This study was conducted to determine the effect of nitrogen fertilizer levels and mixture of small grains on the productivity and quality of spring forage rape (Brassica napus) in the south region of Korea (Mokpo). The experiment was arranged in a split plot design with three replications. The main plots consisted of three different levels of nitrogen fertilizer (100, 150 and 200 kg/ha). The sub-plots consisted of five kinds of mixed small grain species (rye (Secale cereale), oat (Avena sativa), barley (Hordeum vulgare), italian ryegrass (Lolium multiflorum), and rape (B. napus) monoculture). The results were summarized as follows: (1) dry matter (DM) content of rye+rape and barley+rape mixtures increased by 2-3% compared to rape monoculture. The high level of nitrogen application increased the fresh matter yield and yield of rye+rape monoculture were higher than that of others; (2) dry matter yield of rye+rape mixture and rape monoculture with 200 kg/ha of nitrogen application were higher by 9449 and 9227 kg/ha, respectively; (3) the crude protein (CP) content of rape was high as 18.6% while average CP content was 16%. (4) The average total digestible nutrient (TDN) content showed high as 70%. It is suggested that the rye+rape mixture or rape monoculture would recommended for spring use of rape in the southern region of Korea.
