Comparison of numerical, analytical, and empirical models to estimate wetting patterns for surface and subsurface drip irrigation

Abstract

Due to increasing competition for water resources by urban, industrial, and agricultural users, the proportion of agricultural water use is gradually decreasing. To maintain or increase agricultural production, new irrigation systems, such as surface or subsurface drip irrigation systems, will need to provide higher water use efficiency than those traditionally used. Several models have been developed to predict the dimensions of wetting patterns, which are important to design optimal drip irrigation system, using variables such as the emitter discharge, the volume of applied water, and the soil hydraulic properties. In this work, we evaluated the accuracy of several approaches used to estimate wetting zone dimensions by comparing their predictions with field and laboratory data, including the numerical HYDRUS-2D model, the analytical WetUp software, and selected empirical models. The soil hydraulic parameters for the HYDRUS-2D simulations were estimated using either Rosetta for the laboratory experiments and inverse analysis for the field experiments. The mean absolute error (MAE) was used to compare the model predictions and observations of wetting zone dimensions. MAE for different experiments and directions varied from 0.87 to 10.43 cm for HYDRUS-2D, from 1 to 58.1 cm for WetUp, and from 1.34 to 12.24 cm for other empirical models. Communicated by J. Ayars.

Drip Irrigation Scheduling Using Hydrus 2‐D Numerical Model Application for Strawberry Production in South‐West Spain

“…The goodness of fit between modelled and observed wetting patterns was supported by the accuracy measures shown in Table . These findings are consistent with Kandelous and Šimůnek () who found RMSE values between 2.1 and 3.87 cm for wetting pattern (radial and vertical distances) calibration with field data and between 0.98 and 4.36 for calibrations with lab measurements. In both cases, they reported r 2 values in the range of 0.94 and 0.99.…”

“…These indices and the correlation coefficient are frequently used in different calibration studies of modelled wetting patterns (Skaggs et al ., ; Kandelous and Šimůnek, ; Samadianfard et al ., ; Bandenay Egoávil, ).…”

Root growth and distribution in sugarcane cultivars fertigated by a subsurface drip system

“…Nevertheless it is important to highlight that food and bioenergy demand is also increasing and water use efficiency in agricultural systems must be improved by using the most appropriate irrigation method and water management. The subsurface drip irrigation system contributes to water savings, maintaining or even increasing the agricultural production as compared to other irrigation methods (Kandelous & Šimůnek, 2010) and allows the nutrient application by fertigation at the right time and place, increasing the nutrient uptake efficiency and reducing its losses by leaching.…”

Modeling Water and Nutrient Movement in Sandy Soils Using HYDRUS‐2D

“…Soil hydraulic parameters of this model can be represented analytically using different hydraulic models (Brooks and Corey, 1964; van Genuchten, 1980). Several researchers have used HYDRUS in irrigated systems in the last 17 yr (Gärdenäs et al, 2005; Boivin et al, 2006; Fernández‐Gálvez and Simmonds, 2006; Hanson et al, 2006; Šimůnek and Hopmans, 2009; Kandelous and Šimůnek, 2010a, 2010b; Kandelous et al, 2011). Despite problems associated with identification of the actual physical processes when conducting simulation, Pang et al (2000) found that the HYDRUS model described soil water contents with minor discrepancies.…”