Variable-Rate Irrigation in Diversified Vegetable Crops: System Development and Evaluation

Abstract

Diversified cropping systems offer an alternative to sustainable agriculture, but they present high spatial variability. This study aims to develop and evaluate an automated irrigation system and a variable-rate water application for areas with diversified vegetable crops. The prototype comprises a mobile drip line, a winding reel, and an electronic control system. The drip line irrigates plants individually, with irrigation depths along the beds controlled by the displacement speed and between beds by adjusting the timing of electrical pulses to activate the water flow control valves. To evaluate the drip line, irrigation depths were defined for different crops, followed by performance assessments, which included evaluating the uniformity (Christiansen’s Uniformity Coefficient—CUC) of the line under constant and variable rates. A hydraulic evaluation of the system was also carried out, as well as the calculation of the potential irrigable area. The drip line showed CUC ≥96% for depths under a constant rate and 95% for depths under a variable rate. The application efficiency reached 93.4% for a degree of suitability of 83%, considering variable depths along and between beds. The potential irrigable area obtained was 360 m2 day−1. The developed drip line effectively meets the spatial variability of crop water requirements in diversified cropping systems by adopting the variable-rate irrigation technique. The control of irrigation depth through valve activation via electrical pulses allows for the application of variable depths between the beds.