Evaluating Supplementary Water Methodology with Saturated Soil Irrigation for Yield and Water Productivity Improvement in Semi-Arid Rainfed Rice System, Burkina Faso

Abstract

Saturated soil irrigation (SSI) has been reported as a great technique that increases water productivity in fully irrigated rice cultivation. However, this technique should be employed in a dry prone area where rainfalls fail to fulfill rice water requirements and fill up reservoirs for sufficient irrigation. Therefore, an experiment was conducted to identify the most effective complementary irrigation that restores soil moisture to saturation and increases water productivity with fewer yield expenses. The study used a complete randomized blocks design with four replications and four soil saturation treatments: Sat200% (farmer practice), Sat160%, Sat120%, and Sat80%. In Sat160%, Sat120%, and Sat80% irrigation was applied once a week in the absence of rainfall. In Sat200%, water was daily applied except the day of rain. The results showed that reductions in soil saturation decreased plant height, tillers, and leaves number by 10%, 18%, and 14%, respectively. Yield and components were reduced between 26.09% and 4.8%. Weekly soil saturation at 120% exhibited greater irrigation productivity (0.69 kg/m3), rainwater productivity (1.02 kg/m3), and water-saving (90.53%) with less production penalty (5 × 10−3 kg/m3). We advocate that saturated soil irrigation should be recommended in the rainfed rice system as a drought mitigation measure in semi-arid conditions.