Impacts of Floods on Organic Carbon Concentrations in Alluvial Soils along Hydrological Gradients Using a Digital Elevation Model (DEM)

Abstract

This study examines the spatial distribution of the organic carbon found in alluvial soils affected by successive floods. In flood zones, very little is known of the processes associated with the development of soils subjected to frequent flooding, in particular with respect to the accumulation of litter and organic carbon concentrations. The aim of this study is to better understand the distribution of organic carbon based on various hydrological gradients associated with flood recurrence. A digital elevation model was developed from LIDAR data to assess the microtopography of the site, and further delineate floodplains and no-flood zones. Various soil properties were considered in addition to organic carbon, such as pH, soil bulk density, litter, drainage, and topographic levels (elevation). The results show that the soils in the frequent-flood zones (FFz, recurrence of 0-20 years) have significantly less total organic carbon than the soils in the no-flood zones (NFz) and the moderate flood zones (MFz,. Average values obtained for the surface horizons (0-20 cm) vary by 1.74%˘0.85% (FFz), 3.34%˘1.09% (MFz) and 3.54%˘1.77% (NFz), respectively. The absence of ground litter in the frequent flood zones helps decrease the input of organic matter in the surface horizons and progressively results in soil depletion.

Physical parameters of Fluvisols on flooded and non-flooded terraces

“…The highest content of SOC in the surface layer under forest is usually explained with the high level of soil organic matter (SOM) input (Gajić, 2013). The average value of SOC for the 0-20 cm soil layer in profile 3 is 1.72% and it is comparable to the results for frequent flood zones (SOC=1.74%) obtained by Saint-Laurent et al (2016) for the region of southern Québec, Canada. The lower average values of SOC for this layer in the non-flooded terrace (2.00% for profile 2 and 0.69% for profile 1) than those reported by SOC -soil organic carbon, BD -bulk density, PD -particle density, P t -total porosity, P r -volume of pores with effective radius r: 0<0.1 µm (wilting point), P r 0.1÷5 µm (plant available water capacity), P r >30 µm (drainage aeration pores), K f -saturated hydraulic conductivity.…”

“…The method of nitrogen adsorption isotherms was used to determine pores of an equivalent radius 0.1-0.001 μm (Greeg and Sing, 1982;Ościk, 1982). The isotherms were measured using a Sorptomatic (model SO 1990, Fisons Instruments) at the temperature of liquid nitrogen (-195.82°C) in the range of relative pressures of nitrogen from p/p o = 0.004 to p/p o = 0.997.…”

“…The isotherms were measured using the vacuum chamber method as described above; however, sulphuric acid at stepwise increasing concentrations was used (decrease of p/p o =relative vapour pressure; p is the equilibrium vapour pressure, and p o is the saturated vapour pressure at temperature T). We assumed that the micropore radius, R mic , in the capillary condensation process is related to the vapour pressure p by the Kelvin equation for the hemispherical meniscus with zero water/solid contact angle and that the condensation in micropores occurs above p/p o =0.35 (below this value, surface adsorption processes dominate) (Ościk, 1982). Thus the total micropore volume (V mic , total) was taken as the volume of adsorbed water at the maximum p/ p o value minus the volume of adsorbed water at p/p o =0.35.…”

Soil–landscape variability: mapping and building detail information for soil management

“…The surficial flow led to shallow upslope soils (<50 cm), and the eroded materials were deposited down slope, resulting in deep soils (Tongway & Ludwig, ; Vasu et al ., ) as manifested in most soils of the study area. The variability of soil properties in undulating topography could be attributed to mass movement, periodic flooding and deposition of multiple sources of materials (Huggett, ; Saint‐Laurent et al ., , ). On the other hand, uptake and accumulation of soil nutrients in tree biomass can be significant factors for driving soil nutrient variation within a single mapping unit (Johnson & Todd, ).…”

Monitoring of antibiotics and Atrazine in tile drained Landscapes.

“…The impact of sediment organic C on the sorption of TYL, SMZ, and ATZ is shown in (Figure 4.7). The transport of sediment has the ability to improve or deplete the organic carbon content of soil depending on the total organic content (TOC) of the sediment (Saint-Laurent et al, 2016). The impact of sediment on TOC is important to the fate and transport of organic compounds such as antibiotics.…”