Abstract:
Achieving rice self-sufficiency in West Africa will require an expansion of the irrigated rice area under water-scarce
conditions. However, little is known about how much area can be irrigated and where and when water-saving practices
could be used. The objective of this study was to assess potentially irrigable lands for irrigated rice cultivation under
water-saving technology in Burkina Faso. A two-step, spatially explicit approach was developed and implemented.
Firstly, machine learning models, namely Random Forest (RF) and Maximum Entropy (MaxEnt) were deployed in
ecological niche modeling (ENM) approach to assess the land suitability for irrigated rice cultivation. Spatial datasets
on topography, soil characteristics, climate parameters, land use, and water were used along with the current
distribution of irrigated rice locations in Burkina Faso to drive ENMs. Secondly, the climatic suitability for alternate
wetting and drying (AWD), an irrigation management method for saving water in rice cultivation in irrigated systems,
was assessed by using a simple water balance model for the two main growing seasons (February to June and July to
November) on a dekadal time scale. The evaluation metrics of the ENMs such as the area under the curve and
percentage correctly classified showed values higher than 80% for both RF and MaxEnt. The top four predictors of
land suitability for irrigated rice cultivation were exchangeable sodium percentage, exchangeable potassium, depth to
the groundwater table, and distance to stream networks and rivers. Potentially suitable lands for rice cultivation in
Burkina Faso were estimated at 21.1 x 105 ha. The whole dry season was found suitable for AWD implementation
against 25–100% of the wet season. Soil percolation was the main driver of the variation in irrigated land suitability
for AWD in the wet season. The integrated modeling and water balance assessment approach used in this study can
be applied to other West African countries to guide investment in irrigated rice area expansion while adapting to
climate change.
