Screening of the best mixed ratio of Avena sativa and × Triticale Wittmack in the high-cold area of Guoluo, Qinghai Province

In order to determine the optimal ratio of Avena sativa and × Triticale Wittmack in the “Source of Three Rivers” region, a mixed treatment of A. sativa and × Triticale Wittmack was carried out in Gande County, Qinghai Province. The results showed that the mixed hay yield of the combination of A. sativa 60% + × Triticale Wittmack 40% was the highest of the five mixed treatments, at 13 605 kg·ha^–1, and the treatment was significantly higher than that of monoculture yields (P < 0.05). There was no significant difference between A. sativa 50% + × Triticale Wittmack 50% (P > 0.05). The plant height of A. sativa was greatest in the A. sativa 60% + × Triticale Wittmack 40% treatment. This was 6.5% higher than the value under A. sativa alone. The yield per plant and the underground biomass per plant of A. sativa treated with A. sativa 60% + × Triticale Wittmack 40% was significantly higher than that of A. sativa alone, and other mixed treatments (P < 0.05). The yield per plant of × Triticale Wittmack was highest in A. sativa 60% + × Triticale Wittmack 40%. The content of acid and neutral detergent fiber (ADF and NDF) of A. sativa and Triticale treated with A. sativa 60% + × Triticale Wittmack 40% was lower than that of the monocultures, and A. sativa 60% + × Triticale Wittmack 40% had the highest crude protein content. The comprehensive evaluation of the optimal ratios was carried out by using the relative values of hay yield, crude protein content, soluble sugar content, starch content, ADF and NDF content, and was determined as A. sativa 60% + × Triticale Wittmack 40%.