摘要:为解决川中丘陵区机播质量差、季节性干旱频发危害玉米生长现象，本试验以该地区主推玉米品种‘正红505’为材料，采用裂区设计，通过田间及盆栽试验，研究不同种子大小及播种深度对玉米苗期、穗期根系生长及分布的影响，以期为本区域玉米的机械化精量播种和抗旱栽培提供理论依据。结果显示：1）种子越大发芽率越高；适当浅播（2~6 cm）能显著提高发芽率，2 cm较10 cm播深发芽率提高6.5%。2）大粒种子的根长、表面积、体积及干重极显著大于小粒种，虽然随生育进程推进，大、小粒种间根系生长的差异逐渐缩小，但至吐丝期，大粒种子的根长、表面积、体积及干重仍较小粒种分别高28.6%、25.0%、22.4%和11.4%。3）三叶期2 cm与6 cm播深的根系较10 cm播深下根长、表面积、体积及干重显著更高，但之后10 cm播深的根系生长更快，五叶期-七叶期后，超过2 cm播深的玉米；至吐丝期，10 cm播深玉米根长、表面积、体积和干重较2 cm浅播处理分别提高17.1%、11.9%、14.0%和10.4%，差异均达显著水平。4）种子大小对根系的分布影响较小，但播种深度对根系分布影响显著。10 cm深播较2 cm浅播处理可显著提高10 cm以下土层玉米根系的分布。5）种子越大，产量越高，大、中粒种子较小粒种子玉米产量分别提高9.1%和7.3%（P < 0.05）；适当深播（6~10 cm）能有效增加产量，6 cm、10 cm播深玉米产量较2 cm播深产量分别提高11.8%、26.3%。研究结果表明玉米大粒种子有利于建成发达的根系，适当深播有利于中、后期根系的生长和增加深层土壤的分布，从而提高玉米水肥吸收能力，提高其抗旱性，最终达到提高产量的目的。因此，川中丘陵区应选大中粒种并适当深播。
关键词:玉米/
种子大小/
播种深度/
根系发育/
根系分布
Abstract:Poorly executed mechanized seeding and frequent occurrence of seasonal drought in the hilly areas in middle Sichuan compresses the growth of maize. Using the main cultivar for this region, 'Zhenghong505', and adopting a split zone design with field and pot experiments, the effects of different kernel sizes and sowing depths on the growth and distribution of roots at the seeding and ear stages of maize were studied to provide a theoretical basis for mechanized precision sowing and drought-resistant cultivation of maize in this region. The results were as follows:1) Larger kernels and an appropriate shallow sowing depth (2-6 cm) can both significantly increase the germination rate. Compared with deep sowing (10 cm), the germination rate under shallow sowing (2 cm) increased by 6.5%. 2) The length, surface area, volume, and dry weight of roots arising from large kernels were significantly greater than those from small kernels. Although the differences in root growth gradually reduced with the growth process, the length, surface area, volume, and dry weight of the roots were still 28.6%, 25.0%, 22.4%, and 11.4% higher, respectively, than for small kernels at the silking stage. 3) At the 3-leaf stage, the root length, surface area, volume, and dry weight of roots arising from kernels planted at 2 cm and 6 cm were significantly higher than for those sowed at 10 cm depth, and these parameters for roots from kernels planted at 10 cm surpassed those for kernels planted at 2 cm by the 5-7-leaf stage. The length, surface area, volume, and dry weight of the roots arising from kernels planted at 10 cm at the silking stage were significantly higher (17.1%, 11.9%, 14.0%, and 10.4%, respectively) than those at the 2 cm sowing depth, and the roots in the 10-20 cm soil layer contributed to an increase in yield. 4) Kernel size had little effect on root distribution, but a sowing depth of 10 cm increased the root distribution rate in soil layers below 10 cm. 5) Yields from large and medium kernels were significantly higher (9.1% and 7.3%, respectively) than those from small kernels. Deep sowing effectively increased yields by 11.8% at 6 cm depth and 26.3% at 10 cm sowing depth compared with sowing at 2 cm. Large kernels were conducive to the establishment of well-developed roots, whereas sowing at an appropriate depth was conducive to the growth and downward distribution of roots in the middle and late stages, thereby increasing their water absorption capacity and drought resistance, ultimately achieving the increase in yield. Therefore, when planting maize, large and medium kernels should be selected and sown deeper appropriately.
Key words:Maize/
Kernel size/
Sowing depth/
Root development/
Root distribution
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