Abstract: In order to provide an optimum reference for local forage production, this experiment evaluated the silage quality of oat-vetch and oat-hairy-vetch sown with different mix ratios and produced with different moisture contents and silage methods in the pastoral area of southern Qinghai. An initial comparison of forage production indicated that mixes of Denmark No.444 oat+Ximu333 vetch and Denmark No.444+hairy-vetch performed the best as silage raw materials. The test was located in the Henan Mongolian Autonomous County (elevation 3600 m, longitude and latitude 34°45' N, 101°34' E) of Qinghai Province. The trial design included different sowing mix ratios (18∶2、17∶3、16∶4、15∶5), moisture contents (40%, 45%, 50%, 55%, 60%, 65%, 70%) and different silage methods (whole silage, chopped silage). Oat-vetch and oat-hairy-vetch seeds were mixed and sown on 20 May 2015. The sowing ratio of 15∶5 oat-vetch produced the highest yields at 12525 kg·ha^-1. The oat and vetch forages were harvested at the milk stage, then wilted and their primary moisture contents tested, with the forages then sprayed to obtain the target moisture contents. Two silage methods were tested-long silage, in which whole plants were baled and ensiled, and short silage, with the forage cut to 3-5 cm before ensiling. All treatments had 6 replicates. Bales were sampled at 150 days after ensiling. Based on the DLG silage evaluation system, there were 35 treatments with sensory scores in the range 20-16 (Quality-level 1), accounting for 50.0% of the total treatments. There were 18 treatments with scores 15-10 (Quality-level 2, 25.7% of the total), 15 treatments with scores 9-5 (Quality-level 3, 21.4% of the total) and 2 treatments with scores 4-0 (Quality-level 4, 2.9% of the total). Of all the 70 treatments, the chopped silage sensory score was at the highest level when the raw material moisture content was in the range of 50%-60%. Silage quality was also evaluated using four indexes: pH value, lactic acid content, crude protein content and AN/TN ratio. The results indicated that in terms of yield, sensory and chemical evaluation, the treatment with sowing mix ratios at 15∶5, moisture contents at 50% and chopped silage, produces the best quality forage.

Key words: oat (Avena sativa), common vetch (Vicia sativa), hairy vetch (Vicia villosa), mix-sowing, moisture content, silage