Agro biological peculiarities and biomass quality of liquorice, Glycyrrhiza glabra, under the conditions of Moldova

Abstract

Fabaceae species play a crucial role in protein production for human and animal diet, soil structure and environmentally friendly substitution for industrial N-fertilizers, valuable medicinal properties and multi-purpose use in various industries. The local ecotype of liquorice, Glycyrrhiza glabra, maintained in monoculture, served as object of study. The 3-year-old Glycyrrhiza glabra started vegetating 23 days later, the plants had moderate growth and development rates that allowed mowing them at the end of June, the green mass yield reached 4.38 kg/m2 , with moderate foliage (55 %), but reduced content of dry matter, protein (13.80 %), cellulose (29.40 %), minerals (5.40 %) and high amount of fats (3.65 %), nitrogen free extractive substances (47.75 %), essential amino acids (lysine, leucine, valine), in comparison with Onobrychis viciifolia. The liquorice forage had cell wall content 485 g/kg NDF and 323 g/kg ADF can be classified as good quality with relative feed value 122, dry matter digestibility 65.40 % and organic matter digestibility 56.70 %. The gas forming potential of Glycyrrhiza glabra (first mowing) reached 567 L/kg with 52.5 % methane, but biogas yields based on the concentration of acid detergent lignin and hemicellulose – 535 L/kg with 51.2 % methane, the potential methane production ranged from 3014 to 3278 m3 /ha, exceeding Onobrychis viciifolia. The briquettes of Glycyrrhiza glabra were distinguished by moderate specific density (873 kg/m3 ), gross calorific value (18.7 MJ/kg) and ash content (1.7 %). The theoretical ethanol potential from structural carbohydrates dry biomass averaged 511 L/t for Glycyrrhiza glabra, compared to 485 L/t corn stalks.