Newly-amended biochar particles decrease erodibility and improve hydraulic soil properties

2021 ◽  
Author(s):  
Steffen Seitz ◽  
Sandra Teuber ◽  
Christian Geissler ◽  
Philipp Goebes ◽  
Thomas Scholten
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Erosion ◽  
Soil Water ◽  
Water Retention ◽  
Early Stage ◽  
Substrate Surface ◽  
Hydrothermal Carbonization ◽  
Future Research ◽  
Small Scale ◽  
Soil Water Retention

<p>Biochar is charcoal obtained by thermal decomposition of biomass through pyrolysis. The amendment of biochar changes chemical, but also physical properties of soils such as aggregation and texture. Thus, it is assumed that it can also affect soil erosion and erosion-related processes like the movement of water within the soil. In this study, we investigated how biochar particles change erodibility by rain splash instantly after application, as well as the initial movement of soil water.</p><p>Therefore, we conducted a small-scale laboratory experiment with two sieved substrates and using hydrothermal carbonization (HTC)-char and Pyrochar. Soil erodibility was determined with Tübingen splash cups under simulated rainfall, soil hydraulic conductivity was calculated from texture and bulk soil density, and soil water retention was measured using the negative and the excess pressure methods.</p><p>Results showed that the addition of biochar significantly reduced initial soil erosion in coarse sand and silt loam immediately after biochar application. Furthermore, biochar particles were not preferentially removed from the substrate surface. Increasing biochar particle sizes partly showed decreasing erodibility of substrates. Moreover, biochar amendment led to improved hydraulic conductivity and soil water retention regarding soil erosion control, with increasing application rates. It became clear that these effects are already detectable in a very early stage, and without long-term incorporation of biochar into soils. We could further show that different biochar types have varying impacts on investigated parameters due to their chemical properties and sizes, and future research should include varying biochars produced with different production methods.</p><p>In conclusion, this study showed that biochar amendments have the potential to reduce soil erosion by water from a very early stage. This mechanism adds a further ecosystem service to the list of useful impacts of biochar application on agriculture.</p>

scholarly journals How Do Newly-Amended Biochar Particles Affect Erodibility and Soil Water Movement?—A Small-Scale Experimental Approach

Soil Systems ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 60 ◽  
Author(s):  
Steffen Seitz ◽  
Sandra Teuber ◽  
Christian Geißler ◽  
Philipp Goebes ◽  
Thomas Scholten
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Erosion ◽  
Soil Water ◽  
Water Retention ◽  
Water Movement ◽  
Early Stage ◽  
Substrate Surface ◽  
Small Scale ◽  
Soil Water Retention ◽  
Biochar Amendment

Biochar amendment changes chemical and physical properties of soils and influences soil biota. It is, thus, assumed that it can also affect soil erosion and erosion-related processes. In this study, we investigated how biochar particles instantly change erodibility by rain splash and the initial movement of soil water in a small-scale experiment. Hydrothermal carbonization (HTC)-char and Pyrochar were admixed to two soil substrates. Soil erodibility was determined with Tübingen splash cups under simulated rainfall, soil hydraulic conductivity was calculated from texture and bulk soil density, and soil water retention was measured using the negative and the excess pressure methods. Results showed that the addition of biochar significantly reduced initial soil erosion in coarse sand and silt loam immediately after biochar application. Furthermore, biochar particles were not preferentially removed from the substrate surface, but increasing biochar particle sizes partly showed decreasing erodibility of substrates. Moreover, biochar amendment led to improved hydraulic conductivity and soil water retention, regarding soil erosion control. In conclusion, this study provided evidence that biochar amendments reduce soil degradation by water erosion. Furthermore, this effect is detectable in a very early stage, and without long-term incorporation of biochar into soils.

Method for Quick Prediction of Hydraulic Conductivity and Soil-Water Retention of Unsaturated Soils

2018 ◽  
Vol 2672 (52) ◽  
pp. 108-117 ◽  
Author(s):  
Shaoyang Dong ◽  
Yuan Guo ◽  
Xiong (Bill) Yu
Keyword(s):  
Finite Element ◽  
Hydraulic Conductivity ◽  
Soil Properties ◽  
Soil Water ◽  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Hydraulic Properties ◽  
Water Retention ◽  
Characteristic Curve ◽  
Soil Water Retention

Hydraulic conductivity and soil-water retention are two critical soil properties describing the fluid flow in unsaturated soils. Existing experimental procedures tend to be time consuming and labor intensive. This paper describes a heuristic approach that combines a limited number of experimental measurements with a computational model with random finite element to significantly accelerate the process. A microstructure-based model is established to describe unsaturated soils with distribution of phases based on their respective volumetric contents. The model is converted into a finite element model, in which the intrinsic hydraulic properties of each phase (soil particle, water, and air) are applied based on the microscopic structures. The bulk hydraulic properties are then determined based on discharge rate using Darcy’s law. The intrinsic permeability of each phase of soil is first calibrated from soil measured under dry and saturated conditions, which is then used to predict the hydraulic conductivities at different extents of saturation. The results match the experimental data closely. Mualem’s equation is applied to fit the pore size parameter based on the hydraulic conductivity. From these, the soil-water characteristic curve is predicted from van Genuchten’s equation. The simulation results are compared with the experimental results from documented studies, and excellent agreements were observed. Overall, this study provides a new modeling-based approach to predict the hydraulic conductivity function and soil-water characteristic curve of unsaturated soils based on measurement at complete dry or completely saturated conditions. An efficient way to measure these critical unsaturated soil properties will be of benefit in introducing unsaturated soil mechanics into engineering practice.

