Simulating agricultural water management strategies using an integrated surface subsurface hydrological model under future climatic extremes

Farmers face increasingly more uncertainty with regards to crop production of due to a changing climate. Temperature and precipitation patterns change, with prolonged periods of heats and droughts. This affects the crop growth season in terms of overall duration and increases the uncertainty of the crop growth conditions. Especially crop water availability is of importance to generate a good yield. Various management strategies can help to manage the water availability, such as drainage, irrigation infrastructures or a combination of both. Within the EU FARMWISE project, various water management strategies are evaluated that could help farmers mitigate future extreme weather conditions. The goal is to determine how various irrigation strategies perform under future climatic conditions.The management strategies under investigation are traditional sprinkler irrigation, subirrigation and a combination of controlled subirrigation with tile drainage. Utilising HydroGeoSphere (HGS), a 3D physics-based integrated surface-subsurface model was setup of an experimental field in the Netherlands. At the field site, an irrigation system, comprising of a controlled drainage with subirrigation is being monitored. The HGS model was calibrated using the field data to simulate the natural groundwater fluctuations, as well as the controlled drainage and subirrigation.To determine the effectiveness of the water management scenarios under various climatic scenarios, the water management scenarios were implemented into the calibrated model. The hydraulic head response and soil moisture content were the parameters of interest. To represent the future climate scenarios, precipitation and evapotranspiration from the SSP1-2.6, SSP2-4.5 and SSP5-8.5 scenarios over three time horizons were used. All model results in terms of hydraulic head and soil moisture response are currently being analysed to determine the effectiveness of the various management strategies under different climates.