Browsing by Subject "Fuzzy expert systems"

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Integrated technical approach for differentiated nitrogen application based on expert knowledge and multiple parameters
(2023) Heiß, Andreas; Griepentrog, Hans
Variable rate nitrogen (N) application is subject to spatio-temporal dynamics of multiple parameters and a high dependency on specific local conditions. Furthermore, existing algorithms are barely capable of considering agronomic expert knowledge and common application technology limits the precise in-field realization. This work approached the complexity of site-specific N management in terms of the decision making, as well as the technical and organizational realization in a systemic manner. A commercial real-time N-sensor system’s behavior was transferred into a fuzzy expert system and extended with soil information. The incorporation into a real-time control included also the spatial synchronization of dose rate determination and realization. A digital process chain to facilitate decision making, data management and execution in the field was conceptualized and evaluated with a prototypical implementation. The N-sensor’s algorithms were precisely imitated with a maximum percentage root mean square error of 0.14%, while the multi-parametric system has implied more robust decisions. In field tests, the real-time control has shown acceptable synchronization errors largely below 1 m and with medians in the range of 0.25 m under realistic conditions. The integrated system architecture has shown a high consistency in terms of straightforward and situative expert knowledge acquisition, as well as the suitability for different sensor and application technologies. The work represents a systemic approach for a derivation and employment of machine-readable algorithms from agronomic expert knowledge defining the cause-effect relationships for a site-specific N application. Its generic properties allow a supplementation by other models and can in turn strengthen them further.