Innovative Approaches to the SDI (Subsurface Drip Irrigation) Principle

For a more sustainable use of water for agriculture in times of increasing droughts and worldwide water shortages effective irrigation systems become more important. Regarding the loss due to evaporation subsurface drip irrigation (SDI) is the most water saving irrigation system. In cooperation with the company hydrip GmbH an extremely water-saving irrigation system is prooved in this project. It consists of the combination of subsurface pipes with a water-holding soil amendment basing on clayminerals. Due to the emplacement of the amendment the water retention character of the soil shall be improved, especially in sandy soils. In the first part of the project, the optimal amount of the quite cost-intensive soil amendment has to be found out. Basing on soil-physical laboratory measurements with soil-amendment mixtures, simulations of the soil water balance with HYDRUS will be accomplished. A problem of subsurface drip irrigation system is, that plant roots grow into the pipes and even block them in search of water. Commonly, this problem was faced by the addition of Trifluralin-containing herbicides. Due to an EU-wide prohibition of this agent, alternatives have to be developed that inhibit the root ingrowth physically or chemically. Thus, a prototype of a new irrigation-pipe system will be tested, that should be able to inhibit the root ingrowth mechanically. In the following course of the project, plant grow experiments in the laboratory shall verify the results and prepare the field tests. After that, the operation of the optimized system is tested in the field. Therefore, a golf putting green and a new grape planting will be equipped with the irrigation system and will be observed for at least two vegetation periodes.