Rationale for agrotechnologies and farming systems in rice cultivation in the Republic of Ghana

Low rice yield, which, with a harvest frequency of 2 times a year, averages about 3 t/ha over two annual harvests, are a key constraint to achieving food security in Republic of Ghana. Average annual rice production is approximately 1 million tons, which accounts for only 40% of the country's domestic needs. This is due to a number of challenges, the main ones being water shortages, poor or absent rice cultivation practices, pests and diseases, and soil degradation. Addressing these challenges is a critical task for the country, as evidenced by government programs supporting the rice industry, such as the Feed Ghana Programme (FGP), the K-Rice Belt project (RiceSPIA), and the REWARD project. Therefore, the objective of our research was to identify new rice cultivation technologies by conducting a two-factor field trial in 2025. This trial examined two irrigation regimes – continuous inundation (CI) and alternate wetting-drying (AWD) – in combination with optimized nitrogen fertilization (N30-N150 kg/ha). The study was conducted in the Volta region, one of the 16 regions of the Republic of Ghana, located southeast of lake Volta. Based on the results, a universal optimal nitrogen dose of N120 kg/ha was determined for both irrigation regimes. It was found that the CI irrigation regime is the most productive but more water-intensive, while the AWD irrigation regime represents an effective resource-saving compromise that significantly increases crop yields and improves production sustainability. For large irrigation systems, modernization and implementation of the CI irrigation regime are recommended, while for most farms, the implementation of the AWD irrigation regime is strategically preferable as a technology adapted to water scarcity.