Effect of aggregate breakdown on the unevenly enriched organic carbon process in sediments under a rain-induced overland flow

2020 ◽  
Vol 204 ◽  
pp. 104752
Author(s):  
L. Liu ◽  
Z.W. Li ◽  
Z.J. Li ◽  
E.F. Liu ◽  
X.D. Nie ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Overland Flow ◽  
Aggregate Breakdown

scholarly journals Sources and export of particle-borne organic matter during a monsoon flood in a catchment of northern Laos

2015 ◽  
Vol 12 (4) ◽  
pp. 1073-1089 ◽  
Author(s):  
E. Gourdin ◽  
S. Huon ◽  
O. Evrard ◽  
O. Ribolzi ◽  
T. Bariac ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Particulate Organic Matter ◽  
Rainy Season ◽  
Overland Flow ◽  
Specific Yield ◽  
Main Stream ◽  
Δ13c And Δ15n ◽  
Suspended Organic Matter

Abstract. The yields of the tropical rivers of Southeast Asia supply large quantities of carbon to the ocean. The origin and dynamics of particulate organic matter were studied in the Houay Xon River catchment located in northern Laos during the first erosive flood of the rainy season in May 2012. This cultivated catchment is equipped with three successive gauging stations draining areas ranging between 0.2 and 11.6 km2 on the main stem of the permanent stream, and two additional stations draining 0.6 ha hillslopes. In addition, the sequential monitoring of rainwater, overland flow and suspended organic matter compositions was conducted at the 1 m2 plot scale during a storm. The composition of particulate organic matter (total organic carbon and total nitrogen concentrations, δ13C and δ15N) was determined for suspended sediment, soil surface (top 2 cm) and soil subsurface (gullies and riverbanks) samples collected in the catchment (n = 57, 65 and 11, respectively). Hydrograph separation of event water was achieved using water electric conductivity and δ18O measurements for rainfall, overland flow and river water base flow (n = 9, 30 and 57, respectively). The composition of particulate organic matter indicates that upstream suspended sediments mainly originated from cultivated soils labelled by their C3 vegetation cover (upland rice, fallow vegetation and teak plantations). In contrast, channel banks characterized by C4 vegetation (Napier grass) supplied significant quantities of sediment to the river during the flood rising stage at the upstream station as well as in downstream river sections. The highest runoff coefficient (11.7%), sediment specific yield (433 kg ha−1), total organic carbon specific yield (8.3 kg C ha−1) and overland flow contribution (78–100%) were found downstream of reforested areas planted with teaks. Swamps located along the main stream acted as sediment filters and controlled the composition of suspended organic matter. Total organic carbon specific yields were particularly high because they occurred during the first erosive storm of the rainy season, just after the period of slash-and-burn operations in the catchment.

scholarly journals The use of a raindrop aggregate destruction device to evaluate sediment and soil organic carbon transport

2015 ◽  
Vol 70 (2) ◽  
pp. 167-174 ◽  
Author(s):  
L. Xiao ◽  
Y. Hu ◽  
P. Greenwood ◽  
N. J. Kuhn
Keyword(s):  
Soil Erosion ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Size Distribution ◽  
Agricultural Soils ◽  
Natural Sediment ◽  
Soil Fractions ◽  
Aggregate Breakdown ◽  
Erosion Models ◽  
Raindrop Impact

Abstract. Raindrop impact and subsequent aggregate breakdown can potentially change the movement behaviour of soil fractions and thus alter their transport distances when compared against non-impacted aggregates. In a given water layer, the transport distances of eroded soil fractions, and thus that of the associated substances across landscapes, such as soil organic carbon (SOC) and phosphorous, are determined by the settling velocities of the eroded soil fractions. However, using mineral size distribution to represent the settling velocities of soil fractions, as often applied in current erosion models, would ignore the potential influence of aggregation on the settling behaviour of soil fractions. The destructive effects of raindrops impacting onto aggregates are also often neglected in current soil erosion models. Therefore, the objective of this study is to develop a proxy method to effectively simulate aggregate breakdown under raindrop impact, and further identify the settling velocity of eroded sediment and the associated SOC. Two agricultural soils with different sandy and silty loam textures were subjected to rainfall using a raindrop aggregate destruction device (RADD). The aggregates sustained after raindrop impact were fractionated by a settling tube into six different classes according to their respective settling velocities. The same mass amount of bulk soil of each soil type was also dispersed and sieved into the same six classes, to form a comparison in size distribution. The SOC content was measured for each settled and dispersed class. Our results show the following: (1) for an aggregated soil, applying dispersed mineral grain size distribution, rather than its actual aggregate distribution, to soil erosion models would lead to a biased estimation on the redistribution of eroded sediment and SOC; (2) the RADD designed in this study effectively captures the effects of raindrop impact on aggregate destruction and is thus able to simulate the quasi-natural sediment spatial redistribution; (3) further RADD tests with more soils under standard rainfall combined with local rainfalls are required to optimize the method.

