为阐明冠层与根系对不同生长空间竞争的响应,进一步明确扬黄灌区合理空间布局的增产机理,以先玉335为试验材料,设置2个种植密度(低密度：7.50万株 hm-2、高密度：9.75万株 hm-2),2个行距配置(等行：60-60cm、宽窄行：40-80cm),比较株行配置对春玉米冠层和根系结构与功能及产量的影响。结果表明,随种植密度增加,果穗、茎鞘干重百分比垂直分布明显上移,而叶片干重百分比在垂直分布变化较小,行距配置对果穗、茎鞘干重百分比在垂直分布上影响较小,相对于等行种植,宽窄行种植叶片干重百分比有下移趋势,群体不同叶位叶面积指数也表现为同一密度下,宽窄行种植群体上层LAI较小,穗位叶高效叶层LAI较大；随密度增加,根重有纵向下移的趋势,根系TTC还原强度在不同土层深度都显著降低,同一密度下,宽窄行种植根重的垂直分布出现下移趋势,根系TTC 还原强度略高于等行种植；中密条件下宽窄行种植降低了玉米果穗秃尖长,显著增加了果穗穗粒数,因而显著提高产量,增产2.73%~10.86%,由此说明,在宁夏扬黄灌区较高种植密度下,采用宽窄行种植能优化不同叶层结构,适当增加深层土壤根系所占比例及活力,有利于获得高产。
英文摘要:
The objective of this study is to evaluate the impact of planting density and row spacing on root-shoot spatial distribution and grain yield of spring maize, uncover the mechanism of increase production and yield under rational space arrangements. In this research, the cultivar “Xianyu335” was applied as research material. Two densities (7.50×104 and 9.75×104 plants?hm-2) and two row spacings(equidistant row:60-60cm, twin-row: 40-80cm) were designed to explore the effects of planting density and row spacing on canopy Structure, root distribution and function and yield. The results showed that vertical distribution of percentage of dry matter weight of stem, sheath and ear increased with the increase of planting density, however, there had been little change in the percentage of dry weight of the leaf. Row spacing had little effect on percentage of dry matter weight of stem, sheath and ear in the vertical distribution, Compared with equidistant spacing planting, vertical distribution of canopy resulted in a trend that the percentage of dry weight of the leaf decreased, the performance characteristics of LAI were upper ones smaller and high effective leaf larger with twin-row planting. There was a downward trend in the root weight with the increase of plant density, the root TTC reductive intensities was significantly decreased at different soil depth. Within the same density stand, the vertical distribution of root weight with twin-row planting in various soil layers tended to go down, meanwhile, the root TTC reductive intensities with twin-row planting slightly higher than that of equidistant spacing planting. The results indicated that reasonable planting density and twin-row planting increased grain yield of maize significantly by 2.73% to 10.86% due to reduction barren ear tip and enhancement of grains per spike. The results of this study suggest that maize grown in twin-row planting with rational density will provide optimal canopy structure, root distribution and TTC activity in deep soils that may promote maize yield in new irrigated region with water pumped from the Yellow River in Ningxia.
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