This title appears in the Scientific Report : 2013 

Non-invasive characterization of biochar using geoelectrical measurements – A laboratory study
Haegel, Franz-Hubert (Corresponding author)
Esser, Odilia / Borchard, Nils / Jablonowski, Nicolai David / Mukherjee, Santanu / Linden, Andreas / Zimmermann, Egon / Huisman, Johan Alexander / Vereecken, Harry
Zentralinstitut für Elektronik; ZEA-2
Pflanzenwissenschaften; IBG-2
Agrosphäre; IBG-3
International Conference Biochars, Composts, and Digestates., Bari (Italy), 2013-10-17 - 2013-10-20
Conference Presentation
Modelling and Monitoring Terrestrial Systems: Methods and Technologies
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Non-invasive characterization of biochar using geoelectrical measurements – A laboratory studyFranz-Hubert Haegel1, Odilia Esser1, Nils Borchard1, Nicolai D. Jablonowski2, Santanu Mukherjee1, Andreas Linden1, Egon Zimmermann3, Johan Alexander Huisman1, Harry Vereecken11 Forschungszentrum Jülich, Institut für Bio- und Geowissenschaften, IBG-3 Agrosphäre2 Forschungszentrum Jülich, Institut für Bio- und Geowissenschaften, IBG-2 Pflanzenwissenschaften3 Forschungszentrum Jülich, Zentralinstitut für Engineering, Elektronik und Analytik, ZEA-2 Systeme der ElektronikNon-invasive methods that allow the detection and the characterization of biochar on large scales are not available. Spectral induced polarization (SIP) is a promising technology to address this need. It has been used for ore prospection since about 100 years and in more recent years, it has also been applied to soil systems. SIP yields the complex electrical conductivity in the frequency range from about 1 mHz to about 10 kHz. The complex quantity comprises a real part due to electrolytic conductivity and an imaginary part due to polarization effects in the pore space. Since the polarizability of biochar is comparatively large because of its polyaromatic structure, the addition of biochars to soil yields increased values for the imaginary part of the electrical conductivity. The signal strength depends on the type and the amount of biochar. The frequency dependence of the imaginary part of the electrical conductivity is further influenced by the particle size distribution of the biochar. Measurements on biochar in soil and systematic investigations on model systems containing series of different biochars and active carbons will be presented. The results of the measurements in the laboratory show that SIP can be used to characterize biochar in soil and to monitor changes in biochar properties with time in addition to standard SIP characterization of ion concentration and water content. Although the current results were obtained in laboratory experiments, field imaging of SIP properties of areas up to several 100 square meters is possible with multi-electrode equipment.