Moving toward the Biophysical Characterization of the Mangrove Swamp Rice Production System in Guinea Bissau: Exploring Tools to Improve Soil- and Water-Use Efficiencies

Abstract

The mangrove swamp rice production system (MSRPS) in West Africa faces significant challenges in soil, water, and salinity management, making rice production highly vulnerable to variations in the spatio-temporal distribution patterns of rainfall, which are exacerbated by climate change. This study’s results can provide the initial basis for co-developing strategies with farmers aiming to contribute to the biophysical characterization of the MSRPS, in particular: (i) estimate the water-harvesting efficiency (WLef) of the plots in the north and south of Guinea Bissau (GB); (ii) characterize the unevenness of the bottom of the plots, which leads to salinization spots; and (iii) create soil consistency maps to provide farmers with a tool to prioritize sites with optimal conditions for tillage. The research was conducted between 2021 and 2023 in the study site of Cafine-Cafal in the south and Elalab in the north of GB. Systematic soil sampling in a grid was designed to quantify the soil consistency and plot/ridge areas were determined. Linear models were developed to predict biophysical parameters (e.g., effective planting areas and water-logging depths) and geostatistics were used to create soil consistency maps for each study site. The results show precipitation water-harvesting efficiencies of 15% and 16% for the southern and northern regions, respectively. Furthermore, the plasticity limits of 18.6% for Elalab and 35.5% for Cafine-Cafal show the most appropriate times to start tillage in specific areas of the paddies. This study provides information on the efficient management of tillage and freshwater conservation, providing MSRPS farmers with useful tools to counteract the effects caused by salinity and rainfall variability.

The Mangrove Swamp Rice Production System of Guinea Bissau: Identification of the Main Constraints Associated with Soil Salinity and Rainfall Variability

“…Due to the specificity of the system at each location, there is therefore a research gap that needs to be overcome. With this in mind, studies were developed in Cafine-Cafal in the south and Elalab in the north of GB and presented in the companion article by Garbanzo et al [149].…”

“…Generating maps in this regard could provide farmers with valuable tools, allowing them to prioritize sites with optimal conditions for soil tillage. The companion article by Garbanzo et al [149] developed soil consistency maps with the aim of supporting farmers in decision making. • A lack of studies on tidal dynamics, for the creation of an early warning system, and on main dike management.…”

Analysis of the Rainfall Pattern and Rainfall Utilization Efficiency during the Growth Period of Paddy Rice

“…Specifically, the mathematical correlation between rainfall and rice production was established to propose appropriate planting strategies [19,20]. Recently, Garbanzo et al investigated the primary constraints associated with soil salinity and rainfall variability, proposing the Mangrove Swamp Rice Production System as a solution for rice farmers to mitigate the impacts caused by salinity and rainfall fluctuations [21,22]. Other scholars place greater emphasis on the impact of rainfall characteristics during specific rice growth periods on rice cultivation [23][24][25].…”