Consistent mineral-associated organic carbon chemistry with variable erosion rates in a mountainous landscape

Abstract In arid and semiarid ecosystems, plant interspaces are frequently covered by communities of cyanobacteria, algae, lichens and mosses, known as biocrusts. These crusts often act as runoff sources and are involved in soil stabilization and fertility, as they prevent erosion by water and wind, fix atmospheric C and N and contribute large amounts of C to soil. Their contribution to the C balance as photosynthetically active surfaces in arid and semiarid regions is receiving growing attention. However, very few studies have explicitly evaluated their contribution to organic carbon (OC) lost from runoff and erosion, which is necessary to ascertain the role of biocrusts in the ecosystem C balance. Furthermore, biocrusts are not resilient to physical disturbances, which generally cause the loss of the biocrust and thus, an increase in runoff and erosion, dust emissions, and sediment and nutrient losses. The aim of this study was to find out the influence of biocrusts and their removal on dissolved and sediment organic carbon losses. One-hour extreme rainfall simulations (50 mm h-1) were performed on small plots set up on physical soil crusts and three types of biocrusts, representing a development gradient, and also on plots where these crusts were removed from. Runoff and erosion rates, dissolved organic carbon (DOC) and organic carbon bonded to sediments (SdOC) were measured during the simulated rain. Our results showed different SdOC and DOC for the different biocrusts and also that the presence of biocrusts substantially decreased total organic carbon (TOC) (average 1.80±1.86 g m-2) compared to physical soil crusts (7.83±3.27 g m-2). Within biocrusts, TOC losses decreased as biocrusts developed, and erosion rates were lower. Thus, erosion drove TOC losses while no significant direct relationships were found between TOC losses and runoff. In both physical crusts and biocrusts, DOC and SdOC concentrations were higher during the first minutes after runoff began and decreased over time as nutrient-enriched fine particles were washed away by runoff water. Crust removal caused a strong increase in water erosion and TOC losses. The strongest impacts on TOC losses after crust removal occurred on the lichen plots, due to the increased erosion when they were removed. DOC concentration was higher in biocrust-removed soils than in intact biocrusts, probably because OC is more strongly retained by BSC structures, but easily blown away in soils devoid of them. However, SdOC concentration was higher in intact than removed biocrusts associated with greater OC content in the top crust than in the soil once the crust is scraped off. Consequently, the loss of biocrusts leads to OC impoverishment of nutrient-limited interplant spaces in arid and semiarid areas and the reduction of soil OC heterogeneity, essential for vegetation productivity and functioning of this type of ecosystems.

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The effect of landuse on soil organic carbon chemistry and sorption of pesticides and metabolites

Chemosphere ◽

10.1016/j.chemosphere.2005.01.027 ◽

2005 ◽

Vol 60 (4) ◽

pp. 531-541 ◽

Cited By ~ 12

Author(s):

D.P. Oliver ◽

J.A. Baldock ◽

R.S. Kookana ◽

S. Grocke

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Carbon Chemistry

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Future climate variability impacts on potential erosion and soil organic carbon in European croplands

Biogeosciences Discussions ◽

10.5194/bgd-11-1561-2014 ◽

2014 ◽

Vol 11 (1) ◽

pp. 1561-1585 ◽

Cited By ~ 2

Author(s):

M. van der Velde ◽

J. Balkovič ◽

C. Beer ◽

N. Khabarov ◽

M. Kuhnert ◽

...

