scholarly journals Spatial heterogeneity and environmental predictors of permafrost region soil organic carbon stocks

2021 ◽  
Vol 7 (9) ◽  
pp. eaaz5236 ◽  
Author(s):  
Umakant Mishra ◽  
Gustaf Hugelius ◽  
Eitan Shelef ◽  
Yuanhe Yang ◽  
Jens Strauss ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Spatial Heterogeneity ◽  
Surface Air Temperature ◽  
Spatially Explicit ◽  
Soil Profiles ◽  
Permafrost Region ◽  
Environmental Predictors ◽  
Soil Organic Carbon Stocks ◽  
Soc Stocks

Large stocks of soil organic carbon (SOC) have accumulated in the Northern Hemisphere permafrost region, but their current amounts and future fate remain uncertain. By analyzing dataset combining >2700 soil profiles with environmental variables in a geospatial framework, we generated spatially explicit estimates of permafrost-region SOC stocks, quantified spatial heterogeneity, and identified key environmental predictors. We estimated that 1014−175+194 Pg C are stored in the top 3 m of permafrost region soils. The greatest uncertainties occurred in circumpolar toe-slope positions and in flat areas of the Tibetan region. We found that soil wetness index and elevation are the dominant topographic controllers and surface air temperature (circumpolar region) and precipitation (Tibetan region) are significant climatic controllers of SOC stocks. Our results provide first high-resolution geospatial assessment of permafrost region SOC stocks and their relationships with environmental factors, which are crucial for modeling the response of permafrost affected soils to changing climate.

scholarly journals Soil organic carbon stocks in relation to the altitude in Serbia

2021 ◽  
Vol 70 (1) ◽  
pp. 102-116
Author(s):  
Dragana Vidojević ◽  
Maja Manojlović ◽  
Aleksandar Đorđević ◽  
Radovan Savić ◽  
Ljiljana Nešić ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Statistical Correlation ◽  
Carbon Stocks ◽  
Statistical Dependence ◽  
Soil Profiles ◽  
Mean Values ◽  
Soil Organic Carbon Stocks ◽  
The Relationship ◽  
Soc Stocks

The research was conducted to determine the soil organic carbon (SOC) stocks in relation to the altitude in Serbia. The database included a total of 1,140 soil profiles. SOC were investigated at different the altitudes (0-200 m, 200-500 m, 500-1,000 m, 1,000 - 2.000 m) and at two soil depths (0-30 cm and 0-100 cm). Statistical correlation was done for five regions where locations were grouped according to the spatial distribution. The results showed that the highest mean values of SOC were measured on the terrain that includes mountains with the altitudes of 1,000-2,000 m and covers an area of 11.5% of the territory of Serbia. The lowest obtained result is related to the lowland areas with the largest number of locations. Greater variability in the results of SOC stocks were found at the higher altitudes and the greatest on the low mountains of 500-1,000 m altitude. There is a medium to strong statistical dependence of the altitude with the SOC stocks at two soil depths (0-30 cm and 0-100 cm). The result indicate that the relationship between SOC stocks and altitude varies between the regions. This study shows that altitude is an important factor affecting SOC stocks.

scholarly journals Estimating soil organic carbon stocks of Swiss forest soils by robust external-drift kriging

2014 ◽  
Vol 7 (3) ◽  
pp. 1197-1210 ◽  
Author(s):  
M. Nussbaum ◽  
A. Papritz ◽  
A. Baltensweiler ◽  
L. Walthert
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Near Infrared ◽  
Likelihood Method ◽  
Standard Errors ◽  
Soil Profiles ◽  
Near Infrared Reflectance ◽  
Soc Stock ◽  
Soc Stocks ◽  
External Drift

Abstract. Accurate estimates of soil organic carbon (SOC) stocks are required to quantify carbon sources and sinks caused by land use change at national scale. This study presents a novel robust kriging method to precisely estimate regional and national mean SOC stocks, along with truthful standard errors. We used this new approach to estimate mean forest SOC stock for Switzerland and for its five main ecoregions. Using data of 1033 forest soil profiles, we modelled stocks of two compartments (0–30, 0–100 cm depth) of mineral soils. Log-normal regression models that accounted for correlation between SOC stocks and environmental covariates and residual (spatial) auto-correlation were fitted by a newly developed robust restricted maximum likelihood method, which is insensitive to outliers in the data. Precipitation, near-infrared reflectance, topographic and aggregated information of a soil and a geotechnical map were retained in the models. Both models showed weak but significant residual autocorrelation. The predictive power of the fitted models, evaluated by comparing predictions with independent data of 175 soil profiles, was moderate (robust R2 = 0.34 for SOC stock in 0–30 cm and R2 = 0.40 in 0–100 cm). Prediction standard errors (SE), validated by comparing point prediction intervals with data, proved to be conservative. Using the fitted models, we mapped forest SOC stock by robust external-drift point kriging at high resolution across Switzerland. Predicted mean stocks in 0–30 and 0–100 cm depth were equal to 7.99 kg m−2 (SE 0.15 kg m−2) and 12.58 kg m−2 (SE 0.24 kg m−2), respectively. Hence, topsoils store about 64% of SOC stocks down to 100 cm depth. Previous studies underestimated SOC stocks of topsoil slightly and those of subsoils strongly. The comparison further revealed that our estimates have substantially smaller SE than previous estimates.

