Isotope Tracer Technique·Ecology and Environment·Physiology
TIAN Yixin, ZHU Jinying, LI Chunyan, ZHU Guanxiong, GAO Qi, WANG Chunyu, HUA Fangjing, GAO Fengju
In order to explore the effect of intercropping patterns of maize/soybean intercropping system, maize Denghai 605 and soybean Qihuang 34 were used as experimental materials, and four intercropping patterns were set up: 2 rows of maize/4 rows of soybean (T2∶4), 2 rows of maize/6 rows of soybean (T2∶6), 3 rows of maize/4 rows of soybean (T3∶4), 3 rows of maize/6 rows of soybean (T3∶6), and maize monoculture (CKM) and soybean monoculture (CKS) were used as control. The effects of different intercropping patterns on crop agronomic traits, photosynthetic characteristics, yield value, yield advantage index and interspecific competitiveness were measured. The results showed that ear length, ear diameter, ear row number, grain weight per ear and leaf photosynthetic indexes (Tr、Gs、Pn、Ci) at R1 and R5 stages were better than those of T3∶4 and CKM at T2∶6, T2∶4 and T3∶6, respectively. Branches, effective pods, seed number per plant and leaf photosynthetic indexes (Tr, Gs, Pn) of R2 and R6 stages were all lower than CKS, Ciwas higher than CKS, and T2∶6, T2∶4, T3∶6 models were all better than T3∶4. The total yield and output value of T2∶6, T2∶4, T3∶6 intercropping systems were higher than those of T3∶4 and CKM. Compared to CKM, the total yield was increased by 8.22%, 6.51%, 5.91%, and the total output value was increased by 39.46%, 31.55%, 31.26%, respectively. The land equivalent ratio (LER) values ranged from 1.32 to 1.51, the intercropping advantage (IA) values ranged from 3 981.41 to 5 460.26 kg·hm-2, the actual yield loss (AFL)values ranged from 0.67 to 1.60, and the relative crowding index (K)values ranged from 6.69 to 11.82, all of which had yield advantages, especially in T2∶6, T2∶4 and T3∶6 modes. Under the model of T2∶6, the soybean competition ratio (CRs) was greater than 1, the maize competition ratio (CRm) was less than 1, the maize aggressiveness (Am) was less than 0, and the soybean aggressiveness (As) was greater than 0 incdicating that the competitive ability of soybean was stronger than that of maize, and under other patterns, maize was stronger. In conclusion, the intercropping patterns not only optimize the agronomic traits of maize, but also effectively reduced the shading and shading effects of maize on soybean, improved the photosynthetic performance of crops, and then increased the total yield and output value of the intercropping system. The T2∶6 pattern was the best, followed by T2∶4 and T3∶6. This study has important theoretical guidance and practical significance for promoting maize/soybean intercropping and exploring crop yield potential in northwest Shandong Province.