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.