To promote sustainable production and the multiple roles of paddy rice, it is essential to expand our understanding of the impacts of different management options, with particular emphasis on irrigation development. The impact of various management practices (supplementary irrigation during the rainy season, improved fertilization, cropping during the dry season and mulching practices) on irrigation water requirements, crop productivity and the multifunctional roles of irrigated paddy rice was evaluated in diverse agro-ecological zones of Zambia, by using the AquaCrop model. Irrigation development has been demonstrated to boost paddy rice production (by 8%) in the southern districts by providing supplementary irrigation (about 150 mm) during the rainy season. Additionally, supplementary irrigation during the rainy season can make improved fertilization more attractive, doubling the yield rise under rainfed conditions. The required irrigation development would also enable paddy rice cropping intensification by allowing for dry season sowing (with net irrigation requirements from 700 to 800 mm). Moreover, the associated straw production increase could also play an important role as mulch during the dry season, reducing the net irrigation requirements by 15%. These findings will enable policymakers to make informed decisions regarding investment strategies and policies.