Event Title

Spatiotemporal variability of soil hydraulic properties under drainage and recharge cycles

Start Date

30-8-2017 10:15 AM

End Date

30-8-2017 10:30 AM

Description

Abstract.

The installation of drainage systems can cause anthropic evolution of the soil profile. Natural consolidation, filtration and clogging of soil pores by colloidal particles may be accelerated by water management practices, such as irrigation, drainage and flooding, and could reduce the drainage capacity of the soil. X-ray tomography can be used to describe soil hydraulic properties at the small scale and to study several physical soil processes, especially those related to the migration of colloidal particles and consolidation. Wavelet analyses can decompose an observed time series of soil matric potential into various components that can be used to determine the temporal periodicity of drainage and recharge. The main objective of this study was to analyze the spatiotemporal variability in the hydraulic properties of a sandy soil and the time series of matric potential during repeated cycles of drainage and recharge from the bottom of a soil profile using a medical X-ray computerized tomography (CT) scanner and wavelet transforms. A soil column laboratory experiment was set up to monitor the pressure head, water inflow and outflow, and the movement of the tracers KBr and ZrO2. Tomographic scans have been used to analyze the spatiotemporal variability in the soil hydraulic properties. The results show that repeated drainage and recharge cycles greatly affect the evolution of soil hydraulic properties by reducing drainage and capillary capacities. Knowledge of the mechanisms responsible for this human-induced soil genesis is important for water management in agricultural systems. This information may allow prediction of soil evolution according to soil texture, drainage system design and water management, thereby anticipating and possibly controlling problems related to soil hydrodynamics.

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Aug 30th, 10:15 AM Aug 30th, 10:30 AM

Spatiotemporal variability of soil hydraulic properties under drainage and recharge cycles

Abstract.

The installation of drainage systems can cause anthropic evolution of the soil profile. Natural consolidation, filtration and clogging of soil pores by colloidal particles may be accelerated by water management practices, such as irrigation, drainage and flooding, and could reduce the drainage capacity of the soil. X-ray tomography can be used to describe soil hydraulic properties at the small scale and to study several physical soil processes, especially those related to the migration of colloidal particles and consolidation. Wavelet analyses can decompose an observed time series of soil matric potential into various components that can be used to determine the temporal periodicity of drainage and recharge. The main objective of this study was to analyze the spatiotemporal variability in the hydraulic properties of a sandy soil and the time series of matric potential during repeated cycles of drainage and recharge from the bottom of a soil profile using a medical X-ray computerized tomography (CT) scanner and wavelet transforms. A soil column laboratory experiment was set up to monitor the pressure head, water inflow and outflow, and the movement of the tracers KBr and ZrO2. Tomographic scans have been used to analyze the spatiotemporal variability in the soil hydraulic properties. The results show that repeated drainage and recharge cycles greatly affect the evolution of soil hydraulic properties by reducing drainage and capillary capacities. Knowledge of the mechanisms responsible for this human-induced soil genesis is important for water management in agricultural systems. This information may allow prediction of soil evolution according to soil texture, drainage system design and water management, thereby anticipating and possibly controlling problems related to soil hydrodynamics.