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Climate Variability ◽

Future Climate ◽

Climate Data ◽

Climate Trend ◽

Erosion Rates ◽

Soc Stock ◽

The Impact ◽

Earth System Models

Abstract. We investigate the impact of future climate variability on the potential vulnerability of soils to erosion and the consequences for soil organic carbon (SOC) in European croplands. Soil erosion is an important carbon flux not characterized in Earth System Models. We use a~European implementation of EPIC, driven by reference climate data (CNTRL), and climate data with reduced variability (REDVAR). Whether erosion regimes will change across European cropland depends on the spatial conjunction of expected changes in climate variability and physiographic conditions conducive to erosion. We isolated the effect of erosion by performing simulations with and without erosion. Median CNTRL and REDVAR erosion rates equalled 14.4 and 9.1 ton ha−1, and 19.1 and 9.7, for 1981–2010 and 2071–2100, respectively. The total amount of carbon lost from European cropland due to erosion was estimated at 769 Tg C for 1981–2010 (from a total storage of 6197 Tg C without erosion) under CNTRL climate. Climate trend impacts reduce the European cropland SOC stock by 578 Tg C without – and by 683 Tg C with erosion, from 1981 to 2100. Climate variability compounds these impacts and decreases the stock by an estimated 170 Tg without erosion and by 314 Tg C with erosion, by the end of the century. Future climate variability and erosion will thus compound impacts on SOC stocks arising from gradual climate change alone.

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Estimating soil organic carbon redistribution in three major river basins of China based on erosion processes

Soil Research ◽

10.1071/sr19325 ◽

2020 ◽

Vol 58 (6) ◽

pp. 540

Author(s):

Yan Yang ◽

Qiuan Zhu ◽

Jinxun Liu ◽

Mingxu Li ◽

Minshu Yuan ◽

...

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Yangtze River ◽

Yellow River ◽

River Basins ◽

Water Erosion ◽

Pearl River ◽

The Yangtze River ◽

Erosion Rates ◽

Erosion Processes

Soil erosion by water affects soil organic carbon (SOC) migration and distribution, which are important processes for defining ecosystem carbon sources and sinks. Little has been done to quantify soil carbon erosion in the three major basins in China, the Yangtze River, Yellow River and Pearl River Basins, which contain the most eroded areas. This research attempts to quantify the lateral movement of SOC based on spatial and temporal patterns of water erosion rates derived from an empirical Unit Stream Power Erosion Deposition Model (USPED) model. The water erosion rates simulated by the USPED model agreed reasonably with observations (R2 = 0.43, P < 0.01). We showed that regional water erosion ranged within 23.3–50 Mg ha–1 year–1 during 1992–2013, inducing the lateral redistribution of SOC caused by erosion in the range of 0.027–0.049 Mg C ha–1 year–1, and that caused by deposition of 0.0079–0.015 Mg C ha–1 year–1, in the three basins. The total eroded SOC was 0.006, 0.002 and 0.001 Pg year–1 in the Yangtze River, Yellow River and Pearl River Basins respectively. The net eroded SOC in the three basins was ~0.0075 Pg C year–1. Overall, the annual average redistributed SOC rate caused by erosion was greater than that caused by deposition, and the SOC loss in the Yangtze River Basin was greatest among the three basins. Our study suggests that considering both processes of erosion and deposition – as well as effects of topography, rainfall, land use types and their interactions – on these processes are important to understand SOC redistribution caused by water erosion.

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An auspicious landscape: Quantifying transient glacial incision in the Patagonian Andes from ~6 Ma to present

10.5194/egusphere-egu21-3278 ◽

2021 ◽

Author(s):

Chelsea Willett ◽

Keith Ma ◽

Mark Brandon ◽

Jeremy Hourigan ◽

Elizabeth Christeleit ◽

...

Keyword(s):

Source Region ◽

Fold Increase ◽

Erosion Rates ◽

Local Erosion ◽

Characteristic Features ◽

Mountainous Landscape ◽

Uplift And Erosion ◽

Patagonian Andes ◽

Natural Laboratory

The topography, climate, and geology of the central Patagonian Andes provide an auspicious natural laboratory to track long-term rates of erosion in a dynamic mountainous landscape. Herein, we report a mountain-scale record of erosion rates in the central Patagonian Andes from >10 million years (Ma) ago to present, which covers the transition from a fluvial to alpine glaciated landscape. Apatite (U-Th)/He ages of 72 granitic cobbles from alpine glacial deposits show slow erosion before ~6 Ma ago, followed by a two- to three-fold increase in the spatially averaged erosion rate of the source region after the onset of alpine glaciations and a 15-fold increase in the top 25% of the distribution. This transition is followed by a pronounced decrease in erosion rates over the past ~3 Ma. We ascribe the pulse of fast erosion to local deepening and widening of valleys, which are characteristic features of alpine glaciated landscapes. The subsequent decline in local erosion rates may represent a return toward a balance between rock uplift and erosion.

