SUBTERRANEAN CLOVER (TRIFOLIUM SUBTERRANEUM L.) AS A PROMISING FORAGE SPECIES IN BULGARIA

摘要

The paper presents an overview of the possibility to use the subterranean clover (Trifolium subterraneum L.) (an annual leguminous self-seeding species, widespread component in the pastures of the temperate areas of Central and Northern Europe and America) for the forage production in Bulgaria. The biological and ecological characteristics of the species are given. On the basis of researches (pot and field trials), mainly performed in the Institute of Forage Crops, Pleven, Bulgaria and their results,the conclusions are drawn as for the using of subterranean clover as a forage resource under the climatic conditions of the country. When sown at an appropriate time in the autumn, it establishes a uniform stand before the beginning of the permanent cold spell and grows up early in the spring and forms a dense sward. The subterranean clover may be included in mixtures with the following components: legumes - birdsfoot trefoil and sainfoin and grasses - cocksfoot, tall fescue, perennial ryegrass and crested wheatgrass. It decreases weed infestation, increases productivity and persistence of the pasture systems. Composition of the natural communities, in which it participates, shows that it is resistant to overgrazing, nitrification and ruderalization by domestic animals. Due to its self-seeding capacity, it may be used for under-sowing of degraded seed production stands. On the basis of its occurrence in different parts of the country and in the natural vegetation, the species is promising for establishment of forage crops. The participation of the subterranean clover in the perennial swards is also a tool to increase the biodiversity in the agrophytocoenosis. Subterranean clover as a component of sown pasture swards has practical applicability underthe climatic conditions of Bulgaria.