤有机碳密度的方差累积贡献率为85.62%,海拔、坡度、林分密度和郁闭度是影响秦岭南坡红桦林土壤有机碳密度的主要因子;通过逐步回归分析得到利用海拔、坡度、林龄、林分密度、乔木生物量和草本生物量估算红桦林土壤有机碳密度的模型:SOCD=0.015E-0.332G-0.026FD+0.304SA+0.105BA+21.673BH+36.358。 Abstract:Soil organic carbon, the main part of the terrestrial ecosystem carbon pool, is an essential component of the terrestrial carbon cycle, and one of the most important components of research on global change. Accurate estimation of soil organic carbon storage is important for determining the role that soil organic carbon plays in the terrestrial ecosystem carbon cycle, and thus in changes in the global environment. Forest soil organic carbon storage changes according to topography and forest conditions; therefore, research on forest organic carbon in a variety of such conditions is essential to determine the relationship between soil organic carbon storage, and factors related to topography and forest conditions. Betula albo-sinensis forest is one of the principal forest types in the Qinling Mountains. This study aimed to analyze the distribution patterns of soil organic carbon density (SOCD), and to reveal the relationship between soil organic carbon density and factors influencing Betula albo-sinensis forest on the southern slopes of the Qinling Mountains. We investigated topographical, stand, and soil factors of 122 plots, each of which was 20×30 m. Inventory data (i.e., elevation, gradient, slope position, slope aspect, canopy density, plant cover, biomass, mean height, and mean diameter at breast height) of Betula albo-sinensis individuals in each plot were measured and recorded. Soil samples were tested for SOCD, moisture density, and bulk density. Results indicated that the average SOCD was (69.02±12.90) t/hm2. In virgin forest, the average SOCD was (76.21±10.83) t/hm2, in secondary forest, (65.24±12.32) t/hm2. The difference in average SOCD between them was significant. The average SOCD decreased with soil depth increasing, and the average SOCD for soil layers A-C was (31.52±6.57), (27.18±6.49), and (10.32±2.65) t/hm2, respectively. The average SOCD (t/hm2) differed by forest region (Xunyangba=(58.80±10.29), Huoditang=(67.95±10.25), Huangbaiyuan=(69.63±12.78), and Guanyinshan=(75.82±12.30)). One-way ANOVA analysis showed that differences in average SOCD were significant for the four forest regions and soil layers, but not significant for slope positions. Differences in SOCD between shady and sunny slopes were insignificant, based on t-tests. Correlation analysis showed that SOCD was positively correlated with elevation, stand age, arbor biomass, and herb biomass, but negatively correlated with surface gradient and forest density. Principal component analysis showed that elevation and gradient were the first principal components affecting SOCD. Canopy density and forest density were the second principal components, stand age the third, and arbor biomass and herb biomass the fourth. These four principal components accounted for 85.62% of the variance of SOCD. Stepwise regression analysis showed that the effect of different factors on soil organic carbon density was unclear. However, stand age, elevation, gradient, arbor biomass, and herb biomass were the predominant factors affecting SOCD. 参考文献 相似文献 引证文献

Soil organic carbon storage changes in coastal wetlands of the modern Yellow River Delta from 2000 to 2009

Abstract. Soil carbon sequestration plays an essential role in mitigating atmospheric CO2 increases and the subsequently global greenhouse effect. The storages and dynamics of soil organic carbon (SOC) of 0–30 cm soil depth in different landscape types including beaches, reservoir and pond, reed wetland, forest wetland, bush wetland, farmland, building land, bare land (severe saline land) and salt field in the modern Yellow River Delta (YRD) were studied based on the data of the regional survey and laboratory analysis. The landscape types were classified by the interpretation of remote sensing images of 2000 and 2009, which were calibrated by field survey results. The results revealed an increase of 10.59 km2 in the modem YRD area from 2000 to 2009. The SOC density varied ranging from 0.73 kg m−2 to 4.25 kg m−2 at depth of 0–30 cm. There were approx. 3.559 × 106 t and 3.545 × 106 t SOC stored in the YRD in 2000 and 2009, respectively. The SOC storages changed greatly in beaches, bush wetland, farm land and salt field which were affected dominantly by anthropogenic activities. The area of the YRD increased greatly within 10 years, however, the small increase of SOC storage in the region was observed due to landscape changes, indicating that the modern YRD was a potential carbon sink and anthropogenic activity was a key factor for SOC change.

