Plant-induced Changes in Soil Structure: Processes and Feedbacks

Soil structure influences the growth and activity of organisms living in soil. In return, microbes, fauna, and plants affect structure. The objective of this paper is to review the role of plants in modifying soil structure. Vegetation affects structural form and stability at different scales and through various direct and indirect mechanisms. By penetrating the soil, roots form macropores which favour fluid transport. They also create zones of failure which contribute to fragment the soil and form aggregates. This phenomenon is enhanced by the wetting and drying cycles associated with plant growth. Drying also causes shrinkage and strengthening of the soil. Anchorage of roots and the exudation of cementing material stabilizes soil structure. Finally, as a source of C, roots and plant residues provide a food source to the microflora and fauna which contribute to structure formation and stabilization. In return, plant-induced changes in structure will affect plant growth mostly by modifying the root physical environment, and the water and nutrient cycles.