State and Changes of the Types of Natural Pasture Compositions in Strandzha under the Influence of the Climatographic Factors

Abstract

The observations were made during the period 2008 – 2010 on the vegetative development, state and changes on the type natural pasture swards in Strandzha, like was studied the influence of the climatographic factors. The observations were made on five type pasture swards: 1) Hordeum crinitum – Trifolium nigrescens; 2) Cynusurus cristatus – Lolium perenne – Trifolium subteraneum; 3) Agrostis vulgaris – Cynusurus cristatus – Lolium perenne; 4) Cynodon dactilon – Lolium perenne; 5) Avena flavescens – Cynusurus cristatus – Lolium perenne.
It was determined, that the natural pastures in Strandzha from type Hordeum crinitum - Trifolium nigrescens; Cynusurus cristatus – Lolium perenne – Trifolium subteraneum and Avena flavescens – Cynusurus cristatus – Lolium perenne, situated on a more big height and roundabout from forest sections, they have more favorable combination of the climatic indicators and a good water-ensure. This given possibility for 1 mowing, almost all the year pasture use, as the height of their sward range from 50 and 73 cm.
The most essentially changes are observed at the pastures of type Cynodon dactilon – Lolium perenne and Agrostis vulgaris – Cynusurus cristatus – Lolium perenne situated on a more small height, like the unfavorable manifest of the climatographic factors was reflected negative on the vegetative development of swards and their grass composition was reduce.
The height of there swards reduced to 30 – 40 cm. These type swards are use like pasture during the spring and autumn, and during the summer come out in “summer rest”.