scholarly journals Radiocarbon and Stable Carbon Isotopes in Two Soil Profiles from Northeast India

Radiocarbon ◽  
2012 ◽  
Vol 54 (01) ◽  
pp. 81-89 ◽  
Author(s):  
Amzad H Laskar ◽  
M G Yadava ◽  
R Ramesh
Keyword(s):  
Organic Carbon ◽  
Stable Carbon Isotopes ◽  
Agricultural Land ◽  
Clay Content ◽  
Carbon Dynamics ◽  
Northeast India ◽  
Turnover Time ◽  
Soil Profiles ◽  
The Mean ◽  
Surface Vegetation

Two soil profiles from northeast India, one from Bakrihawar, an agricultural land, and the other from Chandipur, a virgin hilly area from Assam, are investigated to understand the organic carbon dynamics of the area. Due to frequent flooding, the Bakrihawar soil has accumulated a higher clay content than that of Chandipur. The carbon content is less than 1% by weight in both the sites. The higher clay content is responsible for relatively more soil organic carbon at Bakrihawar. The mean δ13C values at both sites reflect the values of the overlying vegetation. At Bakrihawar, both rice cultivation (C3) and natural C4grasses contribute to higher mean enriched values of13C relative to Chandipur, where the surface vegetation is mostly of C3type. The turnover time of organic carbon, estimated using the residual radiocarbon content, depends strongly on the soil particle size distribution, especially the clay content (i.e. it increases with clay content). To the best of our knowledge, this is the first soil carbon dynamics study of its kind from northeast India.

scholarly journals Radiocarbon and Stable Carbon Isotopes in Two Soil Profiles from Northeast India

Radiocarbon ◽  
2012 ◽  
Vol 54 (1) ◽  
pp. 81-89 ◽  
Author(s):  
Amzad H Laskar ◽  
M G Yadava ◽  
R Ramesh
Keyword(s):  
Organic Carbon ◽  
Stable Carbon Isotopes ◽  
Agricultural Land ◽  
Clay Content ◽  
Carbon Dynamics ◽  
Northeast India ◽  
Turnover Time ◽  
Soil Profiles ◽  
The Mean ◽  
Surface Vegetation

Two soil profiles from northeast India, one from Bakrihawar, an agricultural land, and the other from Chandipur, a virgin hilly area from Assam, are investigated to understand the organic carbon dynamics of the area. Due to frequent flooding, the Bakrihawar soil has accumulated a higher clay content than that of Chandipur. The carbon content is less than 1% by weight in both the sites. The higher clay content is responsible for relatively more soil organic carbon at Bakrihawar. The mean δ13C values at both sites reflect the values of the overlying vegetation. At Bakrihawar, both rice cultivation (C3) and natural C4 grasses contribute to higher mean enriched values of 13C relative to Chandipur, where the surface vegetation is mostly of C3 type. The turnover time of organic carbon, estimated using the residual radiocarbon content, depends strongly on the soil particle size distribution, especially the clay content (i.e. it increases with clay content). To the best of our knowledge, this is the first soil carbon dynamics study of its kind from northeast India.

scholarly journals Soil Organic Carbon Stocks in Afforested Agricultural Land in Lithuanian Hemiboreal Forest Zone

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1562
Author(s):  
Iveta Varnagirytė-Kabašinskienė ◽  
Povilas Žemaitis ◽  
Kęstutis Armolaitis ◽  
Vidas Stakėnas ◽  
Gintautas Urbaitis
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Forest Floor ◽  
Agricultural Land ◽  
Forest Stand ◽  
Stand Age ◽  
Soc Stock ◽  
The Mean ◽  
Soc Stocks ◽  
Topsoil Layer

