Zinc Accumulation Capacity of the Meadow Vegetation in Different Mountain Areas (South and Central Bulgaria)

V. KAFEDJIEV1, Tz. ODJAKOVA1, L. ANGELOW2, P. TODOROVA3 and I. PETROVA2
1 Complex Experimental Station, BG-4700 Smolyan, Bulgaria
2 Institute of Animal Breeding, BG-2232 Kostinbrod, Bulgaria
3 Institute of Mountain Stockbreeding and Agriculture, BG-5600 Troyan, Bulgaria

Abstract

KAFEDJIEV, V., Tz. ODJAKOVA, L. ANGELOW, P. TODOROVA and I. PETROVA, 2001. Zinc accumulation capacity of the meadow vegetation in different mountain areas (South and Central Bulgaria). Bulg. J. Agric. Sci., 7: 445-449

The study traced out the dynamics of the transfer of the essential trace element zinc to grass vegetation during the grazing period (May-September) by using 120 and 65 plant samples from pastures in the Middle Rhodope and the Balkan Mountain, respectively.
Data on zinc content during the entire trial period showed a marginal zinc offer only in the area of Troyan (Balkan Mountain). Zinc levels correlated very well with the geological origin of sites. The importance of low transfer was closely related to the precipitation and the pH change in the upper soil layer. In the region of the Rhodope Mountain a normal zinc concentration was found (55-60 mg/kg DM) during the whole grazing period with the exception of August (29.7 mg/kg DM). Pasture grass from alpine pastures in the Rhodope Mountain (over 1400 m altitude) contained from 62.5 mg Zn/kg DM in June to 51.4 mg Zn/kg DM in August. Flora developing on the syenite and gneiss geological formations provided entirely zinc requirements for growing lambs and lactating ewes during the whole grazing period.
The dynamic changes in the zinc content of pasture grass with the advance of vegetation demanded after June a correction of zinc offer to growing, gravid and lactating ruminants raised in the area of Troyan, calculated to about 10 to 20 mg Zn daily. In September, the concentration of zinc in the new meadow grass reached the initial values obtained at the beginning of the pasture period.

Key words: meadow vegetation, zinc offer, requirement, zinc supply