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SOIL REDISTRIBUTION ON THREE CULTIVATED NEW BRUNSWICK HILLSLOPES CALCULATED FROM 137Cs MEASUREMENTS, SOLUM DATA AND THE USLE

Canadian Journal of Soil Science ◽

10.4141/cjss86-071 ◽

1986 ◽

Vol 66 (4) ◽

pp. 721-730 ◽

Cited By ~ 55

Author(s):

E. DE JONG ◽

C. WANG ◽

H. W. REES

Keyword(s):

Organic Carbon ◽

New Brunswick ◽

Carbon Content ◽

Soil Profile ◽

Organic Carbon Content ◽

Erosion Rates ◽

The Past ◽

Severe Erosion ◽

Nearly Continuous ◽

Soil Losses

137Cs, solum data and the USLE were used to estimate soil erosion on three medium-textured soils in New Brunswick that had been in nearly continuous potato monoculture over the past 15 yr. Sampling transects were located on slopes ranging from 425 to 1040 m long, and from 4.8 to 6.0% slope. Ten equally spaced sites were sampled on each transect. The 137Cs data were used to divide the sampling sites into four groups: deposition, little erosion or deposition, moderately eroded and severely eroded areas. The four groups generally agreed well with soil profile properties. Solum, A horizon thickness and organic carbon content of the A horizon all decreased going from depositional sites to sites with severe erosion. Variations in A horizon thickness and organic carbon content explained about 65% of the variation in 137Cs. Soil losses predicted by the USLE were better correlated with soil losses calculated from 137Cs when the 137Cs data were used to delineate slope segments that were subject to erosion than when 137Cs and USLE soil losses were calculated on a field basis. The USLE overestimated soil losses at high erosion rates. Key words: Erosion, deposition, 137Cs, USLE, soil profile

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Organic Carbon Chemistry in Soils Observed by Synchrotron-Based Spectroscopy

Synchrotron-Based Techniques in Soils and Sediments - Developments in Soil Science ◽

10.1016/s0166-2481(10)34010-4 ◽

2010 ◽

pp. 289-312 ◽

Cited By ~ 20

Author(s):

Johannes Lehmann ◽

Dawit Solomon

Keyword(s):

Organic Carbon ◽

Carbon Chemistry

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Global soil organic carbon removal by water erosion under climate change and land use change during AD 1850–2005

Biogeosciences ◽

10.5194/bg-15-4459-2018 ◽

2018 ◽

Vol 15 (14) ◽

pp. 4459-4480 ◽

Cited By ~ 17

Author(s):

Victoria Naipal ◽

Philippe Ciais ◽

Yilong Wang ◽

Ronny Lauerwald ◽

Bertrand Guenet ◽

...

Keyword(s):

Land Use ◽

Soil Erosion ◽

Organic Carbon ◽

Land Use Change ◽

Soil Organic Carbon ◽

Climate Variability ◽

Carbon Cycle ◽

Land Surface ◽

Erosion Rates ◽

Soil Erosion Rates

Abstract. Erosion is an Earth system process that transports carbon laterally across the land surface and is currently accelerated by anthropogenic activities. Anthropogenic land cover change has accelerated soil erosion rates by rainfall and runoff substantially, mobilizing vast quantities of soil organic carbon (SOC) globally. At timescales of decennia to millennia this mobilized SOC can significantly alter previously estimated carbon emissions from land use change (LUC). However, a full understanding of the impact of erosion on land–atmosphere carbon exchange is still missing. The aim of this study is to better constrain the terrestrial carbon fluxes by developing methods compatible with land surface models (LSMs) in order to explicitly represent the links between soil erosion by rainfall and runoff and carbon dynamics. For this we use an emulator that represents the carbon cycle of a LSM, in combination with the Revised Universal Soil Loss Equation (RUSLE) model. We applied this modeling framework at the global scale to evaluate the effects of potential soil erosion (soil removal only) in the presence of other perturbations of the carbon cycle: elevated atmospheric CO2, climate variability, and LUC. We find that over the period AD 1850–2005 acceleration of soil erosion leads to a total potential SOC removal flux of 74±18 Pg C, of which 79 %–85 % occurs on agricultural land and grassland. Using our best estimates for soil erosion we find that including soil erosion in the SOC-dynamics scheme results in an increase of 62 % of the cumulative loss of SOC over 1850–2005 due to the combined effects of climate variability, increasing atmospheric CO2 and LUC. This additional erosional loss decreases the cumulative global carbon sink on land by 2 Pg of carbon for this specific period, with the largest effects found for the tropics, where deforestation and agricultural expansion increased soil erosion rates significantly. We conclude that the potential effect of soil erosion on the global SOC stock is comparable to the effects of climate or LUC. It is thus necessary to include soil erosion in assessments of LUC and evaluations of the terrestrial carbon cycle.