scholarly journals Storm Dissolved Organic Carbon Dynamics in an Artificially Drained Watershed of the US Midwest

2012 ◽  
Vol 5 ◽  
pp. ASWR.S9973 ◽  
Author(s):  
Philippe G. Vidon ◽  
Hilary A Hubbard ◽  
Pilar E. Cuadra ◽  
Matthew L. Hennessy
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Overland Flow ◽  
Agricultural Watershed ◽  
Antecedent Moisture ◽  
Tile Drains ◽  
The Us ◽  
Moisture Conditions ◽  
Subsurface Drains ◽  
Antecedent Moisture Conditions

This study investigates changes in the nature, concentrations, and fluxes of dissolved organic carbon (DOC) in tile drains (aka subsurface drains), overland flow, and stream flow for 6 spring storms in an artificially drained agricultural watershed. For moderate size storms, DOC concentrations are primarily affected by variations in antecedent moisture conditions. Generally, DOC concentrations and aromaticity increase with flow, especially for storms associated with high antecedent moisture conditions. A shift in the source of DOC to the stream and tile drains from low aromaticity DOC at baseflow, to more aromatic DOC during storms was observed. Data indicates that increases in the frequency and intensity of large precipitation events as well as wetter conditions in spring would likely lead not only to an increase in DOC fluxes (simply because of higher discharge) but also to an increase in the amount of DOC exported for every unit of flow.

Influence of catchment topography on water chemistry in southeastern Québec Shield lakes

1997 ◽  
Vol 54 (10) ◽  
pp. 2215-2227 ◽  
Author(s):  
Pierre D'Arcy ◽  
Richard Carignan
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Water Chemistry ◽  
Surface Waters ◽  
Overland Flow ◽  
Canadian Shield ◽  
Chl A ◽  
Lake Water Chemistry ◽  
High Runoff ◽  
Shield Lakes

For 30 Canadian Shield lakes of southeastern Quebec, catchment slope and lake morphometry account for 50-70% of the variability of chlorophyll a (Chl a), dissolved organic carbon (DOC), total phosphorus (TP), NO3- , and NH4+ . Dissolved organic carbon, TP, Chl a, Ca, and Mg are negatively related to catchment slope, whereas NO3- and NH4+ increase with increasing slope. Concentrations of more conservative constituents (SO42-, Na, K) increase with decreasing elevation as a result of higher evapotranspiration and lower precipitation at low elevations. Catchment variables (slope, drainage area, percent wetlands) are as good predictors of Chl a (r2 = 0.7) as are water chemistry variables (TP, Ca, Mg, and pH). Dominant vegetation (deciduous vs. coniferous) has little or no influence on lake water chemistry. Hydrogeological data for the Canadian Shield suggest that, during periods of high runoff, the development of waterlogged areas and the importance of overland flow on saturated soils are inversely proportional to catchment slope. We propose that the strong influence of catchment slope on water quality is due to slope-dependent seasonal waterlogging, which determines the fate (retention or export to surface waters) of dissolved substances produced within and moving through the forest floor.

Seasonal changes in pathways of dissolved organic carbon through a hillslope soil (Xeralf) with contrasting texture

Soil Research ◽  
1992 ◽  
Vol 30 (4) ◽  
pp. 465 ◽  
Author(s):  
DJ Chittleborough ◽  
KRJ Smettem ◽  
E Cotsaris ◽  
FW Leaney
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Overland Flow ◽  
Podzolic Soil ◽  
Marked Decrease ◽  
Soil Surface ◽  
Storm Events ◽  
Dry Period ◽  
Doc Concentration ◽  
Texture Contrast

