Title: Soil Property Effects on Wind Erosion of Organic Soils Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 7, 2011
Publication Date: September 21, 2011
Citation: Zobeck, T.M., Baddock, M.C., Van Pelt, R.S., Tatarko, J., Acosta Martinez, V. 2011. Soil Property Effects on Wind Erosion of Organic Soils[abstract]. International Symposium on Erosion and Landscape Evolution. September 18-21, 2011, Anchorage, Alaska. Technical Abstract: Histosols (also known as organic soils, mucks, or peats) are soils that are dominated by organic matter (>20%) in half or more of the upper 80 cm. Forty four states have a total of 21 million ha of histosols in the United States. These soils, when intensively cropped, are subject to wind erosion resulting in loss in crop productivity and degradation of soil, air, and water quality. Estimating wind erosion on Histosols has been determined by USDA-Natural Resources Conservation Service (NRCS) as a critical need for the Wind Erosion Prediction System (WEPS) model. WEPS has been developed to simulate wind erosion on agricultural land in the US, including soils with organic soil material surfaces. However, additional field measurements are needed to calibrate and validate estimates of wind erosion of organic soils using WEPS. A field portable wind tunnel was used to generate suspended sediment and dust from agricultural surfaces for soils ranging from 12% to 67% organic matter. The wind erodible fraction (<0.84 mm) and dry mechanical stability, as measured using a rotary sieve, ranged from 24% to 81% and 46% to 95%, respectively. The soils were tilled and rolled to provide a consolidated, friable surface. Dust emissions and saltation were measured using an isokinetic vertical slot sampler aspirated by a regulated suction source. Suspended dust was collected on filters of the dust slot sampler and sampled at a frequency of once every six seconds in the suction duct using a Grimm optical particle concentration and size analyzer. We also collected samples using a passive Wilson and Cooke sampling cluster as a backup data source. In addition, bulk samples of airborne dust were collected using a sampler specifically designed to collect larger dust samples. The larger dust samples were analyzed for physical, chemical, and microbiological properties. Particle density of the saltation-sized material (>106 microns) varied with organic matter (OM) content and ranged from 2.41 g cm-3 for the soil with the lowest OM content to 1.61 g cm-3 for the soil with highest OM content. The lowest OM soils produced the highest dust concentrations both during initial blow-offs and when abraded. The soil with the lowest non-erodible fraction (26%) had distinctly higher dust emissions compared with the other soils (non-erodible fraction >49%). The dust emissions from the four high OM soils (>25%) were not significantly increased by the introduction of abrader. Microbiological analysis shows enzyme activity (EA) in the sediment lost from plots as saltation and suspension was greater than the bulk soil. For example, ß-Glucosidase activity (EA) in the sediment removed by saltation was enriched by a ratio of 2.4 for the soil with the lowest OM content and by 1.4 for highest OM content soil, compared to the parent soil. For the suspended dust load EA analysis, enrichment ratios were 2.4 and 1.5 for the dust and parent soil, respectively. These results demonstrate the following: 1) Variations in dust emissions can be linked to soil properties; 2) Surface soil organic matter content affected wind erodibility and dust emissions; 3) Abrasion did not significantly increase dust emission rates from high OM soils due to their high mechanical stability; 4) The relative enrichment of EA in eroded sediment compared with the parent soil demonstrates soil degradation due to wind erosion with negative implications for soil sustainability.