Spatial patterns of soil organic carbon on hillslopes: Integrating geomorphic processes and the biological C cycle

Geoderma ◽  
2006 ◽  
Vol 130 (1-2) ◽  
pp. 47-65 ◽  
Author(s):  
Kyungsoo Yoo ◽  
Ronald Amundson ◽  
Arjun M. Heimsath ◽  
William E. Dietrich
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Spatial Patterns ◽  
C Cycle ◽  
Geomorphic Processes

scholarly journals Soil organic carbon stabilization mechanisms and temperature sensitivity in old terraced soils

2021 ◽  
Vol 18 (23) ◽  
pp. 6301-6312
Author(s):  
Pengzhi Zhao ◽  
Daniel Joseph Fallu ◽  
Sara Cucchiaro ◽  
Paolo Tarolli ◽  
Clive Waddington ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Temperature Sensitivity ◽  
Land Surface ◽  
C:N Ratio ◽  
Temperature Sensitive ◽  
Organic C ◽  
Fraction Composition ◽  
Soil Burial ◽  
C Cycle

Abstract. Being the most common human-created landforms, terrace construction has resulted in an extensive perturbation of the land surface. However, our mechanistic understanding of soil organic carbon (SOC) (de-)stabilization mechanisms and the persistence of SOC stored in terraced soils is far from complete. Here we explored the factors controlling SOC stability and the temperature sensitivity (Q10) of abandoned prehistoric agricultural terrace soils in NE England using soil fractionation and temperature-sensitive incubation combined with terrace soil burial-age measurements. Results showed that although buried terrace soils contained 1.7 times more unprotected SOC (i.e., coarse particulate organic carbon) than non-terraced soils at comparable soil depths, a significantly lower potential soil respiration was observed relative to a control (non-terraced) profile. This suggests that the burial of former topsoil due to terracing provided a mechanism for stabilizing SOC. Furthermore, we observed a shift in SOC fraction composition from particulate organic C towards mineral-protected C with increasing burial age. This clear shift to more processed recalcitrant SOC with soil burial age also contributes to SOC stability in terraced soils. Temperature sensitivity incubations revealed that the dominant controls on Q10 depend on the terrace soil burial age. At relatively younger ages of soil burial, the reduction in substrate availability due to SOC mineral protection with aging attenuates the intrinsic Q10 of SOC decomposition. However, as terrace soil becomes older, SOC stocks in deep buried horizons are characterized by a higher temperature sensitivity, potentially resulting from the poor SOC quality (i.e., soil C:N ratio). In conclusion, terracing in our study site has stabilized SOC as a result of soil burial during terrace construction. The depth–age patterns of Q10 and SOC fraction composition of terraced soils observed in our study site differ from those seen in non-terraced soils, and this has implications when assessing the effects of climate warming and terrace abandonment on the terrestrial C cycle.

A comparison of soil organic carbon concentration maps of Great Britain

2021 ◽  
Author(s):  
Christopher Feeney ◽  
Jack Cosby ◽  
David Robinson ◽  
Amy Thomas ◽  
Bridget Emmett
Keyword(s):  
Machine Learning ◽  
Great Britain ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Spatial Patterns ◽  
Learning Approaches ◽  
Human Disturbances ◽  
Organic Carbon Concentration ◽  
Scale Properties ◽  
Meta Analyses

