Irrigation Demand of Agriculture in Hesse

Background and Objective

The climate change is causing the average temperatures to rise and changes in the precipitation. Germany has experienced repeated droughts in the recent past. Climate forecasts indicate that in the future plants will more often not have enough water available during the growing season. With increasing water scarcity, the irrigation of agricultural cultures is becoming more important. In addition to the irrigation demand and the water supply, the profitability, the so-called economic efficiency of irrigation, also plays a role. 
The aim of the project is to determine the current status of agricultural irrigation for Hesse and the focus regions Hessisches Ried and Untermainebene as well as to estimate the future development of irrigation. The focus is on economic efficiency of irrigation and the analysis of strategies to assure the water availability. 

Target Group

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

Approach

The project is built on the previous studies of the Institute of Rural Studies of the Thuenen Institute and is structured in the following work packages: 

1. Analysis of the state of research and status quo of irrigation in Hesse
2. Extension of the existing model (for the state Bavaria) for the estimation the current and future regional irrigation demand by the component “water demand for frost protection irrigation” and application of the model
3. Analysis of strategies to assure the water availability for agriculture under consideration of technology, alternative water resources and organisational structures
4. Analysis of measures and instruments as well as existing funding opportunities with regard to the sustainable assurance of water availability
5. Extension of the model by the economic efficiency of irrigation (for selected cultures)
6. Scenario-based analysis of climate change-related regional adaption strategies for irrigated agriculture

Data and Methods

Spatial data on a daily basis is used to model the regional irrigation demand. These include climatic parameters like temperature and precipitation, land use and soil data as well as information regarding the phenology. Climate projection data of the RCP-scenario 8.5 of the German Weather Service is used to determine future developments. In addition, data on prices, yields and costs of irrigation are included for the irrigation economic efficiency. Groundwater recharge data is available from the Hessian Agency for Nature Conservation, Environment and Geology for the assessment of water supply.

Our Research Questions

• What is the current state of irrigation in Hesse?
• What was the regional irrigation demand of agriculture in Hesse for the ex-post period 1991-2020?
• How will the regional irrigation demand in Hesse develop until 2050?
• How can the irrigation economic efficiency be represented in the model and how will it change?
• What potential do alternative water resources offer for assuring resource availability for agricultural irrigation?
• What instruments and measures are available to assure water availability for agricultural irrigation exists and what funding opportunities exist?
• What are the potential impacts of agricultural adaption strategies on regional irrigation demands?

Results

This study estimates an increase in irrigation demands for agriculture and horticulture across Hesse of around +40% in the near future and a doubling in the distant future. The regional resolution of the results additionally indicates that irrigation demand could increase by a factor of 3-4 in some regions, particularly in the intensive vegetable and special crop areas of southern Hesse.

Anti-frost irrigation requires an average of 44 mm of water in Hesse, with early potatoes in particular having high demands. In the future, anti-frost irrigation is unlikely to play a significant role in Hesse: Due to the reduced risk of late frost, irrigation demand decreases by 94% in the long term compared to the reference period.

The economic efficiency for irrigation varies greatly between crops. While irrigation of vegetable crops and potatoes has proven to be economically viable over the years and in many regions, irrigation of cereals is generally unprofitable even when irrigation infrastructure is already in place. Overall, however, the economic efficiency of irrigation depends heavily on product prices and irrigation infrastructure.

With regard to possible adaptation strategies, however, further research is needed: although both crop rotations and irrigation management can be optimized in terms of more efficient use of water resources, further research is needed to develop comprehensive adaptation strategies and assess their effectiveness.