Biological characteristics of composts and biochar as determined by plant response analysis

The evaluation of quality standards for compost and growing media as well as their compounds are of relevant interest for manufacturers and national authorities to obtain a consistent high quality of the material in long term finally. A diversity of different measuring methods exists to identify primarily chemical and physical properties with little regard to biological indicators. Therefore on the one hand this study focuses to connect especially chemical properties e.g., pH, EC or plant available N of different materials such as compost and biochar with the results of biological indicator of plant response analysis e.g., fresh plant biomass or germination rate, on the other hand to assess the suitability of the used materials for further use in agriculture and horticulture. The plant response analysis were in fact the pot growth test using cress, pot grow test with Chinese cabbage and the petri dish test using cress. A positive relation was found between chemical and biological indicators. The evaluation revealed that comparability between both pot growth tests (cress and Chinese cabbage) can be assumed. The petri test using cress seemed to be an important additional instrument to point out phytotoxic impacts. These findings provide stakeholders practical experience to draw conclusions about the interactions between different materials.