ABSTRACT
Plant roots influence such physical properties as structure stability, bulk density, porosity, soil mineralogical and mechanical composition, water and ion characteristics of soil, and also biological activity of the soil. The role of plant roots in soil structure formation consists generally in soil aggregation. Roots and root hairs penetrating the soil produce lines of weakness along which the clod or soil mass may break into granules. The effect of living roots on soil structure stability, apart from the nature of the mineral substrates and climatic conditions, depends on the plant species. H. Kobayashi and Y. Otake, studying the effect of the growth of forage (timothy) and upland rice root systems on soil porosity, stated that the total soil porosity in the grass plot was less than in the rice plot, but effective soil pores in the forage plot were more abundant than in the rice plot.
