title: Modeling solute transport by DLA in soils of northeastern Egypt.
abstract: Arid soils in Egypt display large variability in solute transport properties, causing problems in soil management. To characterize this variability, dye infiltration experiments were conducted on four plots representing three main soil types in northeastern Egypt. The plots represented both cultivated and uncultivated land use. The observed dye patterns displayed a large variability and especially the clay soils indicated a high degree of preferential flow. The loamy sand and sandy soils displayed a more uniform dye distribution indicating more homogeneous soil properties. The observed dye patterns were modeled using a diffusion limited aggregation (DLA) model. The DLA is a random walk model where model parameters can be optimized using genetic algorithms (GA). The DLA model reproduced the observed dye patterns for all soils in an excellent way. The best fit was obtained with a specific combination of directional random walk probabilities Pu, Pd, Pr, and Pl for each plot (correlation 0.97-0.99). To account for soil layers with different hydraulic properties a two layer DLA model was developed. For all plots the Pu (upward random walk probability) was higher for the upper more homogeneous soil layer. The overall results showed that spatial variability resulting from solute transport for the investigated soils can be modeled using a DLA approach.
authors: Civil Engineering Department, Faculty of Engineering, Port Said University, Port Fouad Port Said, Egypt.
authors: Yasser Ahmed
authors: YA
authors: Hamed
authors: Arid Land Research Center, Tottori University, Hamasaka Tottori, Japan.
authors: Hiroshi
authors: H
authors: Yasuda
authors: Department of Water Resources Engineering, Lund University, Lund, Sweden.
authors: Magnus
authors: M
authors: Persson
authors: Department of Water Resources Engineering, Lund University, Lund, Sweden; Center for Middle Eastern Studies, Lund University, Lund, Sweden.
authors: Ronny
authors: R
authors: Berndtsson
authors: Shapotou Desert Research and Experiment Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, PR China.
authors: Xin-ping
authors: XP
authors: Wang
mesh_terms: D000465:Algorithms; D004396:Coloring Agents / Q000737:chemistry; D004058:Diffusion; D004534:Egypt; D008962:Models, Theoretical; D012987:Soil / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D012987:Soil