A method to detect soil carbon degradation during soil erosion

Abstract. Soil erosion has been discussed intensively but controversial both as a significant source or a significant sink of atmospheric carbon possibly explaining the gap in the global carbon budget. One of the major points of discussion has been whether or not carbon is degraded and mineralized to CO2 during detachment, transport and deposition of soil material. By combining the caesium-137 (137Cs) approach (quantification of erosion rates) with stable carbon isotope signatures (process indicator of mixing versus degradation of carbon pools) we were able to show that degradation of carbon occurs during soil erosion processes at the investigated mountain grasslands in the central Swiss Alps (Urseren Valley, Canton Uri). Transects from upland (erosion source) to wetland soils (erosion sinks) of sites affected by sheet and land slide erosion were sampled. Analysis of 137Cs yielded an input of 2 and 2.6 t ha−1 yr−1 of soil material into the wetlands sites. Assuming no degradation of soil organic carbon during detachment and transport, carbon isotope signature of soil organic carbon in the wetlands could only be explained with an assumed 800 and 400 years of erosion input into the wetlands. The latter is highly unlikely with alpine peat growth rates indicating that the upper horizons might have an age between 7 and 200 years. While we do not conclude from our data that eroded soil organic carbon is generally degraded during detachment and transport, we propose this method to gain more information on process dynamics during soil erosion from oxic upland to anoxic wetland soils, sediments or water bodies.

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A method to detect soil carbon degradation during soil erosion

Biogeosciences ◽

10.5194/bg-6-2541-2009 ◽

2009 ◽

Vol 6 (11) ◽

pp. 2541-2547 ◽

Cited By ~ 25

Author(s):

C. Alewell ◽

M. Schaub ◽

F. Conen

Keyword(s):

Soil Erosion ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Carbon Isotope ◽

Stable Carbon Isotope ◽

Swiss Alps ◽

Wetland Soils ◽

Soil Material ◽

Process Indicator ◽

Erosion Processes

Abstract. Soil erosion has been discussed intensively but controversial both as a significant source or a significant sink of atmospheric carbon possibly explaining the gap in the global carbon budget. One of the major points of discussion has been whether or not carbon is degraded and mineralized to CO2 during detachment, transport and deposition of soil material. By combining the caesium-137 (137Cs) approach (quantification of erosion rates) with stable carbon isotope signatures (process indicator of mixing versus degradation of carbon pools) we were able to show that degradation of carbon occurs during soil erosion processes at the investigated mountain grasslands in the central Swiss Alps (Urseren Valley, Canton Uri). Transects from upland (erosion source) to wetland soils (erosion sinks) of sites affected by sheet and land slide erosion were sampled. Analysis of 137Cs yielded an input of 2 and 4.6 tha−1 yr−1 of soil material into the wetlands sites. Assuming no degradation of soil organic carbon during detachment and transport, carbon isotope signature of soil organic carbon in the wetlands could only be explained with an assumed 500–600 and 350–400 years of erosion input into the wetlands Laui and Spissen, respectively. The latter is highly unlikely with alpine peat growth rates indicating that the upper horizons might have an age between 7 and 200 years. While we do not conclude from our data that eroded soil organic carbon is generally degraded during detachment and transport, we propose this method to gain more information on process dynamics during soil erosion from oxic upland to anoxic wetland soils, sediments or water bodies.

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The stable carbon isotope composition of soil organic carbon and pedogenic carbonates along a bioclimatic gradient in the Palouse region, Washington State, USA

Geoderma ◽

10.1016/j.geoderma.2004.03.006 ◽

2005 ◽

Vol 124 (1-2) ◽

pp. 37-47 ◽

Cited By ~ 102

Author(s):

B.A. Stevenson ◽

E.F. Kelly ◽

E.V. McDonald ◽

A.J. Busacca

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Carbon Isotope ◽

Isotope Composition ◽

Stable Carbon Isotope ◽

Washington State ◽

Carbon Isotope Composition ◽

Stable Carbon ◽

Stable Carbon Isotope Composition ◽

Pedogenic Carbonates

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Stable carbon isotope depth profiles and soil organic carbon dynamics in the lower Mississippi Basin

Geoderma ◽

10.1016/j.geoderma.2005.03.005 ◽

2006 ◽

Vol 131 (1-2) ◽

pp. 89-109 ◽

Cited By ~ 119

Author(s):