In the context of the specificity of soil organic carbon (SOC) storage in afforested land, nutrient-poor Arenosols and nutrient-rich Luvisols after afforestation with coniferous and deciduous tree species were studied in comparison to the same soils of croplands and grasslands. This study analysed the changes in SOC stock up to 30 years after afforestation of agricultural land in Lithuania, representing the cool temperate moist climate region of Europe. The SOC stocks were evaluated by applying the paired-site design. The mean mass and SOC stocks of the forest floor in afforested Arenosols increased more than in Luvisols. Almost twice as much forest floor mass was observed in coniferous than in deciduous stands 2–3 decades after afforestation. The mean bulk density of fine (<2 mm) soil in the 0–30 cm mineral topsoil layer of croplands was higher than in afforested sites and grasslands. The clear decreasing trend in mean bulk density due to forest stand age with the lowest values in the 21–30-year-old stands was found in afforested Luvisols. In contrast, the SOC concentrations in the 0–30 cm mineral topsoil layer, especially in Luvisols afforested with coniferous species, showed an increasing trend due to the influence of stand age. The mean SOC values in the 0–30 cm mineral topsoil layer of Arenosols and Luvisols during the 30 years after afforestation did not significantly differ from the adjacent croplands or grasslands. The mean SOC stock slightly increased with the forest stand age in Luvisols; however, the highest mean SOC stock was detected in the grasslands. In the Arenosols, there was higher SOC accumulation in the forest floor with increasing stand age than in the Luvisols, while the proportion of SOC stocks in mineral topsoil layers was similar and more comparable to grasslands. These findings suggest encouragement of afforestation of former agricultural land under the current climate and soil characteristics in the region, but the conversion of perennial grasslands to forest land should be done with caution.

Soil texture controls vegetation biomass and organic carbon storage in arid desert grassland in the middle of Hexi Corridor region in Northwest China

Soil Research ◽  
2015 ◽  
Vol 53 (4) ◽  
pp. 366 ◽  
Author(s):  
Yongzhong Su ◽  
Jiuqiang Wang ◽  
Rong Yang ◽  
Xiao Yang ◽  
Guiping Fan
Keyword(s):  
Organic Carbon ◽  
Soil Texture ◽  
Clay Content ◽  
Northwest China ◽  
Hexi Corridor ◽  
Desert Grassland ◽  
Vegetation Biomass ◽  
Below Ground ◽  
The Mean ◽  
Arid Desert

Soil texture plays an important role in controlling vegetation production and soil organic carbon (SOC) concentration in arid desert grassland ecosystems. However, little is known about the occurrence and extent of these textural effects in the arid desert grasslands of Northwest China. This study used 160 soil profiles taken from 32 desert grassland sites in similar topographical units (alluvial–diluvial fans) in the middle of Hexi Corridor region of Northwest China to investigate vegetation biomass, SOC storage, and soil texture of seven layers in the top 100 cm of soil. The mean aboveground biomass, below-ground biomass, and total biomass in arid desert grassland were 155.3, 95.3, and 256.3 g m–2, respectively. More than 95% of the below-ground biomass was distributed in the top 30 cm of soil. Spatially, vegetation biomass was positively related to soil clay content and silt + clay content. The mean SOC density in the top 100 cm was 2.94 kg m–2 and ~46.8% of the storage was concentrated in the top 30 cm. SOC concentrations and stocks were positively and significantly related to clay content and silt + clay content in the seven soil layers sampled from the top 100 cm. The soil silt + clay content explained 42–79% of the variation in SOC stocks in the different soil depths. In conclusion, soil texture appears to be an important control on vegetation productivity and SOC capacity in arid Hexi Corridor desert grassland soils.

scholarly journals Distribution and Sources of Organic Carbon in Surface Intertidal Sediments of the Rudong Coast, Jiangsu Province, China

2021 ◽  
Vol 9 (9) ◽  
pp. 992
Author(s):  
Yinan Mao ◽  
Qingyun Ma ◽  
Jiaxin Lin ◽  
Ye Chen ◽  
Qiang Shu
Keyword(s):  
Organic Carbon ◽  
Tidal Flat ◽  
Stable Carbon Isotopes ◽  
Mixing Model ◽  
Depositional Environments ◽  
Stable Carbon ◽  
Intertidal Sediments ◽  
Δ13c Value ◽  
The Mean ◽  
Tidal Flat Sediments

