|Bilbro, James - RETIRED USDA-ARS|
Submitted to: International Soil Conservation Organization Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 24, 1999
Publication Date: N/A
Interpretive Summary: Preliminary experiments at a West Texas lab in the heart of Dust Bowl country suggest wind erosion reduces crop yields. In some mini-Dust Bowl experiments, ARS scientists planted crops on land that had been left bare and exposed to the wind for the previous 9 years. Yields of these crops were 40 to 65 percent lower. The results are preliminary data from 1997 and 1998--the first two years of growing crops on the eroded plots. Average annual yield reductions were 65 percent for forage sorghum, 58 percent for grain sorghum and 40 percent for cotton and kenaf. The comparison are to crops grown on soil that was not allowed to erode, using tillage techniques and crop residue to cover the soil. During the 9 years of wind exposure, the eroded land had lost 590 tons of soil an acre. In other words, the wind shaved off about 10 inches of topsoil. Possible reasons for the severity of the yield losses include lower fertility for the eroded area and a loss in water-holding capacity for the eroded soil. The scientists found that wind erosion selectively removed phosphorus, an important crop nutrient. Phosphorus levels were about 35 percent lower on the eroded soil compared with the non-eroded area. The 590-tons-per-acre soil loss did not affect the texture of the topsoil. Eventually, with more wind erosion it might, however, as the deep topsoil wears down to a clay layer that would interfere with crop roots and further threaten yields.
Technical Abstract: Wind erosion degrades soil quality by modifying soil properties important for optimum plant growth and productivity. In this study we evaluated soil properties and plant productivity of an Amarillo fine sandy loam soil that had been severely wind-eroded for 9 years, causing a loss of about 10 cm (over 1300 mt ha-1) of the soil surface. Cotton, kenaf, and grain and forage sorghum were grown for two years and soil tests were performed on eroded, deposited, and non-eroded areas. The eroded areas produced 34 percent lower cotton boll weights and 40 percent lower lint weights than the non-eroded areas in 1998. Cotton lint yields were not significantly different (P<0.10) in 1997, probably due to severe insect damage. The grain yield of grain sorghum was an average (over the 2 years) of about 57.5 lower in the eroded area than the non-eroded area. The forage sorghum grain yield in 1998 was 83 percent lower on the eroded area than the non-eroded area. The kenaf yield was an average of about 40 percent lower on the eroded area than the non-eroded area. Erosion had significantly increased (P<0.05) sand content on the deposited area but caused little textural change in the surface of the eroded area compared with the adjacent non-eroded site. The eroded area had significantly less phosphorus, as measured by Bray P1 and P2 methods, than the adjacent non-eroded area. Few differences were found for other plant nutrients among the sites.