RESUMEN
The challenge to sustainably intensify agricultural production in farming systems in face of the increasing variability in regional water resources requires concerted action from many stakeholders, locally, regionally and globally. Models, such as the AgroHyd Farmmodel presented here, can provide information on how farm management decisions affect local water resources at various scales for use in multiple assessment frameworks. It is a stand-alone web-based software that connects agricultural and water-related systems, including all water flows related to farming systems. Results from a case study of the production of 12 crops with rainfed and supplemental irrigation on a farm in northeastern Germany are described here. Indicators that relate the water use to plant production on the farm such as water intensity or water productivity are compared in detail for three consecutive years with greatly varying annual rainfall amounts (from 373 to 790â¯mm) to highlight the effect of local variability on water flows and indicator values. The discussion illustrates how information on the effect of management decisions, such as crop type, seeding date, crop rotation, cultivation and irrigation on water use can be processed into indicators to help farmers make more effective decisions.