INFLUENCE OF DIFFERENT WAYS OF HARVESTING ON SOME FORAGE PRODUCTIVE AND CHEMICAL INDICATORS FOR A NATURAL MEADOW OF AGROSTIS CAPILLARIS-FESTUCA FALLAX TYPE IN THE RHODOPE MOUNTAINS (SOUTHERN BULGARIA)

摘要

The experiment was conducted with a natural meadow of Agrostis capillaris-Festuca fallax type in the Rhodope Mountains (Smolyan region, Southern Bulgaria). The block-method in four repetitions and the harvesting plot area of 10 m2 with the following ways of use by years and undergrowths was used. The object of this study included annually (in 4 variants) and in the alternate years (in 3 variants) hay-grazing - use, grazing-hay - use, hay-grazing-grazing - use or only grazing-use of the particular regrowths in the different years. The harvesting in grazing-usе mode (grazing imitation) was accomplished in height of the grass stand 10-12 cm. The harvesting in hay-making mode was accomplished in flowering phenophase of the grasses. It was established that the studying different ways оf harvesting given comparatively high dry matter yields. The following indicators were estimated: 1. Dry mass (DM) yield (in t/ha) - it was established by drying constant weight at 105 Celsius degree in muffle-oven of 0.5 kg green mass samples, taken immediately after cutting each trial plot and repetition; 2. Chemical composition of the absolutely dry matter included crude protein and crude fiber contents of the basic botanical groups (grasses and legumes) in the grass stand. They were determined by infrared spectroscopy on InfraAlyzer–400. For that purpose were done calibrations of 50 plant samples for each botanical group as every tenth sample was examined by analyzing after Weende-method. The crude fat content was determined after Soxlet- method, the crude ash – by weighing after dry calcination in a muffle-oven and the nitrogen-free extract substances (NFES) as an amount among the crude protein, the crude fiber, the crude fat and the crude ash. The crude protein and crude fiber of the grass biomass were in well-expressive opposite dependence. The others studied chemical indicators (crude fat, crude ash and NFES) had a less influence on the ways that were used for the grass stand.