Assessing irrigation potential and its impact on crop productivity in the riparian zones of the Diamphwe River Basin, Malawi

Irrigation is vital for crop production, yet its potential is underutilised in many river basins. In Malawi, crop production is predominantly reliant on rainfall, making it vulnerable to climate change and natural disasters. The study evaluates the contribution of available irrigation resources (area) to crop production (yield) and assesses the extent of underutilisation. To achieve this, the irrigation potential (area) was mapped using Sentinel-2 land use and land cover analysis within 2 km buffer zones along the Diamphwe River. Additionally, 15 soil samples were analysed for HC, and government statistical data on maize yield and area were used to determine productivity, distinguishing the performance of rainfed and irrigated farming. Findings indicate that irrigated maize consistently outperformed rainfed maize in productivity, suggesting that harnessing irrigation could serve as a suitable alternative to the unreliable rainfed production in the basin, particularly within the 100–1000 m buffer zones that have greater irrigation potential. Kabwazi Extension Planning Area (EPA) accounted for 29 % and 33 % of the basin’s irrigable land in 2017 and 2024, respectively, due to its strategic positioning within the basin. The riparian zone displays medium hydraulic conductivity (HC), indicating suitable soils (luvisol) for infiltration, pollutant removal, and groundwater recharge, which are essential for sustaining river flow. Despite increased productivity, the impact of irrigation on maize remains minimal due to low participation by large-scale farmers and insufficient extension services, as evidenced by the underutilisation of potentially irrigable land (162.5 km 2 in 2017 and 145.4 km 2 in 2024). The study underscores the necessity for targeted policy interventions to optimise irrigation and enhance agricultural productivity and water resource management.