Assessing the Water Footprint of Irrigated Rice Production for Doho Rice Irrigation Scheme, Butaleja District, Uganda

Abstract

Water footprint assessment addresses the issues of freshwater scarcity and pollution which is limited to considering human activities that impact the quantity or quality of freshwater within a catchment. Water footprint” is an indicator of water use in relation to crop yield. It generally breaks down three components depending on water resources i.e. green, blue, grey water. The water footprint was determined using the climatic data of Mbale meteorological station (2002 to 2018). This study quantified the green, blue and grey water footprints of rice production for Doho Rice Irrigation Scheme found in Butaleja district in Eastern Uganda. Aqua crop model was used for simulating the crop water use and the yield which takes into account the daily soil water balance and climatic conditions. In addition, the water pollution associated with the use of nitrogen fertilizer in rice production is estimated. The study included two growing seasons of rice. The green water footprint was 1078 m3/ton and 𝟗𝟐𝟐.𝟓𝟕 m3/ton for the first and second season respectively. The blue water footprint was 141 m3/ton and 4812.16 m3/ton for the first and second season respectively. The grey water footprint was 129.87 m3/ ton and 𝟏𝟒𝟑.𝟑𝟗 m3/ton for the first and second season respectively. Deficit irrigation was considered majorly to policy makers in formulating water management strategies to reduce water footprint. Hence, these results are useful for paddy rice water management, specifically establishment of water saving policy.