Evaluating Performance of Artificial Capillary Barriers to Improve Root Zone Conditions Using Hydrus.

In many arid and/or semi-arid regions where water is scarce, it is critical to avoid root zones to be affected by salt and to reduce deep percolation below root zones. An artificial capillary barrier (CB), which consists with a layer of gravels, has been used to improve root zone condition for crop production. However, it is not fully evaluated how much water can be saved if CB is installed. In addition, CB can be easily broken when it is not carefully designed. The long term stability of CB needs to be well understood.

The main objective of this study is therefore to numerically evaluate the performance of CB while cultivating crops using HYDRUS program. HYDRUS allows one to simulate water flow and solute/heat transport in saturated and unsaturated soils. Hydraulic properties of CB used in numerical simulation were determined in the lab. Different irrigation schedules were then compared through numerical simulation to determine optimum amount of water to be applied. This study demonstrates the usefulness of numerical simulation to evaluate the performance of CB.