Y. Naydenova, N. Georgieva, I. Nikolova
Abstract. During the period 2007-2009 in the Institute of Forage Crops, Pleven a two-factorial field experiment was carried out by the split plot method with the purpose of studying the influence of preparations with different biological effect, used single and combined on energy and protein feeding value of spring vetch. The results showed that the single and combined application of preparations Atonic, Masterblend and Confidor influenced positively the energy feeding value of spring vetch forage, increasing it by 1,0 to 5,8% for UFL and 6,0 to 7,7% for UFV. The highest mean value was established for treatment with combination Confidor-Masterblend followed by Confidor-Atonic. The combined application of the preparations was more effective (UFL-UFV: 0,765-0,666; FUM-FUG: 0,635-0,544) in comparison to the single (UFL-UFV: 0,758-0,656; FUM-FUG: 0,628-0,537). The protein feeding value (Total digestible protein) of spring vetch under influence of the preparations with different biological effect decreased in comparison with the control average by 8,0%. On the PDIN value the least effect had the treatment with Masterblend and combined by Confidor-Atonic and the largest – combined treatment by Confidor-Masterblend. In regard to PDIE value a similar tendency was established as the variation in the values was wicker. The treatment stage determined the preparation application at flowering stage as more effective reaching maximum values which exceed those at budding stage and at budding-flowering stages by 5,2 and 2,1% for PDIN and PDIE, respectively.