Jonathan G. Wynn ◽

Jennifer W. Harden ◽

Terry L. Fries

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Carbon Isotope ◽

Stable Carbon Isotope ◽

Carbon Dynamics ◽

Stable Carbon ◽

Depth Profiles ◽

Soil Organic Carbon Dynamics

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Estimation of Slow- and Fast-Cycling Soil Organic Carbon Pools from 6N HCl Hydrolysis

Radiocarbon ◽

10.1017/s0033822200017604 ◽

1996 ◽

Vol 38 (2) ◽

pp. 231-239 ◽

Cited By ~ 112

Author(s):

S. W. Leavitt ◽

R. F. Follett ◽

E. A. Paul

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Soil Carbon ◽

Acid Hydrolysis ◽

Carbon Isotope ◽

Great Plains ◽

Stable Carbon Isotope ◽

Isotope Tracer ◽

Hydrolysis Residue ◽

Residue Fraction

Acid hydrolysis is used to fractionate the soil organic carbon pool into relatively slow- and fast-cycling compartments on soils from Arizona, the Great Plains states and Michigan collected for carbon isotope tracer studies related to soil carbon sequestration, for studies of shifts in C3/C4 vegetation, and for “pre-bomb” soil-carbon inventories. Prior to hydrolysis, soil samples are first treated with cold 0.5–1N HCl to remove soil carbonates if necessary. Samples are then dispersed in a concentrated NaCl solution (ρ≍1.2 g cm-3) and floated plant fragments are skimmed off the surface. After rinsing and drying, all remaining recognizable plant fragments are picked from the soil under 20x magnification. Plant-free soils, and hot, 6N HCl acid-hydrolysis residue and hydrolyzate fractions are analyzed for carbon content, δ13C and 14C age, and the carbon distribution is verified within 1–2% by stable-carbon isotope mass balance. On average, the recalcitrant residue fraction is 1800 yr older and 2.6% more 13C-depleted than total soil organic carbon. A test of hydrolysis with fresh plant fragments produced as much as 71–76% in the acid-hydrolysis residue pool. Thus, if plant fragments are not largely removed prior to hydrolysis, the residue fraction may date much younger than it actually is.

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Lateral transport of SOC induced by water erosion in a Spanish agroecosystem

10.5194/egusphere-egu2020-17676 ◽

2020 ◽

Author(s):

Leticia Gaspar ◽

Lionel Mabit ◽

Ivan Lizaga ◽

Ana Navas

Keyword(s):

Land Use ◽

Soil Erosion ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Management Practices ◽

Water Erosion ◽

Land Uses ◽

Lateral Movement ◽

Erosion Processes ◽

Depositional Processes

The main route for the lateral movement of soil organic carbon (SOC) is water erosion. Awareness of the distribution and magnitude of land carbon mobilization is important both for improving models of the carbon cycle and for management practices aimed to preserve carbon stocks and enhance carbon sinks. There is a need to consider the global significance of soil erosion from soil organic carbon cycling schemes and for this reason, the movement of SOC during erosion processes should be elucidated.Our study aims to estimate the SOC redistribution induced by water erosion during a 40 years period in an agroforestry mountain ecosystem located in northern Spain. To this purpose, topographically driven transects were selected with mixed land uses to i) assess what factors modify the runoff patterns with impact on soil and carbon redistribution and ii) evaluate the mobilization of topsoil organic carbon along the transects.The lateral movement of SOC shows similar spatial patterns with that of soil erosion. To identify whether erosional or depositional processes have been predominant in the sampling sites we used 137Cs inventories and the characterization of terrain attributes of the study with a detailed analysis of the main runoff pathways. Results indicate that SOC losses were related to an increase in water flow accumulation, while the highest SOC gains were recorded at concave positions. Soil erosion processes and the content of SOC in soils are the two main factors controlling carbon budgets. The topographical and geomorphological characteristics of the transects, the spatial distribution of land uses and the presence of landscape linear elements such as terraces or paths, affect runoff and determine the sediment connectivity and carbon dynamics along the slopes.The interactions between topography and land use produce significant positive or negative effects on SOC accumulation, particularly in areas with complex topography, as the results obtained in our study sustain. Even though the effect of topography and land use/land cover and their interactions on the horizontal distributions of carbon remains largely unknown, our approach contributes to better understand the pattern of gains and losses of soil organic and inorganic carbon induced by water erosion.