In this study, total organic carbon (TOC), total nitrogen (TN), and stable carbon isotopes (δ13C) were measured in surface intertidal saltmarsh and bare tidal flat sediments along the Rudong coast. The distribution and sources of organic carbon were examined under different depositional environments based on C/N ratios and a two-terminal mixing model. The results showed that the average TOC content of the vegetated saltmarsh sediments, bare tidal flat areas near vegetation (BF1), and bare tidal flat areas far from vegetation (BF2) were 4.05, 2.72, and 1.22 mg/g, respectively. The mean δ13C value within the vegetated saltmarsh area was −22.37‰, and the C/N ratio was 9.3; the corresponding values in the BF1 area were −23.27‰ and 7.95, respectively; and in the BF2 area, the corresponding values were −21.91‰ and 5.36, respectively. These C/N ratios reflect an increasing marine contribution with distance from the vegetated zone. Combined with the two-terminal mixing model, the organic carbon in the vegetated saltmarsh sediments was dominated by terrestrial sources, while the bare tidal flat sediments were more influenced by marine sources, and the bare tidal flat sediments nearer to the vegetated zone (BF1) were influenced by a combination of vegetation, marine sources, and other terrestrial factors.

scholarly journals Organic Carbon Stocks, Dynamics and Restoration in Relation to Soils of Agroecosystems in Ethiopia: A Review

2017 ◽  
Vol 6 (1) ◽  
pp. 1-22 ◽  
Author(s):  
Getaneh Gebeyehu ◽  
Teshome Soromessa ◽  
Demel Teketay
Keyword(s):  
Organic Carbon ◽  
Agricultural Land ◽  
Farming Systems ◽  
Carbon Stocks ◽  
Land Uses ◽  
Grazing Land ◽  
Measurement And Analysis ◽  
The Mean ◽  
Storage Potential ◽  
Restoration Strategies

Soils represent the largest carbon pool and play important roles for carbon storage for prolonged periods in agroecosystems. A number of studies were conducted to quantify soil organic carbon (SOC) worldwide. The objective of this review was to evaluate organic carbon stocks, dynamics and restoration in soils of agroecosystems in Ethiopia. Soil data from 32 different observations, representing four different agroecosystems, were analysed. The mean SOC stocks in the four agroecosystems varied and ranged from 25.66 (sub-humid agroecosystem) to 113.17 (humid mid-highland agroecosystems) Mg C ha-1 up to one meter depth. The trend of mean SOC followed (in descending order): humid mid-highland (113.17 Mg C ha-1) > per-humid highland (57.14 Mg C ha-1) > semi-arid (25.77 Mg C ha-1) > sub-humid (25.66 Mg C ha-1). Compared with soils of tropical countries, those in Ethiopian agroecosystems contained low SOC storage potential. This might be associated with differences in measurement and analysis methods as 53.1% of the studies employed the Walkley-Black Method, which is known to underestimate carbon stocks in addition to ecological and management effects. However, shifts of land management from rain-fed to irrigation farming systems exhibited progress in the improvement of mean SOC storage potential. The analyses showed that farming systems involving irrigation sequestered more carbon than rain-fed farm systems. The mean SOC in the various agricultural land uses followed the following trend (in descending order): agroforestry (153.57 Mg C ha-1) > grazing land (34.61 Mg C ha-1) > cereal cultivation (24.18 Mg C ha-1). Therefore, the possible solutions for improvement of organic carbon stocks would be implementation of appropriate restoration strategies based on agroecosystems.INTERNATIONAL JOURNAL OF ENVIRONMENT Volume-6, Issue-1, Dec-Feb 2016/17, page: 1-22 

FE STATUS OF BRUNISOLIC AND RELATED SOIL PROFILES

1973 ◽  
Vol 53 (2) ◽  
pp. 185-197 ◽  
Author(s):  
L. E. LUTWICK ◽  
J. F. DORMAAR
Keyword(s):  
Organic Carbon ◽  
Humic Acids ◽  
Clay Content ◽  
Parent Material ◽  
Soil Profiles ◽  
Infrared Absorption Spectroscopy ◽  
Parent Materials ◽  
Hydrous Oxides ◽  
Definition Of ◽  
Product Forms

