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Can biosolids reduce wind erosion of agricultural soils?

Brenton Sharratt 1, William Schillinger2, Andrew Bary2, Craig Cogger0
1USDA-ARS, Pullman, WA, USA, 2Washington State University, Pullman, WA, USA

 

The application of biosolids to agricultural land has the potential to improve soil health and crop production. In addition, organic material contained in biosolids may enhance biological activity, retention of soil water, and soil aggregation. Thus, there is a likelihood that biosolids applied to soil could reduce the threat of wind erosion. The objective of this study was to assess the impact of biosolids on wind erosion of agricultural land in the Columbia Plateau of the Pacific Northwest United States. Synthetic fertilizer and biosolids were applied to a loess silt loam in the spring (April) during the fallow phase of a winter wheat - summer fallow rotation. The experimental design was split plot with the application of fertilizer and biosolids as main plot treatments and conventional and conservation tillage as subplot treatments. Wind erosion potential was assessed after the first rodweeding (mid-June) using a portable wind tunnel. An isokinetic sampler was used to measure horizontal sediment flux from 0 to 0.75 m above the soil surface inside the tunnel. Sediment flux was measured at a free-stream velocity of 16 m s-1 for 10 minutes with little saltation activity and a subsequent seven minutes with copious saltation activity. After the first rodweeding, horizontal sediment flux was greater for conventional (2597 and 1789 g m-1) than conservation (1447 and 770 g m-1) tillage during respectively periods of little saltation and copious saltation activity. Differences in sediment flux were not found between fertilizer and biosolids treatments. Preliminary results suggest that biosolids may not affect the wind erosion potential of loessial agricultural soils.