Soil organic carbon storage changes in Yangtze Delta region, China

Soil carbon sequestration plays an essential role in mitigating CO2 increases and the global greenhouse effect. This paper calculates soil organic carbon (SOC) storage changes during the course of industrialization and urbanization in Yangtze Delta region, China, based on the data of the second national soil survey (1982–1985) and the regional geochemical survey (2002–2005), with the help of remote sensing images acquired in periods of 1980, 2000, 2005. The results show that soils in the top 0–20 and 0–100 cm depth in this region demonstrate the carbon sink effect from the early 1980s to the early 2000s. The SOC storage in 0–20 cm depth has resulted in increase from 213.70 to 238.65 Tg, which corresponds to the SOC density increase from 2.94 ± 1.08 to 3.28 ± 0.92 kg m−2, and mean carbon sequestration storage and rate are 1.25 Tg a−1, 17.14 g m−2 a−1, respectively. The SOC storage in 0–100 cm depth has resulted in increase from 690.26 to 792.65 Tg, which corresponds to the SOC density increase from 9.48 ± 4.22 to 10.89 ± 3.42 kg m−2, and mean carbon sequestration storage and rate are 5.12 Tg a−1, 70.32 g m−2 a−1, respectively. Urban area in Yangtze Delta region, China, increased more than 3,000 km2 and the urban growth patterns circled the central city region in the past 20 years. The SOC densities in 0–20 cm depth decrease gradually along urban–suburban–countryside and the urban topsoil is slightly enriched with SOC. Compared to the data of the second national soil survey in the early 1980s, the mean SOC density in urban area increased by 0.76 kg m2, or up 25.85% in the past 20 years. With the characteristics of SOC storage changes offered, land-use changes, farming system transition and ecological city construction are mainly attributed to SOC storage increases. Because of lower SOC content in this region, it is assumed that the carbon sink effect will go on in the future through improved soil management.

Soil organic carbon storage changes with climate change, landform and land use conditions in Garhwal hills of the Indian Himalayan mountains

The Indian Himalayan mountain region is predominantly under forest cover with soils having high organic carbon content. In the past few decades significant changes in climate and land use have caused Soil Organic Carbon (SOC) depletion leading to a declining trend in productivity. An improved understanding of these factors will be helpful in preventing further loss of organic carbon from these soils. This study was undertaken to evaluate the influence of climate and land use on SOC in the Indian Himalayan region. SOC storage in the soils of different landforms was estimated for 1978 and 2004. Rainfall and temperature data of the past 50 years were analyzed and it was found that rainfall has declined by 46 per cent and the maximum rainfall-receiving months shifted from June–July to August–September. The mean annual air temperature also increased during this period. The decline in rainfall and the rise in diurnal temperatures caused glacial retreat in terms of snow covered area by nearly 5 per cent during these years. The rise in mean minimum temperature by 1.6 °C and mean monthly temperature by 1.3 °C and changes in land use have significantly reduced soil organic carbon content in the soils of different landforms. The average decrease was 0.3 per cent in different land units when compared to the base year 1978. The maximum decline was observed in soils on landforms with a higher percent slope. The SOC storage was significantly higher on hilltops (31.7–42.4 kg m −2) as compared to hillside slopes (13.5–34.7 kg m −2). The SOC was significantly lower in valleys and piedmonts due to the higher temperature in valleys and the intensive agriculture causing higher mineralization of SOC in soils. Influence of altitude and climate was more predominant than vegetation type and landform at higher altitudes (>1700 m a.s.l.) than at lower altitudes (900–1700 m a.s.l). Significantly, higher carbon storage was estimated in soils under Rhododendron and Quercus forests as compared to those under pine forests having similar slopes and altitudes. The carbon storage at 0–0.15, 0–0.3 and 0–1.5 m depths in different physiographic situations revealed that carbon accumulation and its movement in the soil profile are influenced by the combined impact of climate, altitude, and land use under the given physiographic situation. This study also suggests the need for further investigations using geospatial techniques and spatial data on regional scales because input data for simulation models to measure SOC changes over time in natural ecosystems is influenced by vegetation, crops, landforms and climate under natural ecosystems.

Changes in organic carbon storage in a 50 year white spruce plantation chronosequence established on fallow land in Quebec

The objectives of this study were to assess the change in organic carbon (C) stocks in aboveground biomass, litter, and soil in a 50 year chronosequence of white spruce (Picea glauca (Moench) Voss) plantations established on non-regenerated fallow land in Quebec, and to determine the effects of ploughing (furrows) on these C stocks. Woody aboveground biomass was determined from dendrometric surveys and the use of allometric equations. The litter was sampled as well as the underlying soil in layers 10 cm thick down to 50 cm depth. The plantations under study were C sinks over the 50 year period, since they accumulated 75 Mg·ha–1 during this period, with the highest rate of C accumulation occurring in the woody aboveground vegetation between 10 and 35 years. The soil at 0–30 cm depth was a C source, mainly until the plantations reached 22 years of age, with an annual loss of 0.8% over 50 years. No difference was observed among the controls and site-preparation treatments. These results suggest that 22-year-old white spruce plantations, the oldest considered for the first commitment period of the Kyoto Protocol (2008–2012), would be a small C sink (12 Mg·ha–1) in southeastern Quebec but would become a larger sink for subsequent commitment periods.

Increased sequestration of organic carbon in soil by hydrophobic protection

The impact of soil organic carbon dynamics on the global carbon cycle is still largely uncertain despite studies of agricultural activities and control emissions of greenhouse gases to the earth's atmosphere. Improved knowledge of organic matter dynamics should lead to reduction in CO(2 )emissions. We used stable carbon isotope analysis to detect small changes in organic carbon storage and turnover upon soil treatments with a (13)C-labeled aliphatic alcohol previously partitioned into soluble humic substances of varying hydrophobicity. We found that labeled organic carbon is increasingly protected from mineralization with increased hydrophobic character of humic matter. The stabilization of organic carbon by hydrophobic protection significantly reduced decomposition during incubation time in soil. Hydrophobic protection can become an useful tool to limit decomposition of fresh organic matter in soil and thus reduce CO(2) emission from agricultural soils on a global scale.http://link. springer.de/link/service/journals/00114/bibs/9086010/90860496. htm</HEA