行距配置对冬小麦/白三叶草间作系统小麦群体结构和光合有效辐射的影响

Effect of row space on population structure and photosynthetic available radiation in winter wheat-white clover intercropping system

  • 摘要: 2008~2010 年冬小麦/白三叶草不同栽培方式试验(6 种小麦行距配置, 3 个行距×2 个播种量)研究表明,单作条件下, 小麦群体总茎数、叶面积指数、生物量及产量在行距25 cm 与30 cm 处理间差异不大, 均显著高于行距40 cm 处理。行距30 cm、播种量217.5 kg·hm-2 处理的籽粒产量和收获系数分别达7 857.8 kg·hm-2 和0.483。小麦抽穗期和花期, 行距30 cm 与40 cm 处理的冠层底部向上20 cm 处的光合有效辐射(PAR)值差异不大, 行间全天PAR 在50 μmol·m-2·s-1 以上的时间至少有8 h, 而单作条件下白三叶草光补偿点在30~50μmol·m-2·s-1 之间, 这预示着在行距30 cm 与40 cm 处理的小麦行间间作白三叶草能为白三叶草光合作用提供有效光能。行距30 cm 条件下, “小偃81”与“济麦22”单作以及分别与白三叶草间作处理试验表明, “小偃81”与白三叶草间作系统小麦生物量不受间作影响, 小麦叶面积指数与穗数高于“小偃81”单作。“济麦22”与白三叶草间作系统的3 项指标则低于“济麦22”单作。间作条件下, 白三叶草冠层顶部PAR 日变化呈单峰曲线, 冠层底部PAR 较小, 全天最大仅30 μmol·m-2·s-1。与“济麦22”相比, “小偃81”与白三叶草间作冠层底部PAR 全天日变化较小。因此, 行距30 cm 处理小麦行间适合间作白三叶草, 小麦品种“小偃81”比“济麦22”更适合与白三叶草间作。本研究结论可为华北平原发展冬小麦/白三叶草间作种植模式提供参考依据。

     

    Abstract: Winter wheat (Triticum aestivum L.) planted with several cropping patterns were intercropped with white clover (Trifolium repens L. vs Rivendel) in 2008~2010 cultivation seasons. Population structure, photosynthetic available radiation (PAR) and yield of wheat and intercropping system were investigated. Results of the experiment with six wheat cropping patterns (3 row spaces × 2 sowing rates) indicated that total stems, LAI, biomass and yield of wheat with 25 cm and 30 cm row spaces were significantly higher than those with 40 cm row space. The yield and harvest index of wheat with 30 cm row space and 217.5 kg·hm-2 sowing rate were 7 857.8 kg·hm-2 and 0.483, respectively. At heading and anthesis stages, less difference was noted in PAR between 30 cm and 40 cm row space treatments at the height of 20 cm above-ground of wheat plant. PAR values above 50 μmol·m-2·s-1 lasted at least 8 h in the 30 cm and 40 cm row space treatments. In white clover sole cropping, however, light compensation point was in the range of 30~50 μmol·m-2·s-1. It suggested that winter wheat-white clover intercropping with 30 cm or 40 cm wheat row space could met the requirement of effective light for photosynthesis in white clover. Another experiment with four treatments — two wheat varieties (“Xiaoyan 81” and “Jimai 22”) as sole crops and individual intercropping with white clover at 30 cm row space — were carried out. The results showed that “Xiaoyan 81” biomass was not affected by intercropping with white clover. Its’ LAI and ear density under intercropping were higher than those under monocropping. “Jimai 22” biomass, LAI and ear density under intercropping were lower than those under monocropping. Under intercropping, diurnal PAR variation at the top of white clover canopy exhibited a unimodal curve. Diurnal PAR at bottom of white clover canopy was less than 30 μmol·m-2·s-1. Diurnal PAR variation at the bottom of “Xiaoyan 81”-white clover intercropping system was smaller than that in “Jimai 22”-white clover intercropping system. In general, 30 cm row space of winter wheat was the most suitable for winter wheat-white clove intercropping. With respect to wheat variety, “Xiaoyan 81” performed better than “Jimai 22” under intercropping. This study had laid the basis for developing winter wheat-white clover intercropping systems in North China Plain.

     

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