The pathways of dissolved organic carbon (DOC) through a podzolic soil (Xeralf) with strong texture contrast are described. During winter, most of the DOC passes through macropores in the profile and flows laterally through the B horizons. During summer the presence of dry, hydrophobic organic matter on the soil surface and the A1 horizon causes DOC to flow overland. DOC concentrations vary seasonally. Highest concentrations are measured during summer overland flow. For all horizons, the longer the dry period the greater the DOC concentration in the subsequent flow. During storm events there is a marked flushing effect in the B horizons but in the A horizon and the surface, DOC concentrations tend to rise. There was a marked decrease in DOC concentration in flow from the B3 compared to the upper horizons. This may be due to adsorption by fine clays lining the macropores.

scholarly journals An integrated Dissolved Organic Carbon Dynamics Model (DOCDM 1.0): model development and a case study in the Alaskan Yukon River Basin

2015 ◽  
Vol 8 (12) ◽  
pp. 10411-10454 ◽  
Author(s):  
X. Lu ◽  
Q. Zhuang
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Overland Flow ◽  
Terrestrial Ecosystems ◽  
Carbon Dynamics ◽  
Water Infiltration ◽  
Dynamics Model ◽  
Study Region ◽  
Doc Export ◽  
Doc Production

Abstract. Quantitative understanding of the variation in dissolved organic carbon (DOC) is important to studying the terrestrial ecosystem carbon cycle. This study presents a process-based, dissolved organic carbon dynamics model (DOCDM 1.0) that couples the soil heat conduction, water flow, DOC production, mineralization and transport in both surface and subsurface of soil profile to quantify DOC dynamics in boreal terrestrial ecosystems. The model is first evaluated and then applied for a watershed in Alaska to investigate its DOC production and transport. We find that 42 and 27 % of precipitation infiltrates to soils in 2004, a warmer year, and in 1976, a colder year, respectively. Under warming conditions, DOC transported via overland flow does not show the expected decrease trend while the overland DOC yield shows a 4 % increase. The horizontal subsurface flow only accounts for 1–2 % of total water flux, but transports 30–50 % of DOC into rivers. Water flush due to water infiltration controls DOC transport. Snowmelt plays a noticeable role in DOC flush-out and DOC transport significantly depends on flowpaths in the study region. High soil temperature stimulates DOC production. The overland DOC export does not necessarily follow the DOC downward trend in surface water transport. Overall, this study shows that DOC export behavior is complex under changing temperature and hydrological conditions in cold-region watersheds. To adequately quantify DOC dynamics in northern high latitudes, more DOC and hydrological data are needed to better parameterize and test the developed model before extrapolating it to the region.

scholarly journals Sources and export of particle-borne organic matter during a monsoon flood in a catchment of northern Laos

2014 ◽  
Vol 11 (6) ◽  
pp. 9341-9378
Author(s):  
E. Gourdin ◽  
S. Huon ◽  
O. Evrard ◽  
O. Ribolzi ◽  
T. Bariac ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Particulate Organic Matter ◽  
Rainy Season ◽  
Overland Flow ◽  
Specific Yield ◽  
Δ13c And Δ15n ◽  
Teak Plantations ◽  
The Impact

Abstract. Tropical rivers of Southeast Asia are characterized by high specific carbon yields and supplies to the ocean. The origin and dynamics of particulate organic matter were studied in the Houay Xon River catchment located in northern Laos during the first erosive flood of the rainy season in May 2012. The partly cultivated catchment is equipped with three successive gauging stations draining areas ranging between 0.2 and 11.6 km2 on the main stem of the permanent stream, and two additional stations draining 0.6 ha hillslopes. In addition, the sequential monitoring of rainwater, overland flow and suspended organic matter compositions was realized at 1 m2 plot scale during a single storm. The composition of particulate organic matter (total organic carbon, total nitrogen, δ13C and δ15N) was determined for suspended sediment, soil surface and subsurface samples collected in the catchment (n = 57, 65 and 11 respectively). Hydrograph separation of event water was conducted using water electric conductivity and δ18O data measured for rainfall, overland flow and river water base flow (n = 9, 30 and 57, respectively). The composition of particulate organic matter indicates that upstream suspended sediments were mainly derived from cultivated soils labelled by their C3 vegetation cover (upland rice, fallow vegetation and teak plantations) but that collapsed riverbanks, characterized by C4 vegetation occurrence (Napier grass), significantly contributed to sediment yields during water level rise and at the downstream station. The highest runoff coefficient (11.7%), sediment specific yield (433 kg ha−1), total organic carbon specific yield (8.3 kg C ha−1) and overland flow contribution (78–100%) were found for the reforested areas covered by teak plantations. Total organic carbon specific yields were up to 2.6-fold higher (at downstream station) than the annual ones calculated 10 years earlier, before the expansion of teak plantations in the catchment. They may be attributed both to the sampling period at the onset of the rainy season (following field clearing by slash and burn) and to the impact of land use change during the past decade.

