Objective] Intercropping, as one of the most universal multiple cropping systems based on biodiversity, plays an important role in enhancing crop productivity for more efficient use of resources, such as land, light, temperature and water as well as reducing incidence of weeds, insects, pests and diseases to meet the future human demand. Cereal-legume relay intercropping system is commonly used in China, because of the different distances between maize and soybean which influence the PAR distribution above the soybean canopy within relay strip intercropping system, and it is not only bad to the development of canopy structure but also decreases the light interception of intercropped soybean, thus resulting in limited photosynthetic active radiation use efficiency of intercropped soybean which restricts the productivity of maize-soybean relay strip intercropping systems. Therefore, there is a need for exploring an optimum spatial-temporal configuration management of intercropping system based on competition so that light resources requirement of soybean can be realized in this system. [Method] An experiment with maize (Zea mays L.) cultivar Chuandan 418 and soybean (Glycine max L. Merr.) cultivar Gongxuan1 were used in this study. The relay strip intercropping systems were designed as the distances of maize intercropped with soybean were 40 cm (A),50 cm (B) and 60 cm (C), and both of maize monoculture (SM) and soybean monoculture (SSB) were used as control. The soybean population canopy structure, light interception, dry matter weight in the relay strip intercropping combinations were measured and analyzed under maize/soybean relay strip intercropping systems in order to optimize the reasonable group configuration.[Result] The PAR density was different above the soybean canopy under different maize-soybean relay strip intercropping systems, and lower than SSB significantly (P<0.05). During the co-growth stage of maize and soybean, the PAR density occurred in treatment A was lower than that in treatments B and C by 44.1% and 60.4%, respectively. This means that the PAR density decreased as the degree of low light stress increasing due to the distance between maize and soybean decreased. The LAI, LA and plant height of intercropped soybean varied considerably in different maize-soybean relay strip intercropping systems. During the stages of V5, V7 and R1, the LAI of treatment B was higher than treatment A and treatment C significantly. Treatment B was higher than that in treatments C and A by 16.4%, 13.1%, 12% and 30.3%, 32.2%, 29.3%. LA of treatment B was higher than that in treatments C and A by 15%, 16%, 14% and 34%,31%,26%. Plant height of treatment B was lower than that in treatments C and A by 7%, 8.8%, 7.9% and 13.5%, 16.7%, 14.8%, which means that suitable soybean canopy structure can improve RUE. The LI of intercropped soybean was decreased significantly under different maize-soybean relay strip intercropping. During the stages of V5, V7 and R1, the LI of treatments A and C was lower than that in treatment B by 43%, 22%, 33% and 21%, 10%, 17%. A positive correlation of LAI and LI was significant (0.977**), which means that LAI might be the main factor due to the LI increasing. The photosynthetic active radiation use efficiency of intercropped soybean varied considerably in different maize-soybean relay strip intercropping systems. During the stages of V5, V7 and R1, the RUE of treatment B was higher than that in treatments C and A by 8.6%, 7%, 5.8% and 40%, 23%, 13%. The dry matter weight of soybean in all intercropping systems was lower than monoculture significantly (P<0.05), and varied considerably in different maize and soybean relay strip intercropping systems. During the stages of V5, V7 and R1, the dry matter weight of treatments A and C was lower than that in treatment B by 59%, 36%, 41% and 27%, 16% and 22%. A positive correlation of DMW and LI was significant (0.989**), which means that the dry matter increased with the light interception increasing. The yield of intercropped soybean and total yield varied considerably in different maize and soybean relay strip intercropping systems(P<0.05). The yield of treatment B was higher than that in treatments C and A by 10% and 27%, the total yield of treatment B was higher than that in treatments C and A by 1% and 3%. This means that the yield of intercropped soybean increased/decreased as influenced by the intensified low light stress due to the difference of distance between maize and soybean. [Conclusion]In this case, suitable distance of maize and soybean configuration could optimize intercropped soybean canopy structure, improve the light use efficiency and enhance yield.%【目的】研究不同行距的玉豆间距带状套作组合对大豆冠层结构特征与光能利用的影响，为制定适宜的群体配置提供理论依据。【方法】以四川省主推玉米和大豆品种“川单418”和“贡选1号”为试材，设计（A）玉豆间距40 cm（大豆窄行行距70 cm）、（B）玉豆间距50 cm（大豆窄行行距50 cm）、（C）玉豆间距60 cm（大豆窄行行距30 cm）3种玉豆带状套作组合，并以单作玉米（SM）和单作大豆（SSB）作为对照，对带状套作大豆冠层结构、光能截获量、干物质重等指标进行测定分析。【结果】（1）不同带状套作大豆群体冠层上方的 PAR 存在显著差异，且均显著低于 SSB（P＜0.05）。玉豆共生期间，处理 A 大豆群体冠层上方的 PAR 与处理 B 和 C 相比，分别低44.1%和60.4%。这说明由于处理 A 缩短了玉豆间距，加剧了玉米对大豆的遮荫程度，从而降低了大豆群体可利用的有限光照资源。（2）不同带状套作大豆群体的 LAI、叶倾角和株高均呈现显著差异（P＜0.05），在大豆V5、V7和 R1期，处理 B 比处理 C 和处理 A 的 LAI 分别提高了16.4%、13.1%、12%和30.3%、32.2%、29.3%。叶倾角比处理 C 和处理 A 分别提高了15%、16%、14%和34%、31%、26%。株高比处理 C 和处理 A 分别减低了7%、8.8%、7.9%和13.5%、16.7%、14.8%。说明适宜的玉豆间距可以提高套作大豆的 LAI，调整更加合理的叶倾角和株高，优化植株形态特征，实现光能在大豆群体内的均匀分布，有利于提高大豆的光能利用效率。（3）不同带状套作大豆光能截获量呈现显著差异（P＜0.05）。在大豆 V5、V7和 R1期间，处理 A 与处理 B 相比光能截获量分别降低了43%、22%和33%，处理 C 与处理 B 相比则分别降低了21%、10%和17%，LAI 与光能截获量存在显著的正相关关系（0.977**）,说明在玉豆间距为50 cm 时增加了大豆群体的 LAI，从而提高了光能截获量。（4）不同带状套作大豆光能利用率呈现显著差异（P＜0.05）。在大豆 V5、V7和 R1期，处理 B 与处理 C 相比光能利用率分别提高了8.6%、7.0%和5.8%，处理 B 与处理 A 相比则分别提高了40%、23%和13%。（5）不同带状套作大豆群体的干物质重均显著低于 SSB，且处理间呈显著性差异（P＜0.05）。在大豆 V5、V7和 R1期，处理 A 与处理 B 相比分别降低了59%、36%和41%，处理 C 与处理 B 相比则分别降低了27%、16%和22%，DMW 与光能截获量存在显著的正相关关系（0.989**），说明在玉豆间距为50 cm 时增加了大豆群体的光能截获量，从而提高了大豆群体干物质的积累。（6）不同带状套作大豆群体产量及总产量存在显著性差异（P＜0.05）。其中处理 B 的大豆产量分别比处理 C 和处理 A 提高了10%和27%，总产量比处理 C 和处理 A 提高了1%和3%。说明随着玉豆间距的缩短，大豆弱光胁迫程度的增加，大豆产量呈下降趋势。【结论】本试验条件下，以玉豆间距为50 cm 的玉豆带状套作种植模式可以优化大豆群体冠层结构、提高光能利用率和产量。
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