Investigation of the Wetting Front Distribution in Vertically Layered Arid Soils under Drip Irrigation

Document Type : Original Article

Authors

1 Ph.D in Irrigation and Drainage,Bachelor of Civil Engineering Student, Non-Profit Higher Education Institute, Rah Danesh, Babol

2 Dept. of Water Engineering, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran.

3 ph.d Science Technology and Innovation Policy, university of Mazandaran, Iran.

10.22044/jhwe.2025.15639.1051

Abstract

Soil wetting front depends on various factors, including soil texture, emitter flow rate, land slope, and volume of irrigation water. Accurate estimation of the curved shape of the wetting front distribution helps to know how much advanced water and liquid fertilizers have transported in porous media. A cube-shaped physical model was built, and the experiments were performed at emitter flow rates of 2, 4, and 8 L/h and slopes of 0, 10, and 20% on 4 soil samples. Samples 1 and 2 were homogeneous soils, and samples 3 and 4 were vertically layered soils. The homogeneous soil samples had light, loamy sand (L) and heavy, clay (H) textures. The vertically layered soil samples included three layers. The results showed that the change in soil texture from L to LHL increased the average maximum wetting front radius downstream of the emitter (R_0^-) At the mentioned flow rates by 18, 24 and 35%, respectively. The change in soil texture from L to LHL decreased the mean depth of the wetting front (D) by 16%, 28%, and 40%, respectively. With changing from H to HLH, the mean R_0^- The mentioned flow rates decreased by 27, 32, and 41%, respectively, and the mean D increased by 22, 35, and 53%, respectively. Based on statistical analysis, results indicated that there were significant differences (p<0.05) between the layered and homogenous soils. Changing the soil texture around the emitter from L to H, especially on sloping lands, increases the wetting front radius and decreases its depth. Whereas changing the texture from H to L decreases the wetting front radius and increases its depth, thus reducing water loss.

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