scholarly journals A numerical study on the effect of salinity on stability of an unsaturated railway embankment under rainfall

2020 ◽  
Vol 195 ◽  
pp. 01004
Author(s):  
Ali Kolahdooz ◽  
Hamed Sadeghi ◽  
Mohammad Mehdi Ahmadi
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Water ◽  
Water Retention ◽  
Numerical Study ◽  
Water Retention Curve ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Unsaturated Hydraulic Conductivity ◽  
Influence Of Water ◽  
Dispersive Soils

Dispersive soils, as one of the main categories of problematic soils, can be found in some parts of the earth, such as the eastern-south of Iran, nearby the Gulf of Oman. One of the most important factors enhancing the dispersive potential is the existence of dissolved salts in the soil water. The main objective of this study is to explore the influence of water salinity on the instability of a railway embankment due to rainfall infiltration. In order to achieve this goal, the embankment resting on a dispersive stratum is numerically modeled and subjected to transient infiltration flow. The effect of dispersion is simplified through variations in the soil-water retention curve with salinity. The measured water retention curves revealed that by omitting the natural salinity in the soil-water, the retention capability of the soil decreases; therefore, the unsaturated hydraulic conductivity of the soil stratum will significantly decline. According to the extensive decrease in the hydraulic conductivity of the desalinated materials, the rainfall cannot infiltrate in the embankment and the rainfall mostly runs off. However, in the saline embankment, the infiltration decreases the soil suction; and consequently, the factor of safety of the railway embankment decreases.

The effect of natural seed coatings of Capsella bursa-pastoris L. Medik. (shepherd’s purse) on soil-water retention, stability and hydraulic conductivity

2014 ◽  
Vol 387 (1-2) ◽  
pp. 167-176 ◽  
Author(s):  
Wenni Deng ◽  
Paul D. Hallett ◽  
Dong-Sheng Jeng ◽  
Geoffrey R. Squire ◽  
Peter E. Toorop ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Water ◽  
Water Retention ◽  
Soil Water Retention

scholarly journals An Environmentally Friendly Soil Amendment for Enhancing Soil Water Availability in Drought-Prone Soils

Agronomy ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 133
Author(s):  
Ting Yang ◽  
Xuguang Xing ◽  
Yan Gao ◽  
Xiaoyi Ma
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Water ◽  
Water Retention ◽  
Critical Role ◽  
Saturated Hydraulic Conductivity ◽  
Soil Water Retention ◽  
Semiarid Areas ◽  
Arid And Semiarid Areas ◽  
Relative Change ◽  
Arid And Semiarid

Applying soil amendments plays a critical role in relieving water stress in arid and semiarid areas. The natural clay mineral attapulgite (ATP) can be utilized to adjust the balance of water and soil environment. In this study, we investigated four different particle size distribution typical soils in the Loess Plateau: (1) lou soil (LS), (2) dark loessial soil (DS), (3) cultivated loess soil (CS), (4) sandy soil (SS). Five ATP application rates (0, 1%, 2%, 3%, and 4%) were selected to test the effect of ATP on the soil water retention curve, soil saturated hydraulic conductivity, and soil structure. The results showed that applied ATP significantly increased the soil clay content, and the relative change of SS with 3% ATP applied increased by 53.7%. The field water holding capacity of LS, DS, CS, and SS with 3% ATP applied increased by 8.9%, 9.6%, 18.2%, and 45.0%, respectively. Although applied ATP reduced the saturated hydraulic conductivity, the values of CS and SS were opposite when the amount of ATP applied was >3%. The relative change in the amount of 0.25–1 mm soil water-stable aggregates of SS was 155.9% when 3% ATP was applied. Applied ATP can enhance soil water retention and soil stability, which may improve limited water use efficiency and relieve soil desiccation in arid and semiarid areas or similar hydrogeological areas.

Mitigating Rainfall-Induced Sediment Hazard and Soil Erosion Using Organic Amended Soil Improvement

2016 ◽  
Vol 11 (6) ◽  
pp. 1228-1237
Author(s):  
Khonesavanh Vilayvong ◽  
◽  
Noriyuki Yasufuku ◽  
Kiyoshi Omine ◽  
◽  
...  
Keyword(s):  
Soil Erosion ◽  
Soil Water ◽  
Soil Loss ◽  
Water Retention ◽  
Soil Condition ◽  
Soil Improvement ◽  
Organic Wastes ◽  
Soil Water Retention ◽  
Experimental Conditions ◽  
Application Rates

Soil-organic amendment (SOA) is one of the sustainable soil improvement measures to mitigate climate change related issues such as rainfall-induced hazard and soil erosion. Organic wastes particularly compost and biochar can be reused and recycled into viable resources. However, there are limited data on incoporating organic wastes into a soil that is susceptible to erosion by rainfall. Therefore, objective of this study is to investigate properties of a soil from Okinawa prefecture (Kunigami maaji) that are associated with resisting ability against artificial rainfall intensities of 30, 60, 90 and 120 mm/h after adding two organic matters: household-derived compost and rice hush-derived biochar. The properties were soil-water retention, runoff, soil loss, infiltration and electrical conductivity. The compost was mixed with the soil at application rates of 0.5, 1.0, 1.5 and 2.0 kg/m2. The compost of 1.0 kg/m2was mixed with the soil and the biochar at application rates of 1, 3, and 5% by total weight. Experimental results indicate that the soil water retention properties of the soil were improved by the treatment of compost and biochar. However, soil loss was not significantly reduced under initially saturated soil condition, applied rainfall intensities, testing duration and experimental conditions. The results of this study could be used as baseline data for evaluating correlation between properties of soil water retention curves to soil erosion.

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