Soil moisture based automatic irrigation control system for a greenhouse

Abstract

Water stress continues to be a major factor that affects agricultural productivity in arid and semi-arid regions, which are
characterized by high annual rainfall variability. Water-saving practices and sound water management strategies are urgently
required to ensure the long-term viability of the agricultural industry in these regions. Automated irrigation systems provide
greater control over the quantity of water applied which eventually improves water use efficiency. Thus, a new control strategy
utilizing a control system made from mostly off-the-shelf electronic components was developed for controlling irrigation of a
tomato crop in a greenhouse. The newly designed soil moisture-based automatic irrigation controller (SMAIC) managed water
application using moisture sensors whereby data pertaining to soil moisture was used for the prediction of irrigation timing.
SMAIC saved water by up to 74% compared to local farmer practice for greenhouse tomatoes. For all the treatments
implemented, the yield was not significantly different. Irrigation water use efficiency (IWUE) was significantly higher in the
SMAIC treatment.