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Dissolved organic carbon chemistry and dynamics in contrasting forest and grassland soils

Biogeochemistry ◽

10.1007/s10533-008-9211-x ◽

2008 ◽

Vol 89 (2) ◽

pp. 181-198 ◽

Cited By ~ 134

Author(s):

Jonathan Sanderman ◽

Jeffrey A. Baldock ◽

Ronald Amundson

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Grassland Soils ◽

Carbon Chemistry

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Soil erosion leads to significant mobilisation of terrestrial organic and inorganic carbon

10.5194/egusphere-egu2020-11546 ◽

2020 ◽

Author(s):

Laura Turnbull ◽

John Wainwright

Keyword(s):

Land Use ◽

Soil Erosion ◽

Organic Carbon ◽

Soil Degradation ◽

Inorganic Carbon ◽

Dust Emission ◽

Water Erosion ◽

Land Use Systems ◽

Erosion Rates ◽

Soil Erosion Rates

Soil carbon content is greatly affected by soil degradation &#8211; in particular erosional processes &#8211; which cannot be ignored in the context of the global C cycle. Soil degradation, driven largely by wind and water erosion, affects up to 66% of Earth&#8217;s terrestrial surface. Understanding how soil degradation affects soil organic carbon (SOC) and soil inorganic carbon (SIC) stocks is an essential component of understanding global C cycling and global C budgets, and is essential for improved C management and climate-change mitigation policies.In this study, we quantify the distribution of SOC and SIC, and estimate their combined effects on carbon mobilisation via water and wind-driven erosion. We estimate spatially variable water-driven erosion rates for different land-use systems and degradation severities using values obtained from a meta-analysis of soil erosion rates, and undertake stochastic simulations to account for possible uncertainty in our estimates. For wind-driven soil erosion rates we use modelled dust emission rates from AeroCom Phase III model experiments for the 2010 control year, for 14 different models. We use the Harmonized World Soil Database v1.2 to calculate SOC and SIC stocks, the GLASOD map of soil degradation to estimate soil degradation severities and the Land Use Systems of the World database to estimate water-driven erosion rates associated with different land-use systems. &#160;We find that 651 Pg SOC and 306 Pg SIC (in the top 1-m of soil) is located in degrading soils. We estimate global water-driven soil erosion to be 216.4 Pg yr-1, which results in the mobilisation of ~2.9536 Pg OC yr-1. Accounting for the enrichment of organic carbon in eroded sediment increases these estimates up to 12.2 Pg SOC yr-1. A minimum estimate of SIC mobilisation by water erosion is ~0.5592 Pg IC yr-1. Dust emission model ensemble results indicate that ~19.8 Pg soil is eroded for the 2010 AeroCom reference year, with ~11.1 Pg deposited via dry deposition and ~7.2 &#160;Pg deposited via wet deposition. The total amount of SOC and SIC mobilised by water-driven erosion is greater than wind-driven erosion, and the spatial patterns of SIC and SOC mobilisation by wind and water vary considerably. Across all land-use types, water-driven carbon mobilisation is higher than wind. Water-driven SOC mobilisation is highest in cropland (~ 2.6602 Pg OC yr-1) where high erosion rates coincide with average SOC content of 68.4 tonnes ha-1. SIC mobilisation follows the same pattern in relation to land use, with highest water-driven mobilisation in cropland (~0.4660 Pg IC yr-1) and highest wind-driven mobilisation in bare areas (0.05 Pg IC yr-1). Overall, wind-driven erosion mobilises more IC than OC.Future land-use change has great potential to affect global soil carbon stocks further, especially with increases in the severity of soil degradation as human pressures on agricultural systems increase.

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