Biomass formation and yield performance in diverse multicrops and their potential for biofuel use in short-growing boreal climate conditions

Herbaceous plant biomass is an important resource for energy production and an effective strategy to ensure energy supply independence. Growing agricultural plant mixtures (multicrops) contributes to increasing biomass yields, enhancing farm biodiversity, improving soil health, and promoting environmental sustainability. However, most crop mixtures have not been studied at all. For this reason, stationary field experiment was conducted from 2020 to 2022 at Vytautas Magnus University, Agriculture Academy, Kaunas reg., Lithuania. The aim of the study was to evaluate the development and productivity of maize, industrial hemp and faba bean single crops and its binary and ternary mixtures, as well as the related energy and environmental aspects of the applied agrotechnologies, under short growing season conditions. Faba bean ecosystem services improved maize and industrial hemp growth in mixtures, increasing plant height by 14%, leaf assimilation area by 24%, and chlorophyll index by 19%, indicating enhanced nitrogen availability and photosynthetic activity in companion crops. Although biomass of individual species decreased in more diverse mixtures, total plot biomass increased, with the ternary maize-hemp-faba bean crop producing 4-8 times more dried biomass than single crops in the first year. The ternary system achieved the highest Comprehensive evaluation index (CEI = 4.54) and the greatest net energy yield (367,668 MJ ha⁻¹) despite higher fuel consumption (103.3 L ha⁻¹). Pellets produced from ternary biomass met quality standards (density 1238 kg m⁻³, ash 6%, ash shrinkage temperature 1042 °C), while Life cycle assessment showed lower environmental impacts for mixed-crop biomass compared with single maize crop (29.1 kg CO₂ eq GJ⁻¹). Overall, diversified cropping systems demonstrate strong potential for sustainable biomass production and environmentally efficient bioenergy generation.