Three pairs of soil profiles developed on calcareous parent materials and two pairs of soil profiles developed on acidic parent materials were chosen morphologically in the field to represent Brunisolic/Luvisolic and Brunisolic/Podzolic features, respectively. Oxalate-, pyrophosphate-, and dithionite-extractable Fe were determined for each horizon. Also, Fe was partitioned into crystalline, "aged" and "gel" amorphous hydrous oxides, and organic forms. Humic acids extracted from each horizon with alkali were characterized by infrared absorption spectroscopy. Soils developed on acidic parent materials contained more extractable Fe than did those developed on calcareous parent materials. Only one horizon fitted the requirements of the chemical definition of a Bf horizon. All three reagents indicated zones of depletion and accumulation of Fe in soils developed on calcareous parent materials; oxalate and pyrophosphate did but dithionite did not show these relationships for soils developed on acidic parent materials. With exceptions, extractable Fe was correlated with clay content on the soils with calcareous parent material but was correlated with organic carbon on the soils with acidic parent materials. Well-crystallized Fe showed horizon differentiation in soils with calcareous parent materials and is therefore a weathering product. In soils with acidic parent materials, crystallized Fe was the source of weathering product forms of Fe. Humic acids of soils with acidic parent materials were more highly oxidized and hence more capable of reacting with Fe than were those of soils with calcareous parent materials.

scholarly journals Carbon Isotope Dynamics in Some Tropical Soils

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 672-679 ◽  
Author(s):  
Peter Becker-Heidmann ◽  
H-W Scharpenseel
Keyword(s):  
Organic Carbon ◽  
Depth Distribution ◽  
Clay Content ◽  
Distribution Patterns ◽  
Tropical Soils ◽  
Humid Tropics ◽  
Soil Profiles ◽  
Decomposition Of Organic Matter ◽  
C Value ◽  
The Tropics

We determined δ13C and D14C in some agricultural soil profiles of the tropics: Ustalf from the semi-arid tropics (India), a Udult, an Aquoll and an Aquept from the humid tropics (Philippines). We used a thin-layer sampling, resulting in high-resolution depth-distribution patterns of natural 13C and 14C content of organic carbon. Regular plowing or puddling leads to uniform isotope concentrations in the topsoil. Decomposition of organic matter raises the δ13C value, and vertical translocation raises the δ13C value with depth. The change of cultivation from pulses (C3-type metabolism of photosynthesis) to sorghum (C4) results in a decrease of δ13C with depth in the topsoil. Where the clay content in the subsoil is high, δ13C remains constant, due to fixation of organic carbon to clay minerals, and D14C decreases with depth. Below the clay-enriched zone, δ13C declines and D14C rises again, due to a chromatographic-like effect. At some horizon boundaries, inhomogeneities in texture delay percolation locally, thus preventing sorption and causing peak values of D14C.

Soil-Carbonate Genesis in the Pinacate Volcanic Field, Northwestern Sonora, Mexico

1991 ◽  
Vol 35 (3-Part1) ◽  
pp. 400-416 ◽  
Author(s):  
Janet L. Slate ◽  
William B. Bull ◽  
Teh-Lung Ku ◽  
Muhammad Shafiqullah ◽  
Daniel J. Lynch ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Laboratory Data ◽  
Clay Content ◽  
Volcanic Field ◽  
Soil Profiles ◽  
Soluble Salts ◽  
Pedogenic Carbonate ◽  
The Past ◽  
The Mean ◽  
Eolian Deposits

AbstractUranium-series methods were used to date and evaluate pedogenic CaCO3 genesis in the Pinacate volcanic field, northwestern Sonora, Mexico. Soils are developed in eolian deposits on lava flows. 230Th/234U dates of pedogenic carbonate are mininum soil ages because of (1) the time needed to yield clasts from flows and to accrete enough carbonate to sample, (2) subsequent additions of uranium, and (3) continued solution and reprecipitation of carbonate rinds. K-Ar dates of basalt flows are maximum soil ages. Maximum and minimum rates of CaCO3 accumulation are calculated from the Th/U dates and K-Ar dates, respectively. The mean maximum rate is 0.13 g CaCO3/cm2/1000 yr and the mean minimum rate is 0.05 g CaCO3/cm2/1000 yr. Least-squares regressions of pedogenic carbonate and clay content and of Th/U ages against K-Ar ages suggest additions to soils from atmospheric sources throughout the late Quaternary. Morphology of pedogenic carbonate and laboratory data for soluble salts indicate that the climate of the Pinacate has not changed significantly during the past 150,000 yr. Soil variability is influenced by proximity of the eolian source. Near the periphery of the Pinacate, carbonate and clay are evenly distributed throughout soil profiles. Within the volcanic field, carbonate and clay are concentrated in soil horizons, suggesting that additions from atmospheric sources are slow enough to allow translocation.

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