The fourthBHSSConference and Bulgarian chapter of IHSS with international participation was held on 8-10 September, 2016, in Sofia. More than 50 participants from Bulgaria, Greece, Malta and Russia took part in it, with 26 papers, 30 presentations and 23 posters, grouped around following main topics:
Organic carbon in soils and its contribution to mitigating the effects of climate change;
Characteristics and functions of humic substances;
Method of research, evaluation, and increase of the soil OM;
Application of humic and humic-like products in agriculture and industry.
During the 4th Conference papers concerning chemical hallmarks of black carbon dressed soils were presented (Tsolova et al., 2016a; 2016b). Overviews on the methods of research on evaluation and increase of the soil OM, utilization of composts in agriculture and its role for decreasing of heavy metals to vegetables were presented (Angelova et al., 2016; Babrikova et al., 2016; Popova et al., 2016; Stefanova et al., 2016).
From agronomical point of view during the 4th Conference an interesting comparative study on the influence of biological and conventional systems of agriculture on some characteristics of soil OM was presented (Nankova et al., 2016). The results provoked a thorough discussion between participants.
An interesting part of it was the topic 4: Application of humic and humic-like products in agriculture and industry. The main presentations covered topics in agriculture (Chakalov et al., 2016; Nankova et al., 2016; Pachev et al., 2016; Savov et al., 2016).
Proceedings of the 4th Conference, including 484 pages of reviewed papers under the edition of Filcheva, Stefanova and Ilieva, were prepared for the conference participants.
Conference scientific tour in the region of Sredna Gora Mountain was devoted to detailed description and discussions of three soil profiles and land reclamation of copper ore mine:
Profile 1 – is classified as Brown forest soil (Bulgarian classification); Dystric Cambisol (Humic, Siltic) (WRB, 2015)
Profile 3 – is shallow Brown forest soil, severely eroded with rock fragments; Eutric Sceletic Litic Leptosol (Humic) (WRB, 2015)
Land reclamation in Asarel-Medet copper ore mine with humic substances with tree species was demonstrated. Аsarel-Medet JSC is the first and the largest Bulgarian open pit mining company for copper and other ores processing with the practice of terrains remediation by humic substances application.