A Model-Based Real-Time Decision Support System for Irrigation Scheduling to Improve Water Productivity

Chen Chen,Li Li,Zeng Zeng,Ma Ma,Gu Gu,Gui Gui,Sima Sima,Qi Qi

doi:10.3390/agronomy9110686

Abstract

A precisely timed irrigation schedule to match crop water demand is vital to improving water use efficiency in arid farmland. In this study, a real-time irrigation-scheduling infrastructure, Decision Support System for Irrigation Scheduling (DSSIS), based on water stresses predicted by an agro-hydrological model, was constructed and evaluated. The DSSIS employed the Root Zone Water Quality Model (RZWQM2) to predict crop water stresses and soil water content, which were used to trigger irrigation and calculate irrigation amount, respectively, along with forecasted rainfall. The new DSSIS was evaluated through a cotton field experiment in Xinjiang, China in 2016 and 2017. Three irrigation scheduling methods (DSSIS-based (D), soil moisture sensor-based (S), and conventional experience-based (E)), factorially combined with two irrigation rates (full irrigation (FI), and deficit irrigation (DI, 75% of FI)) were compared. The DSSIS significantly increased water productivity (WP) by 26% and 65.7%, compared to sensor-based and experience-based irrigation scheduling methods (p < 0.05), respectively. No significant difference was observed in WP between full and deficit irrigation treatments. In addition, the DSSIS showed economic advantage over sensor- and experience-based methods. Our results suggested that DSSIS is a promising tool for irrigation scheduling.

Highlights

Improving water use efficiency (WUE) has become an important strategy in dealing with drought in zones with limited water resources
The Decision Support System for Irrigation Scheduling (DSSIS), using model-predicted real-time water stress as a threshold to trigger irrigation, performed the best with the highest water productivity (WP), the highest cotton yield, and a significant reduction in total irrigation amount compared to the experience-based method
Use of DSSIS under deficit irrigation saved the greatest amount of irrigation water, increased yield by 4.0%, and enhanced WP by 80.6% compared to experience-based full irrigation

Summary

Introduction

Improving water use efficiency (WUE) has become an important strategy in dealing with drought in zones with limited water resources. The exploitation of available fresh water, especially groundwater resources, has seriously hindered sustainable agriculture development and even economic growth in arid and semi-arid regions. Modern technologies are helping to achieve efficient water use in these. Agronomy 2019, 9, 686 regions [1]. One of the major water users, agriculture, faces intense competition from other major water users, especially the industrial sector [2]. China’s agricultural water use accounts for about 70% of its total water consumption. The relatively low crop yield and WUE in many regions is the result of unreasonable irrigation and fertilizer application rates [3,4]

Objectives

Methods

Results

Conclusion