Affiliation(s)
1. Department of Soil Genesis, Geography and Classification, Nikola Poushkarov Institute of Soil Science, Agrotechnology and Plant Protection, Sofia 1080, Bulgaria
2. Department Common Agriculture, University of Forestry, Sofia 1718, Bulgaria
3. Balkan Plant Science Ltd. Co., Sofia 1000, Bulgaria
ABSTRACT
The aim of the study was to characterize
humus system of natural and artificial products.
Humus systems from leonardite, lignite biotransformed with Trichoderma sp. (Plantagra), plant materials after pyrolisis
(charcoal) and composts are compared. Humus systems are characterized by
Kononova-Belchikova’s method, and heavy metals content was
measured by atomic absorption spectroscopy (AAS). Humic acids
from the International Humic Substances Society (IHSS) collection are the standards for humus
substances quality of compared products. Data obtained for leonardite indicate
that the studied substances
from factory, Izmir, Turkey contain humic acids over 94%. Compared to the
standard, heavy metals content
in these materials demonstrate high amounts. Organic carbon
content in the composts is very low compared to the leonardite materials and IHSS
collection, where the heavy metals content is lower. Biotransformed lignite is
characterized with lower content of organic carbon, but humic acids are with
high degree of humification. Results obtained show that the fourth studied
humus systems may be used in agriculture on base of the high humic acids
content. It is recommended to measure heavy metals content before applying the materials in
agriculture.
KEYWORDS
Compost, humic acid,
leonardite, lignite, sewage sludge, Trichoderma harzianum, Trichoderma
viride.
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References