Sustainable agricultural strategies to address limited freshwater availability and meet food demand in the Nile River Basin

Providing healthy food from a sustainable food system, while satisfying the demand of a growing population, is one of the major challenges of the century.  The limited agricultural land and water represent the main boundaries to meet the food demand of a growing population (Davis et al., 2014, 2017). Moreover, availability of natural freshwater is expected to furtherly decline in future due to climate change (Rodell et al., 2018) – especially in arid regions – and, thus, there is an urgent need to reshape the agricultural system to sustainably feed a global population approaching 9 billion people in the next century (Godfray et al., 2010).

Food security in the Nile Basin is strictly related to the availability of freshwater resources, which are increasingly threatened by climate change and future demographic trends. Currently, food production is insufficient to meet the population food demand, and all Nile countries are currently net food importers. Healthy food is also needed to address malnutrition within the poorest rural communities in the Nile countries. Countries in the Basin are highly affected by undernourishment - linked low dietary energy - iron-deficiency-induced anemia and diabetes. The agricultural sector is the largest consumer of the Nile waters and, thus, the state of the food system has profound implications for attaining water security in the Nile Basin (NBI, 2020).

In this study we suggest a sustainable agricultural strategy to enhance sustainable a food system within the Nile River Basin. We couple the WATNEEDS hydro-agrological (Chiarelli et al., 2020) model with a linear optimization algorithm to reshape the current cropland with the aim of producing more healthy food, with several benefits for the ecosystem (e.g., reduced irrigation water consumption) and human health. Cropland redistribution can be coupled with agricultural intensification and diet shift generating, at the meso-scale, benefits in terms of irrigation water savings and increase in food self-sufficiency. We first evaluated the amount of irrigation water and the crop production related to the current crop distribution and second, we identified potential differences in food production and water consumption between the current and optimized crop distributions. We use the WATNEEDS model to quantify spatially distributed crop water requirements, - namely blue and green water requirements - which are the volumes of water needed to compensate crop water losses through evapotranspiration. Our results show that crop redistribution increases food availability and, thus, the percentage of population sustained sustainably with the local agricultural production, reducing the pressure on the currently available renewable freshwater resources of the Nile.