Soil Erosion Resistance-enlarging Potential by Plant Roots as Determined in a Simulated Flume Experiment

It has been suggested in previous studies that plant roots enlarged soil resistance to concentrated flow erosion mainly through physical (root net-link and root-soil bonding) and biochemical effects. The objective of this study is to further assess soil resistance-enlarging potential of this twofold effect of roots, especially for different textured soils. Two textured soils (silt loam and silt clay) and four kinds of soil samples (1. bared parent soils, representing samples with no root effect, 2. bared tillage soils, representing samples with biochemical effect alone, 3. root-texture cotton thread-permeated soils, representing samples with root net-link effect alone and 4. Purple alfalfa root-permeated soils, representing samples with root total effect.) were prepared and tested in flume experiments. The results showed that soil resistance to concentrated flow increased and sediment yields decreased in different degrees due to different root effects. Root physical effect increased soil resistance to a larger extent compared with root biochemical effect (the relative contribution values of root physical effect were 85% and 89% in silt loam and silt clay soil, respectively). In root physical effect, root soil bonding appeared to act as the main form, particularly in silt clay.