The fourth BHSS Conference 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:
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: