Dynamic Simulation Tool of fertigation in drip irrigation subunits

Abstract

Agriculture consumes approximately 95 million tonnes of fertilizers and 97,000 tonnes of active ingredients of pesticides and herbicides. Reducing external input systems can result in significant economic, social and environmental impact. Therefore, establishing an optimal fertigation schedule is essential to achieve efficient drip irrigation management and, therefore, achieve an optimal irrigated agriculture management system that ensures productive, environmental and economic viability. The objective of this study was to develop a decision support system (DSS) to facilitate farmers’ decision-making process and optimize the design and management of farm fertigation scheduling. Implemented in MATLAB®, FERTI-DRIP, was tested in a regular irrigation subunit and in an irregular irrigation subunit of a real water user association. Both irrigation subunits were tested with two irrigation emitter types: pressure-compensating emitters and non-pressure-compensating emitters. Thus, FERTI-DRIP was applied to four scenarios to analyse the effect of the size and shape of the irrigation subunit on the fertigation process. The effect of the pressure head in the irrigation subunit and the effect of the fertilizer dynamics during the fertigation event were also analysed. FERTI-DRIP allows users to compute fertilizer quality parameters to determine how to implement fertigation. FERTI-DRIP also allows users to accurately select pre-fertigation and post-fertigation processes to optimize hydraulic stability at the beginning of the fertigation event and ensure that there is no fertilizer remaining in the irrigation system after the fertigation event. FERTI-DRIP can be very helpful for start-time irrigation events, such in the case of sandy soils where pulse drip irrigation should be performed.