Haying is the most common method of storing forages. Hay is the major source of essential fiber, energy, protein, vitamins and minerals for many classes of livestock during the winter season. Hay quality varies due to different factors such as plant species, fertilization, stage of maturity, harvesting practices/curing and storage. Because of climate change and the extension of the areas with degraded and salinized soils, it is necessary to mobilize plant species from local spontaneous flora that would provide the necessary amounts of forage nutrients under these unfavourable conditions. In recent years, there has been a renewed interest in Fabaceae species and their use in animal diets because they possess important nutritional properties such as high palatability and high nutritional value. Some species containing moderate concentrations of condensed tannins, confer bloat resistance, increased flow of non-ammonia N and essential amino acids to the small intestine, and increased plasma levels of sulphur amino acids for body synthetic reactions, other legume species offer opportunities for improving animal health with less medication, due to the presence of bioactive secondary metabolites (Goriachev et al., 1970; Messman et al., 1994; Moeller et al., 2012; Mueller-Harvey, 2006; Toderich et al., 2015). The aim of this study was to evaluate the quality of the hay from Coronilla varia, Glycyrrhiza glabra and Onobriychis arenaria, as well as the possibility of using it as feed for ruminant animals and as feedstock for biomethane production. The local ecotypes of crown vetch – Coronilla varia, liquorice – Glycyrrhiza glabra and sand sainfoin – Onobriychis arenaria grown in monoculture on an experimental plot in «Alexandru Ciubotaru» National Botanical Garden (Institute), Chişinău, latitude 46°58′25.7″ N and longitude 28°52′57.8″ E, served as subjects of the research. The studied local ecotypes were cut for the first time in the budding-flowering stage. The prepared hay was dried directly in the field. Some assessments of the main biochemical parameters: crude protein (CP), crude fibre (CF), ash (CA), acid detergent fibre (ADF), neutral detergent fibre (NDF), acid detergent lignin (ADL) have been determined by near infrared spectroscopy (NIRS) technique, using the PERTEN DA 7200 at the Research and Development Institute for Grassland Braşov, Romania. The concentration of hemicellulose (HC) and cellulose (Cel), the digestible dry matter (DDM), the relative feed value (RFV), the digestible energy (DE), the metabolizable energy (ME) and the net energy for lactation (NEl) were calculated according to standard procedures. The carbon content of the substrates was calculated using an empirical equation according to Badger et al. (Badger et al., 1979), the biochemical biogas potential (Yb) and the methane potential (Ym) were calculated according to the equations of Dandikas et al. (Dandikas et al., 2015). As a result of the research carried out, it was established that Coronilla varia hay consists of dark green leaves and greenish stems, has pleasant smell, the leaves remain attached to the stems, and has reduced dust content. The Glycyrrhiza glabra hay has pleasant caramel smell, consists of light green leaves and yellowish green stems, the leaves stay attached to the stems, without dusty content. The Onobriychis arenaria hay has pleasant smell, consists of gray green leaves attached to the light green stems, without dusty content. The nutrient profile of the analysed hays is presented in Table 1. The hay was characterised by higher indices of crude protein, dry matter digestibility, energy content and relative feed value. The average values indicate similarities in acid detergent fibre, acid detergent lignin, cellulose protein energy concentration between crown vetch hay and sand sainfoin hay.The information about the nutritive value of Coronilla varia, Glycyrrhiza glabra and Onobriychis arenaria hays is still limited. Seim (Seim, 1966) found that Coronilla varia hay contained 17,1-17,7 % CP and 61,3-62,1 % IVDMD. Messman et al. (Messman et al., 1994) compared the protein concentration and reported that Coronilla varia contained 29,7 % CP in hay, but Medicago sativa – 26,9 % CP, respectively. Toderich et. al. (Toderich et al., 2015) showed that the hay produced from Glycyrrhiza glabra harvested in the flowering period was characterized by 132 g/kg CP, 48 g/kg crude fat, 334 g/kg CF, 417g/kg nitrogen free extract, 492.7 g/kg NDF, 82 g/kg ADL. Ryabinina (Ryabinina, 1998) reported that Onobrychis arenaria hay contained: 17,7 % CP, 4,45 % CA, 22,8 % CF, 45,6 % nitrogen free extract, 0,79 % Ca, 0,21 % P, 0.61 nutritive units/kg and 10,1 MJ/kg metabolizable energy. Dzyubenko & Abdushaeva (Dzyubenko et al., 2012) reported that Onobrychis arenaria hay contained: 15,4 % CP, 3,2 % crude fat, 6,2 % CA 24,9 % CF, 34,0 % nitrogen free extract and 0,54 nutritive units/kg. The biomethane derived from anaerobic digestion of organic substrates is a very promising potential source for heat production, electricity generation and transport fuel. The foam formation is considered one of the most frequent disturbances in biogas reactors. Using mixtures of legumes and tannin-containing plant species can minimize the foam formation in biogas reactors, with beneficial effect on methane production yield as well as on environmental protection (Moeller et. аl, 2012). The results regarding the quality of the investigated legume substrates and the potential biomethane are illustrated in Table 2. In the studied substrates, the C/N ratio is optimal and the biochemical methane potential reaches 321-330 L/kg VS.Conclusions. The local ecotypes of Coronilla varia, Glycyrrhiza glabra and Onobriychis arenaria can be used to establish temporary grasslands in order to prevent soil erosion, in monoculture or associated with other grasses, and the harvested mass can be used as hay for ruminants, or as a substrate for the production of biomethane and renewable energy. 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