Using dye tracer for visualizing roots impact on soil structure and soil porous system

Abstract

AbstractPlants influence the water regime in soil by both water uptake and an uneven distribution of water infiltration at the soil surface. The latter process is more poorly studied, but it is well known that roots modify soil structure by enhancing aggregation and biopore production. This study used a dye tracer to visualize the impact of plants on water flow in the topsoil of a Greyic Phaeozem. Brilliant blue was ponded to 10 cm height in a 1 m × 1 m frame in the field immediately after harvest of winter wheat (Triticum aestivum L.). After complete infiltration, the staining patterns within the vertical and horizontal field-scale sections were studied. In addition, soil thin sections were made and micromorphological images were used to study soil structure and dye distribution at the microscale. The field-scale sections clearly documented uneven dye penetration into the soil surface, which was influenced by plant presence and in some cases by mechanical compaction of the soil surface. The micromorphological images showed that root activities compress soil and increases the bulk density near the roots (which could be also result of root water uptake and consequent soil adhesion). On the other hand in few cases a preferential flow along the roots was observed.