Surface Ponding of Coarse-textured Soils under Irrigation with a Line of Surface Emitters

✍ Scribed by E.G. Youngs; P.B. Leeds-Harrison; A. Alghusni

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 135 KB
• Volume: 73
• Category: Article
• ISSN: 0021-8634
• DOI: 10.1006/jaer.1998.0392

✦ Synopsis

The use of drip irrigation techniques on coarsetextured soils can lead to predominantly vertical movement of water down the soil pro"le with very little horizontal spread unless #ow rates from the emitters are high enough to cause water to pond over a large area on the soil surface. Tank experiments were conducted with a line of emitters irrigating the surface of coarse and "ne sands. The ponded surface area that developed on the sand surface depended both on the emitter #ow rate and on the hydraulic properties of the sand. It became constant after some time when the rate of surface spreading became zero and all the irrigation water in"ltrated into the soil. The width of the ultimate ponded strip was described well by an expression given by a theoretical analysis for the width of a #at-bottomed canal with water seeping at zero head with a #ow rate that of the emitter. However, the width of the soil strip wetted either side of the ponded strip continued to advance during the experiments and did not reach the theoretical ultimate value given in the analysis. In the comparison between measurements and theoretical results, values of the Green and Ampt in"ltration parameters used in the theory were obtained in separate tests. It is suggested that the theoretical analysis provides criteria for the design of drip irrigation systems in coarse-textured soils.