Empirical modelling of wetting patterns in a controlled drip irrigation system for sandy loam soils

Abstract

The soil wetting pattern is an important factor to fulfil the adequacy of water requirements in a controlled drip irrigation system. The soil wetting pattern is a parameter that is considered in the installation of irrigation systems and control instruments in the field. This study aimed to developed estimate vertical and horizontal soil wetting in the application of control systems using soil moisture sensor in drip irrigation systems. This research conducted in laboratory experiments with surface drip irrigation involved soil sample from pepper plantation, three discharge rates, and 26 soil moisture sensors. The empirical model provides estimated the soil wetted as a parameter of application time, emitter discharge, soil bulk density, initial soil moisture content, and saturated hydraulic conductivity. The development of empirical formulas for predicting wetted radius at different soil depths is carried out by non-linear regression analysis to obtain empirical best-fit coefficients. The empirical model of this study can estimate the full wetting pattern with acceptable accuracy and performs that represent a good performance of a controlled drip irrigation system. The result of performance appraisal validation for the wetted radius and wetted depth on sandy loam soils was assessed based on the lowest mean error was -2.86 and -0.284 cm as well as the highest efficiency model was 0.959 and 0.857 respectively.