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

Aimé Sévérin Kima,Bernard Bacyé,Hervé Nandkangré,Yu-Min Wang,Paule A W Ouédraogo,Seydou Traore,Wen-Guey Chung,Etienne Kima,Ousmane Traore

doi:10.3390/su12124819

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.

Highlights

Concerns are mounting worldwide about producing more rice per drop of water to feed rapidly growing populations, in semi-arid and arid conditions where rainfalls have failed to fulfill crop water requirement
The current study aims to evaluate supplemental irrigation for determining a suitable water depth that may improve water use efficiency through the Saturated soil irrigation (SSI) technique, which in turn will increase water productivity and farming output in dry climate conditions
Water stress at the early vegetative stage decreased growth parameters at panicle initiation, but recovery was observed at harvest depending on the severity of stress

Summary

Introduction

Concerns are mounting worldwide about producing more rice per drop of water to feed rapidly growing populations, in semi-arid and arid conditions where rainfalls have failed to fulfill crop water requirement. Improving yield per unit of water is a key concern in the face of the combined impacts of a growing population and food demand [1,2], and these concerns are acute in rainfed agricultural systems, which often have lower productivity [3]. In countries located in these dry prone regions, like Burkina Faso, rainfed rice production is constrained by rainwater shortage, and complementary irrigation is crucial to maintaining and/or increasing yield and production to meet fast-growing demand. The high fluctuation of rainfall in addition to several drought spells in rainy season lead to poor rice yields and low production growth, while an increase of 3% rice is required every year [4]. A key strategy is to minimize risk for dry spell induced crop failures, which requires an emphasis on supplemental irrigation [5]

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