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Assessing biogeochemical and human-induced drivers of soil organic carbon to inform restoration activities in Rwanda

10.5194/soil-2020-67 ◽

2020 ◽

Author(s):

Leigh Ann Winowiecki ◽

Athanase Mukuralinda ◽

Aida Bargués-Tobella ◽

Providence Mujawamaria ◽

Elisée Bahati Ntawuhiganayo ◽

...

Keyword(s):

Soil Erosion ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Land Degradation ◽

Spatial Scales ◽

Stable Carbon Isotope ◽

Health Indicators ◽

Crop Productivity ◽

Land Restoration ◽

Wide Range

Abstract. Land restoration is of critical importance in Rwanda, where land degradation negatively impacts crop productivity, water, food and nutrition security. We implemented the Land Degradation Surveillance Framework in Kayonza and Nyagatare districts in eastern Rwanda to assess baseline status of key soil and land health indicators, including soil organic carbon (SOC) and soil erosion prevalence. We collected 300 topsoil (0–20 cm) and 281 subsoil (20–50 cm) samples from two 100 km2 sites. We coupled the soil health indicators with vegetation structure, tree density and tree diversity assessments. Mean topsoil organic carbon was low overall, 20.9 g kg−1 in Kayonza and 17.3 g kg−1 in Nyagatare. Stable carbon isotope values (d13CV-PDB ) ranged from −15.35 to −21.34 ‰ indicating a wide range of plant communities with both C3 and C4 photosynthetic pathways. Soil carbon content decreased with increasing sand content across both sites and at both sampling depths and was lowest in croplands compared to shrubland, woodland and grasslands. Field-saturated hydraulic conductivity (Kfs) was estimated based on infiltration measurements, with a median of 76 mm h−1 in Kayonza and 62 mm h−1 in Nyagatare, respectively. Topsoil OC had a positive effect on Kfs, whereas pH, sand and compaction had negative effects. Soil erosion was highest in plots classified as woodland and shrubland. Maps of soil erosion and SOC at 30-m resolution were produced with high accuracy and showed high variability across the region. These data and analysis demonstrate the importance of systematically monitoring multiple indicators at multiple spatial scales to assess drivers of degradation and their impact on soil organic carbon dynamics.

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Faculty Opinions recommendation of The global significance of omitting soil erosion from soil organic carbon cycling schemes.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.726758574.793523375 ◽

2016 ◽

Author(s):

Dennis Baldocchi

Keyword(s):

Soil Erosion ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Carbon Cycling ◽

Organic Carbon Cycling

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Topographic Position, Land Use and Soil Management Effects on Soil Organic Carbon (Vineyard Region of Niš, Serbia)

Agronomy ◽

10.3390/agronomy11071438 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1438

Author(s):

Snežana Jakšić ◽

Jordana Ninkov ◽

Stanko Milić ◽

Jovica Vasin ◽

Milorad Živanov ◽

...

Keyword(s):

Land Use ◽

Surface Layer ◽

Spatial Distribution ◽

Soil Erosion ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Soil Compaction ◽

Soil Management ◽

Forest Land ◽

Topographic Position

Spatial distribution of soil organic carbon (SOC) is the result of a combination of various factors related to both the natural environment and anthropogenic activities. The aim of this study was to examine (i) the state of SOC in topsoil and subsoil of vineyards compared to the nearest forest, (ii) the influence of soil management on SOC, (iii) the variation in SOC content with topographic position, (iv) the intensity of soil erosion in order to estimate the leaching of SOC from upper to lower topographic positions, and (v) the significance of SOC for the reduction of soil’s susceptibility to compaction. The study area was the vineyard region of Niš, which represents a medium-sized vineyard region in Serbia. About 32% of the total land area is affected, to some degree, by soil erosion. However, according to the mean annual soil loss rate, the total area is classified as having tolerable erosion risk. Land use was shown to be an important factor that controls SOC content. The vineyards contained less SOC than forest land. The SOC content was affected by topographic position. The interactive effect of topographic position and land use on SOC was significant. The SOC of forest land was significantly higher at the upper position than at the middle and lower positions. Spatial distribution of organic carbon in vineyards was not influenced by altitude, but occurred as a consequence of different soil management practices. The deep tillage at 60–80 cm, along with application of organic amendments, showed the potential to preserve SOC in the subsoil and prevent carbon loss from the surface layer. Penetrometric resistance values indicated optimum soil compaction in the surface layer of the soil, while low permeability was observed in deeper layers. Increases in SOC content reduce soil compaction and thus the risk of erosion and landslides. Knowledge of soil carbon distribution as a function of topographic position, land use and soil management is important for sustainable production and climate change mitigation.

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