Abstract Different planting pattern affects the leaf senescence of maize under intercropping systems, which regulate the grain yield of maize plants. In this study, we observed that a narrow-wide-row planting pattern in maize soybean relay intercropping system (MS) improved the leaf greenness and green leaf area, delayed the leaf senescence process in maize and increased the photosynthetic rate of maize leaves during the reproductive stages of maize in MS. In a three-year field experiment, soybean was relay-intercropped with maize under different planting patterns (1M1S, “50 cm + 50 cm” 1-row of maize and 1-row of soybean with an equal row distance of 50 cm; and 2M2S, “40 cm + 160 cm” narrow-wide-row planting pattern, where 2-rows of maize were planted in narrow rows, and 2-rows of soybean were planted in wide rows, and 60 cm distance was maintained between the rows of maize and soybean) of MS, and both planting patterns of MS were compared with sole cropping systems of maize and soybean. Compared with 1M1S, planting pattern 2M2S significantly increased the number of green leaves (by 36%), leaf greenness (by 17%), and leaf nitrogen content (by 13%) at the dent stage (R5). The improved leaf nitrogen content in 2M2S at R5 significantly increased the green leaf area (by 16%, from 4170 cm2 plant−1 in 1M1S to 4960 cm2 plant−1 in 2M2S) of maize, indicating that leaf senescence of maize plants was delayed, which in turn significantly enhanced the photosynthetic rate of maize leaves at R5 by 57% in 2017, 75% in 2018 and 49% in 2019 than 1M1S. Overall, in 1M1S and 2M2S, relay-cropped maize produced 100%, and 89% of sole maize yield and relay-cropped soybean produced 27% and 66% of sole soybean yield, respectively. Importantly, compared to 1M1S, the decline of maize yield by 11% in 2M2S was compensated by a substantial increase in soybean yield by 147%, and 2M2S achieved the highest land equivalent ratio value of 1.54 compared to the land equivalent ratio value of 1.27 in 1M1S. Our results suggest that by selecting the appropriate planting pattern or stay-green maize hybrids, we can improve the land equivalent ratio of maize soybean relay intercropping system.

中文翻译：

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延迟玉米叶片衰老增加了玉米大豆中继间作系统的土地当量比

摘要 间作制度下不同的种植方式影响玉米叶片衰老，进而调节玉米植株的籽粒产量。在这项研究中，我们观察到玉米大豆中继间作系统（MS）中的窄宽行种植模式改善了叶片的绿度和绿叶面积，延迟了玉米的叶片衰老过程并提高了玉米叶片的光合速率。 MS 中玉米的生殖阶段。在为期三年的田间试验中，大豆与玉米在不同种植模式（1M1S，“50 cm + 50 cm”1行玉米和1行大豆等距50 cm）下套作；和2M2S，“40cm+160cm”窄宽行种植模式，其中玉米2行窄行，大豆2行宽行，MS 的玉米和大豆行之间保持 60 cm 的距离，并将 MS 的两种种植模式与玉米和大豆的单一种植系统进行比较。与1M1S相比，种植模式2M2S显着增加了凹痕期（R5）的绿叶数量（36%）、叶绿度（17%）和叶氮含量（13%）。R5 时 2M2S 叶片氮含量的提高显着增加了玉米的绿叶面积（增加了 16%，从 1M1S 的 4170 cm2 植物-1 到 2M2S 的 4960 cm2 植物-1），表明玉米植物的叶片衰老被延迟，反过来，与 1M1S 相比，2017 年、2018 年和 2019 年分别显着提高了 R5 玉米叶片的光合速率 57%、75% 和 49%。总体而言，在 1M1S 和 2M2S 中，连作玉米产量 100%，和 89% 的单一玉米产量和连作大豆分别产生了 27% 和 66% 的单一大豆产量。重要的是，与1M1S相比，2M2S玉米产量下降11%被大豆产量大幅增加147%所弥补，2M2S实现了最高土地当量比值1.54，而2M2S的土地当量比值1.27 1M1S。我们的研究结果表明，通过选择合适的种植模式或留绿玉米杂交种，可以提高玉米大豆套作系统的土地当量比。54 与 1M1S 中的土地当量比值 1.27 相比。我们的研究结果表明，通过选择合适的种植模式或留绿玉米杂交种，可以提高玉米大豆套作系统的土地当量比。54 与 1M1S 中的土地当量比值 1.27 相比。我们的研究结果表明，通过选择合适的种植模式或留绿玉米杂交种，可以提高玉米大豆套作系统的土地当量比。