Water Application Rate Determination for Optimizing Salt Leaching in Structured Soils

Presenter Information

Romulus Okwany
Scott B. Jones

Location

Eccles Conference Center

Event Website

http://water.usu.edu/

Start Date

3-27-2006 10:30 AM

End Date

3-27-2006 10:35 AM

Description

Solute transport is a critical process in the development and sustainability of irrigated agriculture for both environmental and ecological considerations. Leaching as a remedial and maintenance strategy for managing saline environments has been in practice for centuries. The water application rate has little influence on leaching efficiency in nonstructured, sandy soils but can play a significant role in structured or aggregated soils. We hypothesize that in structured soils the water application rate has direct impacts on the leaching efficiency. Our objectives were to apply solute transport models to measured breakthrough curves in order to study the effect of water application rate on leaching efficiency in columns of stable aggregates. Consideration was given to water use and time required for removal of the salt based on breakthrough curves and a mass balance approach. Simulations of varied flow velocities were carried out with Hydrus 1D to assess the leaching predictions under unsaturated flows. We anticipate locating a threshold pore water velocity above which diffusion-limited removal of the salts dictates the overall salt removal efficiency from aggregates. This efficiency may also be influenced by volumetric water content with reduced efficiencies at lower water content.

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Mar 27th, 10:30 AM Mar 27th, 10:35 AM

Water Application Rate Determination for Optimizing Salt Leaching in Structured Soils

Eccles Conference Center

Solute transport is a critical process in the development and sustainability of irrigated agriculture for both environmental and ecological considerations. Leaching as a remedial and maintenance strategy for managing saline environments has been in practice for centuries. The water application rate has little influence on leaching efficiency in nonstructured, sandy soils but can play a significant role in structured or aggregated soils. We hypothesize that in structured soils the water application rate has direct impacts on the leaching efficiency. Our objectives were to apply solute transport models to measured breakthrough curves in order to study the effect of water application rate on leaching efficiency in columns of stable aggregates. Consideration was given to water use and time required for removal of the salt based on breakthrough curves and a mass balance approach. Simulations of varied flow velocities were carried out with Hydrus 1D to assess the leaching predictions under unsaturated flows. We anticipate locating a threshold pore water velocity above which diffusion-limited removal of the salts dictates the overall salt removal efficiency from aggregates. This efficiency may also be influenced by volumetric water content with reduced efficiencies at lower water content.

https://digitalcommons.usu.edu/runoff/2006/AllPosters/7