Effects of different management systems on root distribution of maize

Characterization of root distribution in maize (Zea mays L.) is important for optimizing agronomic management to match crop requirements, while maximizing grain yield, especially under intensive management. The objectives of this study were to examine the differences in maize root distribution between two management systems and to identify root-related factors that could be adjusted for further yield improvement. A 4-yr field experiment examined maize root distribution under two management systems: farmers' practices (FP: low plant density, unbalanced fertilization) and high yield strategies (HY: high plant density, sufficient fertilization). Root mass distribution within the soil profile was more restricted horizontally within 10 cm from the stalk base and vertically below 20 cm in HY compared with FP. HY had a greater proportion of fine roots (diameter <= 0.5 mm) and more roots per 100 kernels than FP. However, per-plant root weight was not significantly affected by type of management system. Yield was positively correlated with total root number and the ratio of root mass below 20 cm to total root mass. Our data indicate that HY maize overcame the negative effect of crowding stress by producing more roots with smaller root diameters, and maize root systems became narrower and were distributed deeper under intensive management compared with traditional famers' practices.