Modeling Multirow Wind Barrier Density

ABSTRACT:

Field multirow wind reduction patterns can be expressed with a Barrier Effectiveness Index (BEI), but this index cannot be used to model wind barrier effects on wind erosion. The effect of barrier density on wind passing through the barrier must be described to model wind barriers. The drag effect of the wind passing through field barriers was simulated in a laboratory wind tunnel. Total drag in the wind tunnel was measured for simulated barriers with various row number-spacings-densities and the drag was correlated with BEI (r² = 0.84). This empirical relationship permitted the development of the Equivalent Optical Density (EOD) from optical density (OD) of each row (N), barrier height (H) and spacing between rows (RS).

EOD values were computed and correlated to total drag values. The relationship was then tested on additional barriers, and the resulting overall correlation (r² = 0.92) was significant. Using the EOD equation, the wind barrier effects were computed for one to eight row (N) barriers, five optical densities, and three spacings between rows. EOD can be used to compute wind reduction patterns for the Revised Wind Erosion Equation (RWEQ) model. This permits the design of a wind barrier system (number of rows and plant density within each row) that will be most effective in reducing wind erosion for the farmer.