Analysis of the impacts of irrigation practices and climate change on water availability for rice production: A case in Uganda

抄録

Worldwide, climate change is negatively impacting water resources and rice production. Rice crop in Uganda is grown on large and small-scale irrigation schemes with mainly traditional flooding, which overuses water compared to other irrigation practices. Additionally, rice production generally requires a lot of water during cultivation periods since its yield is strongly affected by water availability. The climate impacts on rice production range from unpredictable rainfall patterns, floods, landslides, to high temperature, which affects rice’s reproductive and development stages, thereby causing a decrease in plant height and root elongation. This study aims to analyze the climate change impacts more so temperature and precipitation on water availability and the application of water productivity open access remotely data (WaPOR data) to estimate the reference crop requirements (ETo). Long-term smoothed annual rainfall and precipitation data were downloaded from the climate knowledge portal. The ETo from 2010-2020 was calculated using the modified ETlook-WaPOR model. The results indicate that average temperatures have increased by 1.3°C since the 1960s. The western part of the country is warming faster than other regions with warming rate of 0.56°C/decade between 1950-2018. This will significantly affect water availability. The estimated ETo is found highest from December to march in all regions. Therefore, this study recommends: 1) improvement on the water storage, 2) promotion of water-use efficient techniques such as the Alternate Wetting and Drying technique for paddy, and drip irrigation for upland rice cultivation with farmer-led irrigation approach, 3) financing and promotion of in-situ weather, soil, water, and crop monitoring, and 4) Conduct training and knowledge transfer organic fertilizer production for farmers.