Ausgabe zur AGRITECHNICA 2019

11 irrigation Reduzieren Sie Beschaffungsaufwände und optimieren Sie Materialflüsse und Lagerbestände. Senken Sie Montagezeiten und beugen Sie Montagefehlern vor. Mit STAUFF als Ihr leistungsfähiger Partner für Fluidtechnik-Komponenten, Systeme und Dienstleistungen mit Mehrwert aus einer Hand. Hydraulik- Leitungstechnik von Anschluss zu Anschluss Erfahren Sie mehr unter www.stauffline.com und auf der Agritechnica Halle 17 I Stand F41 vom 10. - 16. November 2019 in Hannover these devices. The trend in this development is shifting towards small-scale planning areas and therefore towards sub-area-spe- cific (precision) irrigation. However, spatially high-reso- lution, up-to-the-minute data regarding the crops' need for irrigation are required for this. The use of soil moisture sensors or the climatic water balance can be limited though, for example in the case of very heterogeneous soils and a very high number of sub-areas. Conversely, the deri- vation of irrigation requirements from image information enables a very high spatial resolution. Work is currently being undertaken on corresponding determination ap- proaches in many locations, and small-scale irrigation planning by means of satellite images will be possible in the longer-term. As the spatial resolution of satel- lite images is often still too low at present, drones are being used in current research to obtain the re- quired image information. Optimisation in irrigation technology It must be possible to implement small-scale irrigation planning through small-scale water output. Corresponding control systems with decentralised operation that can be used for this purpose are already available on the market. In stationary systems, these can be flexibly usable radio nodes that can simultaneously activate sensors (for example soil mois- ture) and actuators (for example. solenoid valves). Conversely, sub- area-specific irrigation in mobile systems is implemented using individually actuated solenoid valves that are installed upstream of the spray nozzles or small sprinklers and are activated de- pending on their current position. A clear trend towards the reduc- tion of operating water pressures, and thus the reduction of energy requirements during irrigation, can also be seen. In drip irrigation, pressure-compensating drippers, that implement identical flow rates with different water pressures, ensure spatially homogeneous water output. Modern pressure- compensating drippers can be operated with pressures as low as 0.4 bar. Similar progress has been achieved in spray nozzles for use in mobile irrigation systems. For instance, nozzles that can also be used with water pressures as low as about 0.4 bar are already available. Lower water pressures when using spray nozzles necessitate smaller spaces between the spray nozzles on mobile irrigation systems. In turn, water efficiency and distri- bution accuracy can be further im- proved thanks to this close nozzle arrangement. This is particularly achieved through shorter spray- ing heights and distances, but also by means of larger droplets, resulting in less water loss due to wind drift and evaporation. Low energy precision applica- tion (LEPA) aims to provide fun- damental improvement of water efficiency in mobile irrigation by means of spatially limited water output with low water pressures. The objective of irrigation in this case is no longer the output of water across the entire crop, but directly onto the soil between the plants. In technical terms, this can be achieved through very low- hanging nozzles with short spray- ing distances and low water pres- sures. The resultingly optimised water efficiency arises due first to the avoidance of interception, that is the trapping and evaporation of water on the leaves. Second, wind drift is negligible and evaporation losses across the surface of the soil are comparatively lower. In summary, it can be stated that the developments and innova- tions in irrigation take account of the present and future problems concerning resource wastage and water shortage. They are also specifically supported by subsidy programmes.  Text & Image: DLG Service GmbH Eschborner Landstraße 122 D-60489 Frankfurt am Main