Transfer of Main and Trace Elements from Soil to Plant with an Emphasis on Trace Element Supply for Biogas Digestion Plants
by Wiebke Fahlbusch
Date of Examination:2018-07-05
Date of issue:2018-10-01
Advisor:Prof. Dr. Hans Ruppert
Referee:Prof. Dr. Hans Ruppert
Referee:Prof. Dr. Klaus Dittert
Files in this item
Name:Dissertation_Fahlbusch_2018.pdf
Size:18.0Mb
Format:PDF
Description:Dissertation
Name:Element_Data_W_Fahlbusch_2018.xlsx
Size:813.Kb
Format:VND.OPENXMLFORMATS-OFFICEDOCUMENT.SPREADSHEETML.SHEET
Description:Anhang
Name:App_plot_Standards.zip
Size:209.Kb
Format:OCTET-STREAM
Description:Anhang
Abstract
English
In this study trace element uptake by different plants and plant species on different soils was investigated. A special focus was on the uptake of the elements Co, Ni, Mn and Mo, as those were essential elements for biogas production. The research project, in which this study was situated, aimed to provide enough trace elements (TE) by an addition of alternative energy crops as substrate for biogas digestion plants. Maize, which is used as the main (plant) substrate had the disadvantage of a very low trace element content of Co and Ni in particular. This study contributed to the assessment of the most important factors for trace element mobility leading to recommendations for farmers to increase trace element delivery to biogas plants with the plant substrate. Furthermore the aspects: soil parameters (pH, soil type, element concentrations, potentially available elements), the influence of the plant species on element uptake, and the transfer factor (TF) of elements from soil to plant were covered. In this project twelve different variants (plant species, cropping systems) were tested in two main field trials, on a very good quality soil (Garte Nord, Reinshof) and an intermediate quality soil (Sömmerling, Uslar). The sample set was extended with additional plant samples from other projects. A small scale field trial and pot experiments were performed to test the mobility of trace elements on different soil properties. Acidic soil pH conditions led to high mobilities of Cd, Co, Ni, Mn or La, as seen in soil extractions and plant element contents. Plants grown in soil with greater total trace element concentration originating from basalt weathering showed increased content in some plant species as well, for example in Fabaceae (legume) plants. Other plant species (Poaceae; maize, cereals, ryegrass) were almost unaffected. A great influence was detected by the plant species, the different plant structures and uptake mechanisms probably led to a distinct uptake pattern for main and TE. These patterns were visible in the concentration levels, in multivariate analysis on the data after a Principal Component Analysis and in different TF. Greatest concentrations of Co and Ni were found in Fabaceae plants (winter and summer faba bean). For Mn and Mo, ryegrass samples showed the largest enrichment. With the means of soil extractions (mainly ammonium nitrate) and total soil element concentrations it was shown, that correlation trends of plant and soil concentrations were detected mostly for Co and Ni and the plant species winter faba bean and hairy vetch. However, these trends cannot be used for a prediction of the concentration in the plants, because of too high variability within one plant species (namely ryegrass) leading to low correlation coefficients. The plant concentrations were combined with dry mass (DM) yield to obtain element extraction from the field in g/ha, or the delivery to biogas plants (in plant silage). A good annual DM yield and a greater amount of TE can be realized with faba bean (mono or intercropped with triticale) succeeded by maize, or with main crop ryegrass.
Keywords: Energy crops; Trace elements; Cobalt; Nickel; Biogas production; Soil-plant transfer