**4. Conclusions**

The present study shows that tobacco biomass and energy yields can match other commercial energy crops in Poland. Its energy yields varied between 160 and 273 GJ ha−<sup>1</sup> yr<sup>−</sup>1, which is comparable to poplar and willow energy yields. Tobacco, however, could be a valuable biomass energy crop, especially when cultivated deliberately to obtain biomass. This study showed that tobacco can be cultivated on soils of poor quality and high yields can be still maintained. The tested tobacco (harvested in October) seemed to be a rather poor source of substrate for biogas production, which was probably due to harvesting time and the high lignification rate of tobacco tissues. Yield of methane per hectare of tobacco was 2847 Nm3 ha−<sup>1</sup> yr<sup>−</sup>1.

**Author Contributions:** Conceptualization, A.K.B.; methodology, A.K.B. and M.M.; software, A.K.B.; investigation, A.K.B.; resources, A.K.B.; data curation, A.K.B.; writing—original draft preparation, A.K.B.; writing—review and editing, M.M. and A.K.B.; visualization, A.K.B.; supervision, M.M. All authors have read and agreed to the published version of the manuscript.

**Funding:** This paper is the result of a study carried out at the Institute of Soil Science and Plant Cultivation, State Research Institute in Pulawy, and it was co-financed by the National (Polish) Centre for Research and Development (NCBiR), project: BIOproducts from lignocellulosic biomass derived from MArginal land to fill the Gap In Current national bioeconomy, No. BIOSTRATEG3/344253/2/NCBR/2017. This research acknowledges financial support from the Widening Program ERA Chair: project BioEcon (H2020), contract number: 669062.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