scholarly journals Soil organic carbon stocks are systematically overestimated by misuse of the parameters bulk density and stone content

2016 ◽  
Author(s):  
Christopher Poeplau ◽  
Cora Vos ◽  
Axel Don
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Bulk Density ◽  
Agricultural Soils ◽  
Soil Layer ◽  
Future Studies ◽  
Soil Organic Carbon Stocks ◽  
Soc Stock ◽  
The Mean ◽  
Soc Stocks

Abstract. Estimation of soil organic carbon (SOC) stocks requires estimates of the carbon content, bulk density, stone content and depth of a respective soil layer. However, different application of these parameters could introduce a considerable bias. Here, we explain why three out of four frequently applied methods overestimate SOC stocks. In stone rich soils (> 30 Vol. %), SOC stocks could be overestimated by more than 100 %, as revealed by using German Agricultural Soil Inventory data. Due to relatively low stone content, the mean systematic overestimation for German agricultural soils was 2.1–10.1 % for three different commonly used equations. The equation ensemble as re-formulated here might help to unify SOC stock determination and avoid overestimation in future studies.

The resilience of soil organic carbon stocks under contrasting hill country pasture management practices

2021 ◽  
Vol 17 ◽  
Author(s):  
Alec Mackay ◽  
Ronaldo Eduardo Vibart ◽  
Catherine McKenzie ◽  
Brian Devantier ◽  
Emma Noakes
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Management Practices ◽  
Pasture Management ◽  
Single Superphosphate ◽  
Hill Country ◽  
Soil Organic Carbon Stocks ◽  
Environmental Goals ◽  
The Stability ◽  
Soc Stocks

In 2020 we measured the stability of soil organic carbon (SOC) concentrations and stocks under contrasting hill country pasture regimes, by sampling three slope classes and three aspect locations on each of three farmlets of a long-term phosphorus fertiliser and sheep grazing experiment. The farmlets included no annual phosphorus (NF), 125 kg of single superphosphate/ha (LF), or 375 kg superphosphate/ha (HF) that has been applied on an annual basis since 1980. Results from the 2020 sampling event were added to previous results reported from soil samples collected in 2003 and 2014. The SOC concentrations in the topsoil (0-75 mm depth), ranging from 4.23 to 5.99% across all slopes and aspects of the farmlets, fell within the normal range (≥3.5 and <7.0%) required for sustaining production and environmental goals. A trend was shown for greater SOC stocks in the topsoil in the HF farmlet (34.0 Mg/ ha) compared with the other two farmlets (31.6 Mg/ha), but this trend was not evident in the deeper soil layers (75-150, 150-300, 0-300 mm). Under the current conditions, topographical features such as slope and aspect had a more profound influence on SOC stocks than management history.

scholarly journals Soil organic carbon stock variation with climate and land use in shale derived soils

2018 ◽  
Vol 83 (6) ◽  
pp. 785-793 ◽  
Author(s):  
Ayaz Mehmood ◽  
Mohammad Akhtar ◽  
Shah Rukh ◽  
Muhammad Imran ◽  
Asma Hassan ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Atmospheric Carbon Dioxide ◽  
Anthropogenic Activities ◽  
Coniferous Forest ◽  
Soil Profiles ◽  
Soil Series ◽  
Humid Climate ◽  
Semiarid Climate ◽  
Soc Stocks

Anthropogenic activities, urbanization and industrialization cause an increase in the atmospheric carbon dioxide. Current focus of the soil scientists and the environmentalists is to quantify the carbon stocks and its flow in the agroecological system which is one of the main causes of global warming and climate change. The information on the distribution of soil organic carbon (SOC) stocks in the soil profiles in relation with changing climate is barely sufficient. Objective of this study was to quantify the effect of climate and land on the equilibrium of SOC stocks in soil profiles with development. Murree soil series (Typic Hapludolls) in humid climate and under coniferous forest, and Tirnul soil series (Typic Haplustepts) in semiarid climate under cultivation, were selected. Triplicate soil profiles were selected for each of the soils and sampled at genetic horizons level. Cumulative SOC stocks in Typic Hapludolls soil profiles (95 Mg ha-1) were significantly greater than Typic Haplustepts (30 Mg ha-1). The Typic Hapludolls had significantly greater SOC stock at each horizon level under humid climate. This research concludes that soils under forest and humid climate had higher SOC stocks as compared to the soils under semiarid climate and cultivation.

