Impact of Biological Fertilizing on the Composition and Productivity of Degraded Mesophytic Meadow in Mountain Conditions

A field experiment was conducted at the Research Institute of Mountain Stockbreeding and Agriculture (Bulgaria) to establish the impact of annual organic fertilizing on the bioproductive characteristics of a degraded grassland with a predominant share of grasses in mountain conditions. A significant effect on the biological productivity of the at all levels of fertilizing was found. The excess in the values of the indicator compared to the control was from 49.1% to 98.8%. Desired changes in the individual groups and species of the botanical composition of the pastures were observed. Lotus corniculatus, Vicia sativa, Trifolium hybridum (from legumes) and Festuca arundinaceae Scherb., Festuca rubra, Anthoxanthum odoratum, Agrostis capillaris (grasses) showed the highest resistance and adaptability to mountain conditions. The elimination of Trifolium repens, Trifolium aureum Pollich., Vicia villosa Roth. (second year), Vicia cracca, Medicago lupulina (third year) and Trifolium pratense (fourth year) from the composition of the grass mass affected the fodder and nutritional value of the grasslands. The grasslands treated with 1000 and 4000 kg/da dose of manure have the highest concentration of crude protein, respectively 14.39 and 14.05%. The values of the indicator exceeded the control by 20.0% and 17.2%, respectively. With a slight difference in protein content were grasslands treated with 2000 kg/da (12.03%) and 3000 kg/da (12.52%). The excess compared to the control variants was 0.3% и 4.4%, respectively. The highest fiber (44.37%) is the biomass with an imported dose of 3000 kg/da. The fertilizing variants registered with 2.3% to 11.4% higher content of crude ash compared to the control.