Quantification of Climate Change Impact on Regional Agricultural Irrigation and Groundwater Demand

Climate change is expected to impact agricultural production conditions and groundwater resources. The climate change impacts are expected to be of particular importance for the German region North Rhine-Westphalia. Due to a high population density and intensive partial irrigation of agricultural production, future resource conflicts for groundwater are expected. An integrated model framework consisting of climate, crop-soils and groundwater models represents the regional heterogeneous climatic, geographic and agronomic conditions. The integrated model framework simulates the irrigation demand and groundwater recharge. An ex-post comparison between the simulated reference period (1961 to 1990) and statistical data prove a good model validity. The climate change scenario for the future period 2051 to 2080 assumes decreasing precipitation and increasing transpiration. The simulated total irrigation demand increases by nearly 20 times compared to the reference period (1961 to 1990) and increases regionally to more than 40 mm/ha. Decreasing groundwater recharge results in a tenfold increased share of irrigation water from groundwater. This share accounts regionally for more than 30 %. The results indicate important impacts for both agricultural production and other groundwater users

Bewässerung in der Landwirtschaft. Tagungsband zur Fachtagung am 11./12.09.2017 in Suderburg

On September 11 and 12, 2017, a symposium on "Irrigation in agriculture", jointly organized by the Thünen Institute, the Julius-Kühn Institute and the University of Applied Sciences Ostfalia took place at the Ostfalia University of Applied Sciences, Campus Suderburg. For this purpose, experts from the field of irrigation were invited to give current assessments on the development of irrigation needs and the irrigation-worthiness of different crops at different locations in Ger-many as well as on the development of irrigation technology. The irrigation of crops in outdoor vegetables or special crops has long been a common practice. The profitability of irrigating agri-cultural crops in Germany has so far been limited to a few, dry locations. As a result of climate change, an increasing average annual temperature and changed precipitation patterns (in partic-ular lower rainfall at the beginning of the vegetation period in spring) have been observed in Germany for some years now. For the future, according to the results of climate models, a fur-ther increase in temperatures and further changes in the precipitation distribution such as a de-crease in the summer precipitation and an increase in winter precipitation are to be expected. The conference proceedings provide an overview of the latest research findings from the field of drought stress and discuss possible alternative sources for meeting the additional water require-ments of agricultural crops. Aspects of the landscape water balance and hydrological correlations in the agricultural landscape are addressed and solutions presented. Insights into possible con-flicts of water use and practical experience with the development of solutions are accompanied by the presentation of the legal framework for water use. The contributions are supplemented by reports of long-term irrigation field trials conducted by the LWK Lower Saxony. On the one hand, the experiments have shown that irrigation can increase the nutrient efficiency of crops and the quality of crops. On the other hand, the present state of the art of irrigation will be explained and limits and possibilities for increasing efficiency in the future will be presented. In order to in-crease the efficiency of irrigation, irrigation control is of great importance; its current status is presented and the trends for the future are shown. The profitability of investments in irrigation technology is presented in two contributions. Here, both the different techniques and their prof-itability in different crops are assessed economically. Possible developments of regional irrigation needs are exemplarily shown for the federal state of North Rhine-Westphalia. The conference proceedings conclude with a chapter on the overview of previous projects in the field of water management and on irrigation of agricultural land in view of future climate change in Germany