Assessing Suitability of Irrigation Scheduling Decision Support Systems for Lowland Rice Farmers in Sub-Saharan Africa—A Review

Abstract

Irrigation in lowland rice production systems in Sub-Saharan Africa (SSA) is mainly based on traditional surface irrigation methods with continuous flooding practices. This irrigation method ends up using a lot more water that would have otherwise been used to open more land and be used in other water-requiring sectors. Various studies suggest Alternate Wetting and Drying (AWD) as an alternative practice for water management that reduces water use without significantly affecting yield. However, this practice has not been well adopted by the farmers despite its significant benefits of reduced total water use. Improving the adoption of AWD using irrigation Decision Support Systems (DSSs) helps the farmer on two fronts; to know "how much water to apply" and "when to irrigate", which is very critical in maximizing productivity. This paper reviews the applicability of DSSs using AWD in lowland rice production systems in Sub-Saharan Africa.

The Effects of Heavy Metal Pollution on Soil Nitrogen Transformation and Rice Volatile Organic Compounds under Different Water Management Practices

“… [ 70 ] Sprinkler irrigation approach for rice cultivation. [ 75 ] 2 Alternate wetting and drying (AWD) [ 12 , 76 ] Soil water potential (SWP) [ 38 , 77 ] Mulching cultivation without flooding [ 78 , 79 ] Aerobic rice system [ 48 ] Optimal irrigation regimen (OIR) [ 75 ] Saturated soil culture (SSC) [ 80 ] Field water level (FWL) [ 75 ] Intermittent drainage (ID) [ 81 ] Leaching and flushing methods (LFM) …”

Water Management for Sustainable Irrigation in Rice (Oryza sativa L.) Production: A Review

“…Although experiments on rice production under micro-irrigation systems (drip irrigation and sprinkler systems) are promising, traditional surface irrigation with continuous flooding practices and significant water consumption remains widely dominant in rice culti-vation for a number of reasons [121][122][123]. First, rice cultivation under surface irrigation is an ancestral practice and abandonment of this practice is constrained by socio-psychological barriers [124].…”

“…According to research [126][127][128][129][130], there are multiple water-saving technologies, including alternate wetting and drying (AWD), soil water potential (SWP), non-flooded mulching cultivation, aerobic rice system (ARS), efficient irrigation regime (EIR), saturated soil culture (SSC), field water level (FWL), intermittent drainage (ID), leaching and flushing methods (LFM), conventional flooding-midseason drainage-flooding irrigation (FDF), etc. The most popular water-saving technologies developed for rice production systems is the alternate wetting and drying (AWD) [121,123]. Islam et al [121] reported that, according to several authors, AWD entails intermittent irrigation events with intervals of non-flooding, wherein the water level drops below the soil surface between each irrigation, and this saves irrigation water by a range of 7-33% without significant impact on yield compared to conventional flooding.…”

“…The three-year (1999-2001) study revealed that irrigation water input was 15-18% lower under alternate water distribution (AWD) than under continuous submergence, and water productivity was higher under alternate AWD. Despite AWD being the most promoted amongst all the water-saving technologies (WST) due to its economic viability and environmental friendliness, it is not extensively used, which is probably because of the complex interactions between agricultural and socioeconomic systems and the absence of institutional backing [123,125,127]. Hiya et al [48] and Massey et al [80] reported that intermittent flooding with a reasonable depth of water above ground level would be an alternative to improve water use efficiency in rice production.…”