东北黑土区高产大豆R5期根系分布特征

利用钻土法及根系扫描分析系统研究不同产量类型大豆R5期根系在植株周围、株间及垄间土壤中的空间分布特征。结果表明：高产类型大豆根冠比较高，而且单位根长、根表面积的地上部干物质较高。根干重不仅在根系较集中的植株周围及株间0 ~ 30 cm的土层，而且在较深的土层（> 30 cm）中都有较多的分布；根长在植株周围的0 ~ 45 cm土层范围内表现出一定的优势。直径 < 1.0 mm的细根形成了根系的主要部分，根长差异的主要原因不是细根比例的大小，而是细根数量的多少。除株间0 ~ 15 cm土层外，高产大豆各土层的根/土体积比较高。

Characteristics of root distribution at R5 stage in high yielding soybean in black soil

Soil coring method and root analysis system,were used to investigate the vertical profiles of root system characteristics for the following positions including on plant,at plant spacing and row spacing,at R5 stage in soybean with different yield performance.The results showed that high-yielding soybean cultivar had strong ability of assimilation with high ratio of root to shoot,and resulted in more shoot dry weight per unit root length and root surface area.The characteristics of root in soil profile were: most roots distributed in both 0~30 cm of soil layer and deeper layer(>30 cm) at the positions of plant and plant spacing with high root dry weight.The fine roots with 0~1.0 mm of root diameter was the main part of root system,but the differences of root length between different yielding types was determined by the fine root amount.Except for the 0~15 cm of soil layer at plant spacing position,a higher root diameter and ratio of root volume to soil volume in soil profile was found in high-yielding soybean cultivar.