Effect of Soil Texture on Water Movement of Porous Ceramic Emitters: A Simulation Study

Yaohui Cai,Junying Chen,Pute Wu,Delan Zhu,Lin Zhang,Xiao Zhao

doi:10.3390/w11010022

Abstract

Choosing reasonable design parameters for ceramic emitters used in subsurface irrigation is important for reducing the deep percolation of water and improving the water use efficiency. Laboratory experiments and numerical simulations with the HYDRUS-2D software were carried out to analyze the effect of soil texture on the infiltration characteristics of porous ceramic emitters used for subsurface irrigation. HYDRUS-2D predictions of emitter discharge in soil and wetting front are in agreement with experimental results, and the HYDRUS-2D model can be used to accurately simulate soil water movement during subsurface irrigation with ceramic emitters in different soil textures. Results show that soil texture has a significant effect on emitter discharge, soil matrix potential around the emitter, and wetting front. For 12 different soil textures, the aspect ratio of the wetting front is basically between 0.84–1.49. In sandy soil, the wetting front mainly appears as an ellipse; but in the clay, the wetting front is closer to a circle. As irrigation time increases, emitter discharge gradually decreases to a stable value; however, emitter discharge in different texture soils is quite different. In order to improve the crop water use efficiency in sandy soil, soil water retention can be improved by adding a clay interlayer or adding water retention agent, reducing the risk of deep percolation and improving the water use efficiency.

Highlights

Porous media are commonly used for seepage irrigation, and have a long history of increasing the water use efficiency (WUE), as well as the crop yield
1 At the beginning of irrigation, emitter discharge porous ceramic emitter buried in two different soils
10%, and the normalized root mean squared error (NRMSE) is less than 0.2, indicating that the HYDRUS-2D is highly suitable for simulating value is, the better the model fitting is

Summary

Introduction

Porous media are commonly used for seepage irrigation, and have a long history of increasing the water use efficiency (WUE), as well as the crop yield. Subsurface irrigation with ceramic devices has significant water-saving effects; there is potential for using ceramics in subsurface irrigation. Khan et al [1] found that the water use efficiency reached approximately 94–97% when pots with different structural sizes were used for irrigation. Zhang et al [2] found that tomatoes irrigated by ceramic emitters under a working pressure head of 0 cm achieved the highest yield, approximately. The working pressure head of a porous ceramic emitter was generally less than 100 cm [4,5]. The outflow from the emitter could replenish the soil moisture in real-time, effectively irrigating the soil

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Conclusion