LAWAMAD – Agricultural water management in Germany (Subproject C)

Background and Objective

The joint project LAWAMADaims to analyse the options for improved water management in German agricultural landscapes with the objective of increasing water availability for irrigation. In the Subproject C, `Regionalized analyses of irrigation demand and irrigation economy efficiency in Germany under climate change´, the current irrigation situation will first be quantified.

With the parameter `irrigation demand´, the potential additional water requirements for the most important arable and vegetable crops, as well as specialized crops, will be determined. The amount of supplemental water is influenced by climatic, soil physical and crop-specific parameters, and is always used to maintain optimal plant growing conditions. Irrigation demand is used as an indirect parameter to derive a statement on the quantitative share of agriculture in the total water consumption.

In addition, economic aspects of irrigation are included and quantified in the project. For this purpose, the parameter irrigation economy efficiency is examined. A crop is worthy of irrigation if the additional costs of irrigation can be compensated by the additional yield ensured by the optimal plant water supply.

Thus, Subproject C is the first national quantification of irrigation and its economic efficiency as well as regional differences under present and future climate conditions on a national scale.

Target Group

Policymakers, agricultural producers, advisors, regional water associations, chambers of agriculture, interested professionals and the general public

Approach

Subproject-C will be addressed in two work packages:

1. First, a model will be developed that can be used to quantify the regional irrigation demand for cropland at the community level for the entire area of Germany. Calculations are made for the current status. Then, regionalized climate projection data feeds the model to estimate future irrigation demand trends in the context of climate change.
2. Based on operational cost structures (purchase, water supply, yield, etc.), a model is developed to estimate the irrigation economy efficiency of selected crops. The model will be used to estimate the current situation as well as future changes.

Data and Methods

Both models are based on detailed and real time data of the agricultural crop distribution, climatic parameters and crop-specific attributes. The aim is to achieve an area-wide and regionally high-resolution view of the German agricultural irrigation system.

Our Research Questions

The research questions are:

• What are the current irrigation demands of different agricultural crops in Germany?
• How will the irrigation demand develop when regionalized climate projections are considered?
• What is the irrigation economy efficiency of different selected crops in Germany?
• How does the irrigation economy efficiency of crops develop with projected climatic changes in the future?

Preliminary Results

Results from previous studies for the German states of North Rhine-Westphalia and Bavaria have shown that the need for irrigation is particularly characterized by cultivation of vegetables and arable crops with an enhanced water requirement, such as potatoes or sugar beets. Due to the expected climate changes, the irrigation demand in typical irrigated regions will continue to increase and expand into regions where no irrigation has taken place so far.

The developed approaches will to be refined and implemented for the federal level. In addition to a spatially differentiated irrigation demand for Germany, findings on the economic impacts of climate change on selected crops are expected.