Sand transport and abrasion within simulated standing vegetation

Authors: GONZALES, HOWELL - Kansas State University; Casada, Mark; HAGEN, LAWRENCE - Retired ARS Employee; Tatarko, John; MAGHIRANG, RONALDO - Kansas State University

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/17/2017
Publication Date: 6/29/2017
Publication URL: http://handle.nal.usda.gov/10113/5922759
Citation: Gonzales, H.B., Casada, M.E., Hagen, L.J., Tatarko, J., Maghirang, R. 2017. Sand transport and abrasion within simulated standing vegetation. Transactions of the ASABE. 60(3):791-802. https://doi.org/10.13031/trans.11878.
DOI: https://doi.org/10.13031/trans.11878

Interpretive Summary: Wind erosion risk increases during spring and fall when reduced crop or residue cover is present for protecting the soil. This poses great risk to soils that, during these times, have only crop residues or young seedlings as cover for protection from erosion. Young plants that provide soil cover in spring are vulnerable to damage from abrasion by soil particles during wind erosion events. Only limited studies are available however, on the susceptibility of these plants to abrasion within a plant canopy. Sand transport and abrasion of artificial standing vegetation simulating young grass-type crops (e.g., wheat and corn) were studied in a wind tunnel and results compared to a study using young broadleaf crops like soybeans. Results showed that younger (shorter) wheat-like canopies are more susceptible to damage caused by sand blasting (i.e., abrasion) because the straw-like structure limits its ability to intercept moving, bouncing sand particles compared to young broad-leaved plants. The study also confirmed that wind speed alone does not cause the damage to crops during wind erosion events, but it’s the abrasive action of moving, bouncing particles that directly causes the damage. These results demonstrated the effects of height and plant configuration on damage by abrasion during wind erosion events. Results will also lead to additional wind flow studies to determine optimal height and configurations of other crops that best prevent damage by abrasion during wind erosion events.

Technical Abstract: Crop residues help protect topsoil from depletion and abrasion due to wind erosion. Limited studies have focused on type and orientation of canopies that help minimize effects of erosion by wind. In this study, a series of wind tunnel experiments was conducted to measure sand transport and abrasion energies within simulated standing vegetation. Wind speed profiles, relative abrasion energies, and rates of sand discharge were evaluated during 3-min test runs at two different vegetation heights (150 and 220 mm) for each of three densities of the simulated vegetation (i.e., 100 x 200 mm, 200 x 200 mm, and 300 x 200 mm spacing). Tests were also conducted for a bare sand surface. As expected, vegetation density was directly related to threshold velocity and inversely related to sand discharge. The densest configuration (i.e., 100 x 200 mm spacing) increased the threshold velocity of bare sand from 5.9 m s-1 to 10 m s-1. The presence of vegetation was found to be effective in minimizing abrasion experienced by the standing vegetation models by lowering the saltation of sand particles that could impact the simulated plants. The coefficient of abrasion, a measure of kinetic energy via the impact of saltating particles, was adversely affected by saltation discharge, although this did not depend on wind speed. The values of the coefficient of abrasion for all types of configuration was significantly different (p < 0.05) from the bare sand state.