Anotace:
Aim of this study was to determine the gross energy concentration of fresh, wilted and ensiled Rumex OK 2 (Rumex patientia L. x Rumex tianschanicus A.Los.) from spring months and June. Samples were collected in spring months and June of the year 2018. The plant of Rumex OK 2 consist in March mainly from rosette of leaves and the stalk is not higher than leaves, from April is stalk higher than rosette of leaves. The height of Rumex OK 2 during analysed months was following, March 60.96 ± 5.22 cm; April 114.70 ± 35.15 cm, May 168.31 ± 39.74 cm and June 197.41 ± 48.44 cm. Rumex OK 2 silage was made from wilted matter, with or without of addition of dried molasses. Gross energy was determined as the heat released after combustion of a sample (Leco AC 500) in MJ per kilogram of dry matter (DM) of the sample. The dry matter and gross energy concentration of fresh Rumex OK 2 increased during study, dry matter from 7.42% in March to 56.97% in June and gross energy from 18.00 MJ.kg-1 of DM in March to 18.88 MJ.kg-1 of DM in June. Statistically significant (P<0.05) higher concentration of dry matter, as well as gross energy was detected in wilted Rumex OK 2 samples and silages from May compared to April. Addition of dried molasses to wilted Rumex OK 2 did not affected concentration of gross energy in silages (P>0.05). From all analysed Rumex OK 2 samples the highest concentration of gross energy had silage from May with addition of dried molasses, 19.04 MJ.kg-1 of DM. The utilisation of Rumex OK 2 from spring months can by neither for bioenergy production as a source of renewable energy, or after evaluation of nutritive value as a source of energy and nutrients in animal nutrition in form of pasture and silage. Rumex OK 2 from summer months seems to be utilized only as a source of heat via direct combustion.