Effect of Application of Agrotechnical Measures in Unused Natural Meadows and Pastures in Smolyan Region

Abstract

Abstract. During the period 2010-2012, two experiments were carried out in unused natural meadows and pastures at altitude of 1100 m and 1530 m, with sample plot size of 10 m². Five agro technical measures were studied in the following variants: In natural meadows: 1. without application of measures (control); 2. cleaning of plots from trees, shrubs and stones, cutting and harvesting; 3. cleaning of plots from trees, shrubs and stones, nitrogen-phosphorus fertilization with 80 kg N ha ) and phosphorus (90 kg P 2 O 5 ha -1 ) fertilization and respectively with organic-mineral fertilization-manure 7 t ha -1 , 60 kg N ha -1 and 70 kg P 2 O 5 ha -1 contributed to the increase of the grass stands productivity of unused natural meadows in the highest degree. Average for the period of investigation, more green and dry mass were obtained, exceeding the control with 69.9 and 120.5% and with 54.0 and 74.0%, richer in the crude protein, the crude fat and the calcium. Grazing of the old grass cover of unused natural pastures combined with application of mineral fertilizers 75 kg N ha , 60 kg P 2 O 5 ha -1 led to an acceleration of growth and development of the grass plants and increase the productivity of grass stands. The resulting green mass (12.2-13.2 t ha -1 ) was higher than the control and with higher nutritive value. The applied measures contributed to increase the share of grasses in the grass stand. The fertilization with organic and mineral fertilizers contributed to increase the content of crude protein in the forage and decrease the crude fibre.