<p>Soil organic carbon (SOC) is the largest reservoir of organic carbon in the terrestrial biosphere and is the main constituent of soil organic matter, which underpins key soil functions such as storage and filtration of water, and nutrient cycling. SOC concentrations are controlled by several dynamic variables, ranging from micro-scale properties like particle aggregation, to larger-scale drivers such as climate and land cover. Hence, soils are vulnerable to climate change and human disturbances, with implications for ecosystem services such as agriculture and global warming mitigation. Recent decades have seen greater efforts to monitor SOC dynamics, such as the UKCEH Countryside Survey, and to predict concentrations of SOC where we have no measurements, using geostatistics or machine learning approaches. Yet, there is still much to be understood about what controls spatial patterns of SOC, and how effectively different modelling approaches can capture this. Here, we compare predictions by nine maps of the spatial distribution of topsoil SOC in Great Britain. We found broad similarities in SOC concentrations predicted by all maps, which each showed right-skewed distributions with similar median values (43 to 97 g kg<sup>-1</sup>). The greatest differences between maps occur at higher latitudes and are reflected in the upper ends of the SOC distributions. While the maps generally exhibit a sharp rise in SOC concentrations with increasing latitude from ~54<sup>o</sup>N, values predicted by the ISRIC-2017 and FAO-GSOC maps show weaker increases with increasing latitude, and peak at lower values of 332 g kg<sup>-1</sup> and 354 g kg<sup>-1</sup>, respectively. We demonstrate that most of the maps, regardless of the modelling approach taken or the underlying data used, produced similar estimates of SOC concentration, including broad spatial patterns. This work will form the basis of more detailed future assessments of the sensitivity of SOC mapping to analytical methods versus the data used to drive these methods, and will be used to assess the importance of using stratified random field survey approaches for generating more accurate predictions of areas that cannot be sampled. Exploration of why and where different and coincident SOC predictions occur between maps should shed light on the utility of different modelling techniques and machine-learning meta-analyses of driving variables currently used to map SOC. Understanding how SOC predictions differ across all current national scale GB maps is a first step in improving modelling and assessment of SOC stock and change.</p>

scholarly journals Soil organic carbon along an altitudinal gradient in the Despeñaperros nature reserve, Southern Spain

2014 ◽  
Vol 6 (2) ◽  
pp. 2495-2521
Author(s):  
L. Parras-Alcántara ◽  
B. Lozano-García ◽  
A. Galán-Espejo
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Altitudinal Gradient ◽  
Nature Reserve ◽  
Regional Scale ◽  
C Sequestration ◽  
Organic Carbon Content ◽  
Soil System ◽  
Disturbed Soil ◽  
C Cycle

Abstract. Soil organic carbon (SOC) is extremely important in the global carbon (C) cycle as C sequestration in non-disturbed soil ecosystems can be a sink of C and mitigate greenhouse gas driven climate change. Soil organic carbon changes in space and time are relevant to understand the soil system and its role in the C cycle, and this is why the influence of topographic position on SOC should be studied. Seven topographic positions (toposequence) were analyzed along an altitudinal gradient between 607 and 1168 m.a.s.l. in the Despeñaperros nature reserve (Natural Park). At each study site, soil control sections (25 cm intervals) were sampled. The studied soils are mineral soils with > 3% organic carbon content. The main characteristic of the studied soils is SOC reduction with depth; these results were related to the gravel content and to the bulk density. The SOC on the surface was highly variable along the altitudinal gradient ranging between 27.3 and 39.9 g kg−1. The SOC stock (SOCS) in the studied area was influenced by the altitude, varying between 53.8 and 158.0 Mg ha−1. Therefore, the altitude factor must be considered in the SOCS estimation at local-regional scale.

Small-scale spatial patterns of soil organic carbon and nitrogen stocks in permafrost-affected soils of northern Siberia

Geoderma ◽  
2018 ◽  
Vol 329 ◽  
pp. 91-107 ◽  
Author(s):  
Alevtina Evgrafova ◽  
Tilman René de la Haye ◽  
Ina Haase ◽  
Olga Shibistova ◽  
Georg Guggenberger ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Spatial Patterns ◽  
Small Scale ◽  
Northern Siberia ◽  
Carbon And Nitrogen ◽  
Carbon And Nitrogen Stocks

How much soil organic carbon sequestration is due to conservation agriculture reducing soil erosion?

Soil Research ◽  
2014 ◽  
Vol 52 (7) ◽  
pp. 717 ◽  
Author(s):  
Yong Li ◽  
Hanqing Yu ◽  
Adrian Chappell ◽  
Na Zhou ◽  
Roger Funk
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Wind Erosion ◽  
Natural Radionuclide ◽  
Conservation Agriculture ◽  
C Cycle ◽  
Land Use And Management ◽  
Dust Accumulation

