An Improved Empirical Model for Estimating the Geometry of the Soil Wetting Front with Surface Drip Irrigation

Abstract

Wetting pattern geometry is useful in determining the spacing between emitters and the irrigation time in drip irrigation systems. This research aimed to generate an empirical model to estimate the width and depth of the wetting front in surface drip irrigation based on experimental tests in a cube-shaped container with transparent walls in soils with a sandy clay loam texture, with hydraulic conductivities from 2.316 to 3.945 cm h−1, and organic matter contents from 1.7 to 2.8%, and different irrigation conditions: discharge rates of 1.44, 2.90, 3.00, 3.75, and 4.00 L h−1, initial moisture levels between permanent wilting point and field capacity, and irrigation times from 0.58 to 9.50 h. The experimental conditions and the strategy for measuring the wetting front and soil moisture are detailed so the experiment is verifiable. The proposed model performed better than five other empirical models, with average values of 3 cm for the root mean square error and 0.88 for the Nash and Sutcliffe efficiency coefficient. The generated model is efficient and simple and can be a very useful tool for the design and operation of surface drip irrigation systems in soils with conditions similar to those of this study.

Eco-hydrological modeling of soil wetting pattern dimensions under drip irrigation systems

“…Interpretations from field observations have been combined with linear or nonlinear regression and dimensional analysis to create empirical models that can be tested for accuracy [ 49 , 50 ]. The rationale of the empirical models was expressed to estimate one of the parameters such as soil moisture content, the radius of wetted soil bulb, volume of wetted soil bulb, depth of soil wetting, boundaries and shape of wetted soil volume, which is a function of the total amount of water applied, irrigation measure, soil porosity, and soil physical and hydraulic properties (soil bulk density, percent sand, silt, and clay, average change in soil water content, initial soil moisture content, saturated soil hydraulic conductivity, or steady-state infiltration rate) using regression analysis (linear and nonlinear), dimensional analysis, and artificial neural networks (ANNs) from field investigations [ 2 , 51 ].…”

“…As the population density is increasing daily and water consumption is increasing, the irrigation system needs to be modified to produce more with less water and more food, while the agricultural productivity of soil and water resources is suffering. Microirrigation technology is widely used and applied worldwide [ 2 ]. In areas where water resources are becoming scarce and problematic, drip irrigation technology leads to “more yield per drop of water” for more sustainable agriculture [ 3 ].…”

Development of a soil wetting pattern estimation model for drip irrigation

“…Therefore, the development of an empirical model including initial soil water content that can predict the soil wetting patterns under drip irrigation would provide a convenient and accurate method to quantify the horizontal and vertical wetting front (Cristóbal-Muñoz et al 2022). Moazenzadeh et al (2022) believed the soil water content was helpful in determining irrigation depth and frequency, and evaluated the performance of optimization algorithms in estimating soil water content.…”