Exploration of the intercropping mode between silage corn and whole-plant soybean

This study aimed to explore the optimal mode of intercropping silage corn and soybeans to achieve the best yield and quality performance. This study used ‘Dica 688’ and ‘Pudou 5110’ as experimental materials, and set up four intercropping modes of maize soybean row ratios of 2 ꞉ 4 (M₂S₄), 2 ꞉ 6 (M₂S₆), 2 ꞉ 8 (M₂S₈), and 2 ꞉ 10 (M₂S₁₀), as well as maize (M) soybean (S) monoculture control. The yield, quality, water use efficiency, competitiveness index, and silage quality of different treatments were measured. The results demonstrated that M₂S₄ treatment presented the best yield performance, and the yield of the intercropping mode decreased with the increase of soybean planting rows. The nutritional indicators, such as protein content and relative feeding value of whole soybean in intercropping mode, were significantly reduced compared with monoculture treatment (3.03%～12.56%, 7.44%～24.88%) (P < 0.05), and there was no significant difference among the intercropping treatments. The protein content of intercropped corn significantly increased compared to monoculture treatment (8.81%～22.46%) (P < 0.05), demonstrating an increasing trend with the increase of soybean planting rows. The water consumption of corn monoculture was significantly higher than that of other treatments by 4.08%～10.04% (P < 0.05), and the water use efficiency of intercropping treatment was significantly higher than that of monoculture treatment, with an increase of 14.6%～36.7% (P < 0.05) compared to soybean monoculture treatment and an increase of 6.54%～20.88% compared to corn monoculture treatment. The water use efficiency of each intercropping treatment was M₂S₄ > M₂S₈ > M₂S₁₀ > M₂S₁₀. After mixing silage, the protein content increased by 27.5%～52.4% (P < 0.05) compared to corn silage alone, and the protein content increased with the increase of planting rows. The fat content increased by 5.93%～37.19%, and the relative feeding value increased by 6.7%～16.1% (P < 0.05). However, the relative feeding value of M₂S₁₀ decreased significantly compared to other intercropping treatments. Based on the above analysis, it is believed that the M₂S₄ model has the highest yield and water use efficiency. However, as the number of planting rows increases, its protein yield gradually increases. Comprehensive analysis shows that corn planting in two rows and soybean planting in 4～8 rows presented a better performance in terms of yield, quality, and water use efficiency; users can choose according to their protein needs for aquaculture.