Soil organic carbon (SOC) redistribution by soil erosion is fundamental to the C cycle and is a key component of global soil C accounting. Widespread conversion of cropland to forest and grassland and the adoption of conservation agriculture (minimum-till and no-till practices) worldwide and particularly in China since 2000, may have reduced wind erosion and increased SOC storage and ‘avoided’ CO2 emission. However, few SOC sequestration studies have separated changes in SOC stock caused by changes in land-use and management activity from net SOC redistribution due to reduced SOC erosion and SOC dust accumulation, particularly from individual or short-term (months) wind erosion events. We used measurements of SOC and the short-lived natural radionuclide beryllium-7 (7Be, half-life 53.3 days) to estimate net SOC redistribution for changes in several land-use and management practices in Fengning County in North China. Compared with conventional tillage (CT), conservation grassland (CG) and minimum tillage (CL) showed enhanced SOC stocks (0–245 mm depth) of ~0.8 ± 0.03 and 2.0 ± 0.06 t C ha–1 year–1 as a consequence of their land-use conversion for 5 and 3 years, respectively. However, SOC erosion on CG (0.46 ± 0.04 t C ha–1 year–1) and CL (0.52 ± 0.04 t C ha–1 year–1) plots was 54% and 47%, respectively, less than on CT (0.99 ± 0.11 t C ha–1 year–1). Net C sequestration (0–245 mm), considering SOC redistribution for CG (0.27 ± 0.12 t C ha–1 year–1; 5 years) and CL (1.53 ± 0.13 t C ha–1 year–1; 3 years), revealed an overestimate of 196% and 31% without considering SOC redistribution (CG, 0.8 ± 0.03 t C ha–1 year–1; CL, 2.0 ± 0.06 t C ha–1 year–1), respectively, relative to CT. Reduced SOC erosion and/or SOC dust accumulation by vegetation–crop cover must be included when considering SOC sequestration induced by changes in land use and management.

scholarly journals Estimating Soil Organic Carbon Stocks and Spatial Patterns with Statistical and GIS-Based Methods

PLoS ONE ◽  
2014 ◽  
Vol 9 (5) ◽  
pp. e97757 ◽  
Author(s):  
Junjun Zhi ◽  
Changwei Jing ◽  
Shengpan Lin ◽  
Cao Zhang ◽  
Qiankun Liu ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Spatial Patterns ◽  
Carbon Stocks ◽  
Soil Organic Carbon Stocks

scholarly journals Detecting small-scale spatial heterogeneity and temporal dynamics of soil organic carbon (SOC) stocks: a comparison between automatic chamber-derived C budgets and repeated soil inventories

2017 ◽  
Vol 14 (4) ◽  
pp. 1003-1019 ◽  
Author(s):  
Mathias Hoffmann ◽  
Nicole Jurisch ◽  
Juana Garcia Alba ◽  
Elisa Albiac Borraz ◽  
Marten Schmidt ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Spatial Heterogeneity ◽  
Temporal Dynamics ◽  
Small Scale ◽  
Short Term ◽  
C Cycle ◽  
Spatial Differences ◽  
Northeastern Germany ◽  
Soc Stocks

Abstract. Carbon (C) sequestration in soils plays a key role in the global C cycle. It is therefore crucial to adequately monitor dynamics in soil organic carbon (ΔSOC) stocks when aiming to reveal underlying processes and potential drivers. However, small-scale spatial (10–30 m) and temporal changes in SOC stocks, particularly pronounced in arable lands, are hard to assess. The main reasons for this are limitations of the well-established methods. On the one hand, repeated soil inventories, often used in long-term field trials, reveal spatial patterns and trends in ΔSOC but require a longer observation period and a sufficient number of repetitions. On the other hand, eddy covariance measurements of C fluxes towards a complete C budget of the soil–plant–atmosphere system may help to obtain temporal ΔSOC patterns but lack small-scale spatial resolution. To overcome these limitations, this study presents a reliable method to detect both short-term temporal dynamics as well as small-scale spatial differences of ΔSOC using measurements of the net ecosystem carbon balance (NECB) as a proxy. To estimate the NECB, a combination of automatic chamber (AC) measurements of CO2 exchange and empirically modeled aboveground biomass development (NPPshoot) were used. To verify our method, results were compared with ΔSOC observed by soil resampling. Soil resampling and AC measurements were performed from 2010 to 2014 at a colluvial depression located in the hummocky ground moraine landscape of northeastern Germany. The measurement site is characterized by a variable groundwater level (GWL) and pronounced small-scale spatial heterogeneity regarding SOC and nitrogen (Nt) stocks. Tendencies and magnitude of ΔSOC values derived by AC measurements and repeated soil inventories corresponded well. The period of maximum plant growth was identified as being most important for the development of spatial differences in annual ΔSOC. Hence, we were able to confirm that AC-based C budgets are able to reveal small-scale spatial differences and short-term temporal dynamics of ΔSOC.

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