Effects of planting patterns on forage yield and nutritional quality in different alpine ecological regions

This study examined the production performance of oats (Avena sativa) sown in mixtures with feed pea (Pisum sativum), common vetch (Vicia sativa), and broad bean (V. faba), as well as the individual sowing of these four crops in different alpine ecozones. The objective was to identify the optimal planting pattern for each ecological region, which could provide a theoretical basis for the artificial planting of mixed grassland sowing in different alpine ecozones. The results include: 1) Among the mixed combinations, the oat + feed pea combination had the highest hay yield (10.56 t·ha⁻¹) and crude protein content (16.15%). The crude protein content, soluble sugar content, crude fat content, and neutral detergent fiber content of the mixed sowing combination all fell between those of oats and bean unicast. 2) The average plant height for both oats and beans first increased and then decreased with an increase in altitude gradient in all regions. The highest hay yield in Menyuan County was 9.78 t·ha⁻¹. The crude protein content in Guinan County decreased with altitude, and the highest crude protein content in Guinan County was 17.69%. 3) Through comprehensive evaluation, we identified optimal planting combinations for each ecological area: oats + feed pea in Menyuan and Huangzhong Counties, oats + broad bean in Guinan County, and oats + common vetch in Gonghe County. The hay yields were 13.00, 10.63, 10.59, and 10.73 t·ha⁻¹, and the crude protein contents were 14.65%, 16.11%, 13.56%, and 12.01% in each region, respectively. Compared with oats monocot, the best-mixed sowing combinations increased the hay yield in each ecological area by 48.57% (Menyuan), 23.17% (Huangzhong), 23.00% (Guinan), and 47.80% (Gonghe).