| dc.description.abstracteng | 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. | de |