• Deutsch
    • English
  • English 
    • Deutsch
    • English
  • Login
Item View 
  •   Home
  • Naturwissenschaften, Mathematik und Informatik
  • Fakultät für Forstwissenschaften und Waldökologie (inkl. GAUSS)
  • Item View
  •   Home
  • Naturwissenschaften, Mathematik und Informatik
  • Fakultät für Forstwissenschaften und Waldökologie (inkl. GAUSS)
  • Item View
JavaScript is disabled for your browser. Some features of this site may not work without it.

Quantifizierung der Feinwurzeln von Bäumen durch elektrische Verfahren

Quantification of fine roots of trees by electrical methods

by Andreas Koch
Doctoral thesis
Date of Examination:2015-04-15
Date of issue:2015-04-23
Advisor:Prof. Dr. Christian Ammer
Referee:Prof. Dr. Christian Ammer
Referee:Prof. Dr. Steffen Rust
crossref-logoPersistent Address: http://dx.doi.org/10.53846/goediss-5032

 

 

Files in this item

Name:Dissertation.pdf
Size:22.2Mb
Format:PDF
ViewOpen

The following license files are associated with this item:


Abstract

English

The quantification especially of fine roots of trees creates some difficulty because, contrary to the aboveground parts of the tree, roots are not readily visible. In recent years electrical methods have been developed for detecting the volume of roots without digging out and destroying the root system. Three methods were investigated in this thesis and the results of these methods were critically compared with those of other researchers. The grounding resistance measurement is a low-frequency method. This technique was tested in large field studies and was intended to find the optimal test assembly for the measurement and to investigate the major influencing factors. The earth impedance method is a further development of the grounding resistance measurement and also a low-frequency method. For the investigations for the earth impedance method, tests were performed in an electrolytic tray with imitations of a root and in some field experiments. The last of the three methods, the impedance spectroscopy, was tested in the laboratory with willow cuttings in a nutrient solution. The tests on the grounding resistance measurement showed that the main influential variable is the electrical resistance of phloem and xylem of the tree. Furthermore, temperature and soil moisture influence the earth ground resistance. The actual electrical resistance cannot be analyzed with this method separately from disturbances. Root imitations (copper cables or copper disks) in the electrolytic tray can only be identified if they are placed close to the liquid surface. The deeper the object lies in the solution, the more imprecise was the object displayed in the electric image. Further tests demonstrate that larger disks at a greater depth provide similar results to smaller discs at a shallower depth. The results cannot be interpreted clearly. The experiments with the impedance spectroscopy revealed the main factors which influence the impedance spectrum in differing large part. The main experiments showed good correlations between the raw data (real and imaginary part of the impedance) and the root length when using a quantile regression. Some models (equivalent circuits) were found which explain the measured data well. Especially the ohmic resistors and some capacities of the equivalent circuits correlate with the root length. These results differ from those of relevant publications. In summary, it can be determined that it is not possible to quantify the root system using low-frequency measurements. Further experiments in impedance spectroscopy are needed especially in respect to the marginal conditions. The present work can be seen as a first step towards a methodical foundation.
Keywords: impedance; grounding resistance; impedance spectroscopy; earth impedance method; root; fine roots
Schlagwörter: Impedanz; Erdungswiderstand; Bodenwiderstandsmethode; Impedanzspektroskopie; Wurzel; Feinwurzeln
 

Statistik

Publish here

Browse

All of eDissFaculties & ProgramsIssue DateAuthorAdvisor & RefereeAdvisorRefereeTitlesTypeThis FacultyIssue DateAuthorAdvisor & RefereeAdvisorRefereeTitlesType

Help & Info

Publishing on eDissPDF GuideTerms of ContractFAQ

Contact Us | Impressum | Cookie Consents | Data Protection Information
eDiss Office - SUB Göttingen (Central Library)
Platz der Göttinger Sieben 1
Mo - Fr 10:00 – 12:00 h


Tel.: +49 (0)551 39-27809 (general inquiries)
Tel.: +49 (0)551 39-28655 (open access/parallel publications)
ediss_AT_sub.uni-goettingen.de
[Please replace "_AT_" with the "@" sign when using our email adresses.]
Göttingen State and University Library | Göttingen University
Medicine Library (Doctoral candidates of medicine only)
Robert-Koch-Str. 40
Mon – Fri 8:00 – 24:00 h
Sat - Sun 8:00 – 22:00 h
Holidays 10:00 – 20:00 h
Tel.: +49 551 39-8395 (general inquiries)
Tel.: +49 (0)551 39-28655 (open access/parallel publications)
bbmed_AT_sub.uni-goettingen.de
[Please replace "_AT_" with the "@" sign when using our email adresses.]