Agrohydrological analysis of waterlogging impacts and mitigation in Ethiopia.

Waterlogging is a major yet understudied constraint to cropland productivity. Here, we apply an agrohydrological modeling framework to assess the climatology of waterlogging (1981-2010), its yield impacts on major grain crops, and the potential for mitigation at a 500m x 500m grid resolution across Ethiopia's rainfed agriculture (RFA) region. We estimate that areas within 39% of the grid cells in the RFA region are prone to waterlogging. Chickpea is the most sensitive crop, with average yield losses from 34% under low-severity to 97% under extreme-severity conditions, followed by wheat, barley, and faba bean (18-92% of yield loss). In contrast, maize and sorghum are generally tolerant except under extreme conditions. Our results also show considerable potential to reduce losses through soil drainage and use of tolerant crops. For instance, improved drainage could increase the current wheat yield on average by 57% under low waterlogging conditions. In flat areas where drainage is infeasible, productivity could be enhanced through using tolerant native crops and the expansion of rice production.