FORAGE PRODUCTIVITY AND CHEMICAL COMPOSITION OF WINTER VETCH (VICIA VILLOSA ROTH.) DEPENDING ON SOWING DATE AND NITROGEN FERTILIZING

摘要

Forage productivity and chemical composition of winter vetch (Vicia villoss Roth.) depending on sowing date and nitrogen fertilizing rates were studied In a two-factor field trial during the 2001 -2004 period in IFC Pleven. The long plot method was used. Four degrees of A factor (sowing date): 20-25 September; 5-10 October; 20-25 October; 5-10 November and four degrees of T factor (fertilizer rate, kg/da): T_0 - N_0P_0K_0, T_1 - N_4P_6K_4, T_2 - N_8P_6K_4. T_3 - N_(12)P_6K_4 were studied. The resultsshowed that winter vetch of Vicia villosa species was distinguished for high forage productivity. On average for the period of study the yields varied from 492.8 to 881 9 kg/da dry mass. The highest yield from harvesting at the phenological stage of flowering was formed at sowing date of 20-25 September. The dry mass formed for sowing in the period of 5-10 October, 20-25 October and 5-10 November was 5.5, 21.2 and 31.5 % lower, respectively. The increasing nitrogen fertilizer rates from N_0 to N_4 andN_8 increased the forage yield by 7.7 and 22.5%. The combined interaction of the two factors determined the sowing in the 20-25 September period and fertilizing rate of 8 kg N/da as an optimum variant. Both studied factors exerted an influence on crude protein content in aboveground mass of winter vetch. With prolongation of sowing time from first to second and third date, the crude protein content increased by 5.6 and 6.9%, respectively. As compared to the control (225.9 g/kg), the fertilizing increased the protein content by 5.4, 3.1 and 1.7% at N_4, N_8 and N_(12), respectively.