scholarly journals Soil properties override climate controls on global soil organic carbon stocks

2020 ◽  
Author(s):  
Zhongkui Luo ◽  
Raphael Viscarra-Rossel
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Properties ◽  
Physiochemical Properties ◽  
Soil Organic Carbon Stocks ◽  
Global Soil ◽  
Climate Controls ◽  
Edaphic Properties ◽  
Soc Stocks

Abstract. Soil organic carbon (SOC) accounts for two-thirds of terrestrial carbon. Yet, the role of soil physiochemical properties in regulating SOC stocks is unclear, inhibiting reliable SOC predictions under land use and climatic changes. Using legacy observations from 141,584 soil profiles worldwide, we disentangle the effects of biotic, climatic and edaphic factors (a total of 30 variables) on the global spatial distribution of SOC stocks in four sequential soil layers down to 2 m. The results indicate that the 30 variables can explain 70–80 % of the global variance of SOC in the four layers, to which edaphic properties contribute ~ 60 %. Soil lower limit is the most important individual soil properties, positively associated with SOC in all layers, while climatic variables are secondary. This dominant effect of soil properties challenges current climate-driven framework of SOC dynamics, and need to be considered to reliably project SOC changes for effective carbon management and climate change mitigation.

scholarly journals Soil organic carbon storage in a mountain permafrost area of Central Asia (High Altai, Russia)

AMBIO ◽  
2020 ◽  
Author(s):  
Didac Pascual ◽  
Peter Kuhry ◽  
Tatiana Raudina
Keyword(s):  
Global Warming ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Plant Cover ◽  
Permafrost Region ◽  
Total Size ◽  
Mountain Permafrost ◽  
Organic Carbon Storage ◽  
Subsequent Decomposition ◽  
Soc Stocks

AbstractThe thawing and subsequent decomposition of large stocks of soil organic carbon (SOC) currently stored in the northern circumpolar permafrost region are projected to result in a ‘positive’ feedback on global warming. The magnitude of this feedback can only be assessed with improved knowledge about the total size and geographic distribution of the permafrost SOC pool. This study investigates SOC storage in an under-sampled mountain permafrost area in the Russian High Altai. SOC stocks from 39 soil pits are upscaled using a GIS-based land cover classification. We found that the top 100 cm of soils in Aktru Valley and the adjacent Kuray Basin only holds on average 2.6 ± 0.6 kg C m−2 (95% confidence interval), of which only c. 1% is stored in permafrost. Global warming will result in an upward shift of alpine life zones, with new plant cover and soil development at higher elevations. As a result, this type of mountain permafrost area might act as a net C sink in the future, representing a ‘negative’ feedback on global warming.

scholarly journals Soil organic carbon stocks are systematically overestimated by misuse of the parameters bulk density and rock fragment content

SOIL ◽  
2017 ◽  
Vol 3 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Christopher Poeplau ◽  
Cora Vos ◽  
Axel Don
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Bulk Density ◽  
Agricultural Soils ◽  
Soil Layer ◽  
Rock Fragment ◽  
Rock Fragments ◽  
Soil Organic Carbon Stocks ◽  
Soc Stocks ◽  
Rock Fragment Content

Abstract. Estimation of soil organic carbon (SOC) stocks requires estimates of the carbon content, bulk density, rock fragment content and depth of a respective soil layer. However, different application of these parameters could introduce a considerable bias. Here, we explain why three out of four frequently applied methods overestimate SOC stocks. In soils rich in rock fragments (> 30 vol. %), SOC stocks could be overestimated by more than 100 %, as revealed by using German Agricultural Soil Inventory data. Due to relatively low rock fragments content, the mean systematic overestimation for German agricultural soils was 2.1–10.1 % for three different commonly used equations. The equation ensemble as re-formulated here might help to unify SOC stock determination and avoid overestimation in future studies.

Multi-level statistical soil profiles for assessing regional soil organic carbon stocks

Geoderma ◽  
2015 ◽  
Vol 253-254 ◽  
pp. 12-20 ◽  
Author(s):  
Sam Ottoy ◽  
Veronique Beckers ◽  
Paul Jacxsens ◽  
Martin Hermy ◽  
Jos Van Orshoven
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Stocks ◽  
Soil Profiles ◽  
Soil Organic Carbon Stocks ◽  
Multi Level
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