Assessing biochar quality by germination tests

Germination tests were performed in order to assess biochar quality. Biochars were obtained from corn stalk pellets using two pyrolysis reactors and five different combinations of residential time and temperature. The five biochars were employed at diverse concentrations to perform germination tests of garden cress (Lepidium sativum L.) and perennial ryegrass (Lolium perenne L.) in soil-less Petri dishes bioassay. In general, the higher is pyrolysis temperature the higher is carbonization rate; the pH values range from 8 to 11 while EC values range from 16,2 to 4860 microS.cm-1, both rising with increasing biochars in the suspension. Concerning germination tests, at lower concentrations no significant differences arise from the thesis otherwise, the highest concentration seems to determine a decrease in the number of germinated seeds and a weak grow of sprouts.