Chemical concentrations of overland flow and throughflow from pastures on sloping texture-contrast soils

2001 ◽  
Vol 52 (2) ◽  
pp. 211 ◽  
Author(s):  
J. W. Cox ◽  
A. Pitman
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Overland Flow ◽  
South Australia ◽  
Annual Rainfall ◽  
Nitrate Losses ◽  
Nitrate Concentrations ◽  
Texture Contrast ◽  
Carbon Losses ◽  
Carbon Concentrations

Shallow drains are increasingly being installed to allow cropping and improve pastures in soils prone to waterlogging. Concentrations and loads of a range of chemicals including nitrate, dissolved organic carbon, and phosphorus were measured in overland flow and throughflow (drainage) from grazed standard and improved pastures in a region of the Adelaide Hills, South Australia, with 544 mm annual rainfall. In low to average rainfall years, nitrate losses from standard pastures were up to 21 times higher in throughflow (up to 0.3 kg/ha.year) than in overland flow. Dissolved organic carbon losses from standard pastures were also highest in throughflow (up to 3.5 kg/ha.year) as were loads of Na, Cl, Al, Fe, K, and Mg. Total P loads were higher in throughflow (0.15 kg/ha.year) than in overland flow. However, P concentrations in throughflow were similar to overland flow (up to 0.5 mg/L). Chemical loads from improved pastures were higher in throughflow than in overland flow. Nitrate, dissolved organic carbon, and P losses from improved pastures were up to 0.8, 8.5, and 0.1 kg/ha.year, respectively. Improved pastures had higher dissolved organic carbon concentrations (14 mg/L) and nitrate concentrations than either the standard pastures or those reported off some dairy pastures in the region. Nitrate concentrations were highest in throughflow in subsurface tube drains below the improved pastures (up to 67 mg/L).

Pathways of phosphorus, nitrogen, and carbon movement over and through texturally differentiated soils, South Australia

Soil Research ◽  
1999 ◽  
Vol 37 (4) ◽  
pp. 679 ◽  
Author(s):  
D. J. Chittleborough ◽  
J. W. Cox ◽  
D. P. Stevens
Keyword(s):  
Organic Carbon ◽  
Overland Flow ◽  
South Australia ◽  
Catchment Management ◽  
Catchment Scale ◽  
Through Flow ◽  
Close Proximity ◽  
Significant Loading ◽  
Restrict Movement ◽  
Texture Contrast

One method for preventing the degradation of water supplies through contamination with phosphorus (P), nitrate (NO3), and dissolved organic carbon (DOC) is to restrict movement of these contaminants from the catchment into water bodies. The purpose of the study was to quantify and characterise the proportion of NO3, P, and DOC moving from duplex soils by overland flow and through-flow on a sub-catchment scale, and to characterise soil properties that influence their movement. Two sites in the Adelaide Hills (South Australia) with contrasting duplex soils were instrumented to collect overland flow and through-flow from the soils A and B horizon. Each site contained 2 sub-catchments in close proximity. Sub-catchments were well defined by the natural topography sloping from hillcrest to a stream headwater. Soil type, especially the degree of texture contrast, the macroporosity, and the proportion of clay in the B horizon, had a large influence on the pathways of water, and therefore P, DOC, and NO3 movement. Environmentally significant concentrations of P (>0�1 mg/L) and NO3-N (>0�5 mg/L) moved overland and through these soils in 1997. High DOC loads (25 mg/L), which would also impact on water treatment costs, moved through some soils. Significant loading of P moved through and over soils in both dissolved (0�5 mg/L) and particulate (0�3 mg/L) forms. Consequently, through-flow cannot be ignored as a contributor to P in streams and both dissolved and particulate P must be measured under these conditions to define the full impact of P. The findings from this research have implications for research on catchment management to restrict DOC and nutrient movement into waterways.

Sign in / Sign up

Export Citation Format

Share Document