Department of Engineering and Technologies, Faculty of Technics and Technologies, Trakia University, 6000 Stara Zagora, Bulgaria
Abstract. Grassland associations are natural resource, which in their proper use might affect the welfare and economic development of the region in which they are located. In Sakar and Strandja regions such herbaceous plant associations occupy about 107.3 thousand hectares. Only in those regions of the country there is a favorable combination of environmental and climatic conditions allowing almost all year round utilization of pasture grass associations. They are the main potential to supply feed for the animals. In this experiment, the goal is to tracce and identify the productivity of natural pasture grass associations in Sakar and Strandja mountain. Observations were performed on the most typical, the most common and most used pastures located in these regions. The density of the pasture types was established. A comparative analysis of productivity of fresh mass and dry pasture grass of Sakar and Strandja region was performed. The results show that the pasture types in Strandja region possess higher density and greater productivity than those in Sakar region. With the highest density in Sakar region are the grassland type Agrostis capillaris – Festuca fallax, with a density of up to 1972 pieces/m2 at least. In Strandja region pasture type Agrostis capillaris – Cynosurus cristatus – Lolium perenne reaches density 3716 pieces/m2. These types of pastures are distinguished with the highest productivity of fresh and dry biomass. In Sakar region from pastures of type Agrostis capillaris – Festuca fallax 16680 kg/ha green mass and 4920 kg /ha dry matter can be obtained, and in Strandja region from grassland of type Agrostis capillaris – Cynosurus cristatus – Lolium perenne, 31700 kg/ha fresh mass and 7380 kg/ha dry matter can be obtained.