Abstract
Macropores influence the movement of water and air in the soil significantly. A study was conducted to investigate the characteristics to determine the water and air movement functions of tubular-pores which originated from plant roots. The results were as follows:
1. The smallest macropore had 50μ m diameter, where water drained at pF 1.8 from the viewpoint of soil pore structure.
2. Horizontal hydraulic conductivity was larger than vertical in most of the layers since large tubular-pores (diameter: 1-2 mm) were mainly in the horizontal direction. It was noted that large tubular-pores had high tortuosity and small tubular-pores (diameter: 50-300μm) connected with large pores.
3. It is suggested that there are some differences between the routes for water and air movement. The difference may be due to the complicated network of tubular-pores.
4. We can classify the soil samples to four types by the structure of entry pores which are estimated by the drainage curve from entry-pore experiment and radiographs using soft X-ray. Tubular-pores of varying diameter connect together to make the entry-pores in soil.
