Distribution of roots and root length density in a maize/soybean strip intercropping system

In a field experiment in the Yellow River Basin conducted in 2007 and 2008, it was found that, under full irrigation, the roots of maize not only penetrated deeper than those of soybean but also extended into soybean stands underneath the space between inner rows of soybean. The roots of soybean, however, were confined mainly to the zone near the plants. Horizontal growth of the roots of both the crops was confined mainly to the soil layer 16–22 cm below the surface, a layer that lay above an existing plough pan. Root length density (RLD) was much higher in the top layer (0–30 cm deep) and in the zone closer to the plants. The exponential model proved suitable to describe the RLD vertically and horizontally in both sole cropping and in intercropping.

Research highlights▶ This study raises an interesting point in the field of plant competition for soil resources in the particular case of intercropped maize and soybean. ▶ It presents a two years experiment focused on the description of root systems distribution inside different intercropping treatments. ▶ The authors combine different methods for the description of root systems (root maps and root length density) and test the suitability of exponential models to fit the rooting patterns.