Improving the water use efficiency of irrigated rice cultivation in Benin, West Africa

Sustaining, or even increasing yields while improving the Water use efficiency (WUE) of irrigated rice is vital to cope with both the increasing risks of water scarcity and the feeding of the growing population in sub-Saharan Africa This study aims to improve the WUE for irrigated rice cultivation in central Benin. A field experiment was established and measurements performed from November 2022 to March 2023 at Koussin lélé, Cove district, using a split-plot experimental design. The main plot was assigned to water management technologies that included continuous flooding and two thresholds of periodic drying irrigation to 15 cm and 25 cm soil depth. The subplot was assigned to the nitrogen fertilizer regime which includes 90 kg ha-1 (farmer’s practice) and 120 kg ha-1 (enhanced amount of fertilizer). Based on biweekly conducted manual closed chamber (A: 0.16m2; V:0.16m3) measurements of evapotranspiration (ET) and CO2 exchange (ecosystem respiration (Reco) and net ecosystem exchange (NEE)), the seasonal dynamics in WUE were assessed as canopy (cWUE) and ecosystem water use efficiency (eWUE), respectively. Canopy gas exchange measurements were performed using a novel, low-cost ET and CO2 flux logger system (Macagga et al. 2024; RelatedIdentifier TAB1). Measured CO2 and ET fluxes were calculated using a modular R script described in detail by Hoffmann et al. (2015; Reco/NEE; RelatedIdentifier TAB2) and Dahlmann et al. (2022; ET; RelatedIdentifier TAB3). In addition to cWUE and eWUE, the crop season WUE was calculated as grain (gWUE) and biomass water use efficiency (bWUE). Results showed that the maximum grain yield (6.19 Mg ha-1) was observed for the continuous flooding rice cultivation receiving 120 Kg N ha-1 even though it was only 6.9 % higher than the yield recorded for the periodic drying at -15cm. The cWUE and eWUE followed the same pattern but were generally higher for periodic drying at -15cm under N90 with 2.63 g C (Kg H2O)-1 d-1 and 1.25 g C (Kg H2O)-1 d-1 respectively. Furthermore, this particular treatment also recorded the highest values for all the cumulative WUE parameters. Our findings emphasize the adoption of the periodic drying irrigation regime with an application rate of N90 Kg. ha-1 for more sustainable irrigated rice production. This table contains the index of all tables forming this data collection.

Related datasets are listed in the metadata element 'Related Identifier'.
Dataset version 1.0