Effects of artificial root-pores on maize roots growth in compacted soil using X-ray computed tomography

Compaction is one of the main types of soil degradation worldwide. The macropores left by ex-plant roots were expected to provide channels to root to penetrate hard soil layers. However, there are few studies to quantitate the relationship between the elongation of maize roots and the root pores, due to complex morphological characteristics of the real root pore systems. In this study, we tried to build an artificial pore with sheath to simulate the effects of root pores on maize root growth in the compacted soil by X-ray CT. Our results indicated that the method for simulating root pores worked well. The sheath width of artificial root-pore was about 2.69 mm. Moreover, sheath of pores had higher organic carbon content and abundance of actinobacteria compared with bulk soil. Compared with artificial macropores, the presence of artificial root-pores diminished the border effects of the pot wall and increased the growth angle of node1 roots and the maximum growth depth of maize roots. However, there were no significant differences in terms of roots spatial distribution (in soil matrix, macropore sheath, macropore), and the ways (crossing or colonizing) of utilization by maize roots to macropores between the treatments with artificial macropores and artificial root-pores. This study provides a new insight into the interactions between root pore, root-pore sheath and maize roots.