The Influence of Different Oat–Pea Mixed Cropping Ratios in a Corral Coupled with Lactic Acid Bacteria Inoculation on Silage Quality

This study was carried out in Haiyan County, Qinghai Province. The aim was to explore the impacts of a mixed cropping of oats and peas sown in a corral with the addition of lactic acid bacteria (LAB) including Lactobacillus plantarum, Lactobacillus buchneri, and Pediococcus pentosaceus on silage quality, so as to alleviate the shortage of winter forages. A two-factor experimental design was adopted. For the treatments with and without LAB addition, the ratios of oat to pea in the plots were set as 1:0, 2:1, 1:1, 1:2, and 0:1, respectively. Subsequently, the materials were subjected to the silage process at 19 °C for 45 days. Silage samples were collected to determine their sensory quality, nutritional quality, and fermentation quality in order to evaluate the fermentation effect. The results showed that mixed cropping could improve forage quality. Without the addition of LAB, the soluble sugar content of the mixture of oats and peas in a 2:1 ratio increased significantly by 21.9% compared with that of the pea monoculture (p < 0.05), and the crude protein content of the mixture of oats and peas in a 1:2 ratio increased by 31.6% compared with that of the oat monoculture (p < 0.05). Meanwhile, the contents of acid and neutral detergent fibers decreased significantly (p < 0.05) with the increase in pea radios. After the addition of LAB, different results were obtained due to the fermentation of lactic acid bacteria during the silage process. The pH value decreased, the lactic acid content increased significantly, and the ratio of ammonia nitrogen to total nitrogen decreased significantly. Based on comprehensive analysis, an appropriate mixed cropping ratio combined with LAB addition can improve silage quality. Among them, the mixture of oats and peas in a 1:1 ratio with LAB addition for silage had the highest silage score, indicating good silage and feed quality. I While with or without LAB addition, the ratio of 1:2 is the best, followed by the ratio of 1:1.