Agricultural Investigation of soils using mobile electrodes
Motivation
Abb. 1: Rollelektroden des ATB Potsdam-Bornim
Precision farming and the increased importance requires large-scaled soil information. Main aim is to describe the clay content, water retention, compaction and hydraulic permittivity of the first two meters. For this a layered approach should be used to derive a three-dimensional subsurface model. The electric conductivity (EC) is a key parameter for different properties and can be mapped very fast. However, existing instruments based on EM induction can only yield one or two mean values per measuring point. We present an approach of using rolling electrodes for a continuous resistivity sounding.
Data processing
The measured raw data have a minor quality due to the moving electrodes and have thus to be processed. With the same method as used for the underwater resistivity surveys the error-weighted time series for each channel are fitted by a harmonic analysis and interpolated onto a spatially equidistant grid. Figures 2 and 3 show the raw data and their processed results.
Fig. 2: Raw data
Fig. 3: Processed data
Inversion
The individual soundings are interpreted by a 1d sounding. The layer thicknesses are held constant (0-0.3m-0.7m-1.2m-1.8m-). Finally the results are associated to spatial positions and we derive a large-scale layered model of the soil. Fig. 4 shows such a result.
Fig. 4: Driven route and conductivity distribution for the 5 inverted layers
Products & publications
Contact
+49 (0)511 643-3494
Members
Wolfgang Südekum
Partner
Horst Domsch & Robin Gebbers, Leibniz Institute for Agricultural Engineering Potsdam-Bornim