Bożena Smreczak, Jan Jadczyszyn and Cezary Kabała
The agricultural value of rendzina soils depends on many factors, including type of parent rock, texture of arable layer, admixture of post-glacial materials and occurrence of coarse fragments. Over 97% of rendzinas in Poland are arable soils, and less than 3% are under permanent meadows and permanent pastures. Rendzinas are soil of high production potential for agriculture. Almost 75% of them were included in the wheat complexes (from 1 to 3) while about 10% are weak and very weak rye soils (complex 6 and 7) in Polish land suitability system. Groups of rendzinas identified for agricultural purposes and the principles of their identification were established on 1950s and 1960s when bonitation maps and soil-agricultural maps were prepared. These principles have not changed so far, therefore the purpose of the work was to describe the divisions of these soils and the characteristics of their properties on the example of arable soils based on the available data.
Krzysztof Gondek, Monika Mierzwa-Hersztek, Bożena Smreczak, Agnieszka Baran, Michał Kopeć, Tomasz Mróz, Paweł Janowski, Tomasz Bajda and Anna Tomczyk
The aim of this research was to determine the effect of thermal conversion temperature and plant material addition to sewage sludge on the PAHs content and the activity of selected γ-radionuclides in biochars, and to conduct an ecotoxicological assessment. The pyrolysis of the mixtures of sewage sludge and plant materials at 300°C and such temperature caused an increase in the contents of 2- and 3-ring hydrocarbons. During the pyrolysis of organic materials at 600°C, the amount of the following compounds was reduced in biochars: benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3c,d]pyrene, dibenzo[a,h]anthracene, and benzo[g,h,i]perylene. Among γ-radioisotopes of the elements, natural radiogenic isotopes were dominant. 137Cs was the only artificial radioactive isotope. The pyrolysis of the mixtures of municipal sewage sludge and plant materials revealed that isotope 40K had the highest radioactive activity. In the case of other analysed nuclides, activities of 212Pb, 214Pb, 214Bi, and 137Cs were determined after the sample pyrolysis. The extracts from the mixtures of sewage sludge and plant materials were non-toxic to Vibrio fischeri.