[Comparison of roots distribution in different maize plant type cultivars in the Songnen Plain]

By soil column culture and field experiment, the comparison of roots distribution of spreading-leaf and upright-leaf maize cultivars in the Songnen Plain was studied. The results showed that there were differences in the roots distribution of different maize cultivars. The maximum of root dry weight appeared on the 15th day and 30th day after silking for spreading-leaf and upright-leaf maize cultivar, respectively. Compared to spreading-leaf maize cultivar, the root dry weight of upright-leaf maize cultivar was higher by 12.2%. The vertical distribution of different maize cultivar roots was different. The root dry weight rate below 20 cm depth of spreading-leaf maize cultivar was less than 19%, whereas that of upright-leaf maize cultivar was more than 23%. Compared with spreading-leaf maize cultivar, the root dry weight rate at 40-100 cm depth was higher by 43.3%. There were differences between the different maize cultivars in the horizontal roots distribution. The roots of upright-leaf maize cultivar distributed tightly in horizon. The percentage of root dry weight of upright-leaf maize cultivar in a horizontal area 0-10 cm from the plant center was higher than that of spreading-leaf maize cultivar by 9.6%. Upright-leaf maize cultivar had more roots in deeper soil depth and it distributed tightly in horizon. Therefore, it was suitable for compact-planting. It was easier to acquire high yield for upright-leaf maize cultivar because it had good roots distribution characteristics.