Comparative performance of forage sorghum, grain sorghum, kenaf, switchgrass, and slat-fence windbarriers in reducing wind velocity

Windbarriers used to control wind erosion may be woody or herbaceous, annual or perennial; or they can be “artificial.” To properly space windbarriers, the velocity-reduction characteristics of the windbarrier must be known. Velocity reduction curves for windbarriers of grain and forage sorghum [Sorghum bicolor (L.) Moench], kenaf (Hibiscus cannabinus L.), switchgrass (Panicum virgatum L.), and slat-fences were developed from field measurements. The number of rows in the respective windbarriers and their percent of upwind velocity (the lower the percent the better) at 10 m (32.8 ft) downwind [at 20 cm (8 in) height] were: switch-grass (one row, 39%), slat-fence (two rows, 43%), slat-fence (one row, 48%), grain sorghum (three rows, 60%), kenaf (eight rows, 69%), forage sorghum (four rows, 76%), kenaf (six rows, 78%), and kenaf (four rows, 79%). These and other presented data should be useful in designing windbarrier systems or modeling their effects on downwind velocities.