A study has been conducted at the Experimental Station of Agriculture, Sredets to establish the effect of predecessor and mineral fertilization on chemical composition and energy value of wintering oats grain. The object of this study was wintering oat (Avena sativa L) variety Jubile cultivated after predecessors (A): stubble (A ), sorghum (Sorghum vulgare Pers) -(A ) and rape (Brassica napus var. oleifera L) -(A ) and fertilization, kg/ha – (B): N P K -B ; 1 2 3 40 100 50 1 N P K -B ; N P K -B and B control N P K .The study covers chemical analysis of wintering oats grain made by Weende method. Calculations for the 80 100 50 2 120 100 50 3 0 – 0 100 50. nutritive value of feed grain based on data obtained from chemical analysis were made (for ruminants) expressed in gross energy (GE) – MJ/kg dry substance, metabolizable energy (ME) – MJ/kg dry substance, feed units for milk ( FUM, kg) and feed units for growth (FUG, kg) of dry substance – by using empirical equations. It was found that the predecessors stubble and rape increase the content of crude protein, crude fat and crude fibers in oats by 10.5 and 12.1%, 5.2 and 3.9%, 5.6 and 1.2%. The content of minerals and nitrogen-free extract (NFE ) was the highest after predecessor sorghum. Increasing the doses of nitrogen fertilizer led to increasing the content of crude protein and fibers in grains on average by 14.4% and decreases the content of crude fats, ash and NFE by 7.0%, 3.2% and 3.4%, respectively. The differences in chemical composition of oat grains did not have a significant impact on its energy value expressed by GE, ME,
(FUM) and (FUG).
M. Dimitrova – Doneva, R. Petkova