Effects of the Intercropping of Maize with Soybean on the Growth, Development,and Quality of Soybean

In order to study the effects of the intercropping of maize with soybean on the growth, development and quality of soybeans, two spring soybean varieties Quandou No. 5（D1), Quandou No. 12（D2）and maize variety Jinbaitian 15（Y）in Fujian Province were used as the experimental materials. The growth dynamics, agronomic traits, quality, yield and economic output value of soybeans were analyzed and compared under the two planting modes of maize-soybean intercropping and monoculture （as the control group). The results showed that during the whole growth period, the plant height, leaf chlorophyll content and stem proportion of soybeans in the intercropping pattern were higher than those in the monocropping pattern, but the leaf area index and dry matter content of soybeans in the intercropping pattern were lower than those in the monocropping pattern. With the development of growth period, the plant height, chlorophyll content, leaf area index, root dry weight and leaf dry weight of Quandou No. 5 and Quandou No. 12 under different planting patterns increased first and then decreased, reaching the maximum at the seed-filling stage. The stem dry weight, pod dry weight and total dry matter reached the maximum at the mature stage. The proportion of stem first increased and then decreased, reaching the maximum at the flowering stage. The plant height, bottom pod height, node number of main stem, protein content and fat content of soybeans in the intercropping pattern were higher than those in the monoculture pattern, but the effective branch number, effective pod number per plant, seed number per plant, seed weight per plant and the 100-seed weight were lower than those in the monoculture pattern. The intercropping pattern significantly reduced maize yield and soybean yield, but significantly increased the total yield and economic output value. Compared with the maize monoculture, the yield of maize in YD1 and YD2 intercropping patterns decreased by 2.43% and 4.19%, respectively; the total yield of maize and soybean increased by 11.23% and 8.14%, respectively, and the economic output value increased by 5206.51 yuan·hm⁻² (24.28%）and 4272.69 yuan·hm⁻² (19.93%), respectively. Compared with the soybean monoculture, the yield of soybean in YD1 and YD2 intercropping patterns decreased by 38.26% and 41.57%, respectively, and the total yield of maize and soybean increased by 402.98% and 412.46%, respectively, and the economic output value increased by 17370.07 yuan·hm⁻² (187.26%）and 16860.81 yuan·hm⁻² (190.49%), respectively. The land equivalent ratio of the two intercropping patterns was greater than 1, indicating that the intercropping pattern had obvious advantages. In summary, compared with the two soybean varieties, Quandou NO. 5 had shorter plant height, lower bottom pod height and stem proportion, larger effective pod number per plant, seed number per plant and seed weight per plant, while the proportion of stems was small, and the total yield, economic output value and land equivalent ratio (LER) of intercropping were large, so it was more suitable for intercropping as the local soybean varieties in Quanzhou area.