Water productivity and water requirements in food production : examples from Ethiopia, Tanzania and Burkina Faso

Sammanfattning: The majority of agricultural croplands globally is rainfed. This calls for agricultural practices which promote as productive use of precipitation water as possible, to maintain sufficient crop growth for food production. Global population is estimat-ed to increase to 9.3 billion by 2050 leading to a projected increase in food demand of 60 % from today. This, together with climate change which is projected to entail uneven precipitation patterns, will put further pressure on water resources and de-mands more thoughtful water management to maintain and improve yields. Additionally, another global issue is malnutrition, a consequence of uneven food distribution, food availability and food accessibility. Nutritive deficiencies together with global population increase and changes in dietary patterns call for increased food production both in biomass yield and crop qualities considering nutrition. To meet these demands with limited water resources, food production requires systems with high water productivity (WP) to gain most quality output as possible in terms of yield, to water input. In this case the input is seen as evapotranspiration. The aim with this study was to elucidate the concept Dietary Water Productivity (WPdiet) in Sub-Saharan Africa (SSA) for diets differentiated by income levels in Ethiopia, Tanzania, and Burkina Faso. The study included a review of WP and calculations of energy and nutritive output related to evapotranspiration in crop production and diet composition. This was put in relation to national available water resources in respective country. This study shows: 1. A data gap of values of WP in SSA for main crops included in diets. 2. Country specific differences in water productivity of energy and nutrition out-come depending on food composition and total food consumption. 3. Insecurities in estimated supplies of national precipitation and liquid water re-sources to sustain future national food production in Ethiopia, Tanzania, and Burkina Faso.