Model and Growth Stage Based Variability of the Irrigation Demand of Onion Crops with Predicted Climate Change

Predicted climate change will affect agricultural water resources. Particularly vegetable crops will be concerned due to high water demand and high vulnerability to water scarcity. Present vegetable production already requires irrigation water. To assess future irrigation demand, the impact of climate change needs to be revealed region-and crop-specifically. For robust predictions, a wide range of scenarios has to be simulated using different climate models. The aim of this study is to identify the climate change impact on water availability, precipitation-free periods and irrigation demand of onion crops cultivated in a German model region. Focus is on crop-specific climatic water balance, considering soil characteristics and temperature-driven plant growth. Simulated climate parameters vary between four climate models. However, in all scenarios climate parameters indicate an increasing water demand until 2100. While amount of irrigation water will not increase tremendously, occurrence and duration of dry periods will require efficient irrigation infrastructure and management.