Land degradation and food security: water erosion impacts and adaptation options

Land degradation is estimated to affect more than a quarter of the global land area. Together with climate change, land degradation is expected to increase the risk of food security in many regions of the world. Land degradation reduces the quality of the soil, which declines crop yields, production volumes and farming incomes. We use the global computable general equilibrium model ENGAGE to assess the potential economic impacts of land degradation across countries and across sectors. The ENGAGE model has been specially designed to assess agricultural and land use policies. It includes agro-ecological zones, first generation biofuels and irrigation. The relationship between soil nutrients losses and crop yields is modelled at the global scale by the biophysical crop model EPIC-IIASA. The results show that if the natural nutrients in the soil are not replaced with fertilisers or natural sources crop yields decline. This depletion of nutrients leads to nutrient mining compromising the long-term sustainability of agricultural systems and declining the economic benefits. Economic losses due to land degradation are considerable in developing countries, thus integrating to the policy mix adaptation strategies tackling land degradation is crucial for regional and global food security.