|FENG, GUANGLONG - Washington State University|
Submitted to: Soil and Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/29/2010
Publication Date: 1/1/2011
Citation: Feng, G., Sharratt, B.S., Young, F.L. 2011. Soil properties governing soil erosion affected by cropping systems in the U.S. Pacific Northwest. Soil and Tillage Research. 111:168–174.
Interpretive Summary: Winter wheat – summer fallow has long been the most profitable crop rotation utilized by farmers in the drier areas of the inland Pacific Northwest. However, wind erosion from land in summer fallow often contributes to poor air quality in the region. No-tillage spring cereal cropping systems are being considered as an alternative to the traditional winter wheat – summer fallow rotation to control erosion. We found that no-tillage spring wheat – spring barley and no-tillage spring wheat – chemical fallow rotations were less conducive to wind erosion than the traditional rotation. The soil surface of no-tillage rotations had more crop residue and moisture than the soil surface of the winter wheat – summer fallow rotation during the times of the year when winds cause erosion. Communities throughout the inland Pacific Northwest will comply with USEPA air quality standards if these rotations are adopted by farmers in the drier areas of the region; however, scientists must develop methods of successfully growing spring cereals that are as productive as winter cereals.
Technical Abstract: In the low-precipitation zone (<300 mm annual precipitation) of the inland US Pacific Northwest, no-tillage spring cereal rotations are being examined as alternatives to the traditional winter wheat - summer fallow rotation to control wind erosion. There is limited information, however, regarding the effects of no-tillage cropping systems on soil physical properties and surface characteristics that govern wind erosion in this semiarid region. The objective of this research was to characterize soil aggregates, moisture, strength, roughness, crusting, and crop residue cover and biomass of a silt loam that had been subject to various crop rotations for 11 years in east-central Washington. Crop rotations examined included no-tillage spring barley - spring wheat (NTSB/SW), no-tillage spring wheat - chemical fallow (NTSW/CF), and winter wheat - summer fallow (WW/SF). Soil physical properties were measured in spring 2006 after sowing wheat in the NTSB/SW rotation and in late summer 2006 after sowing winter wheat in the WW/SF and NTSW/CF rotations. In spring, the NTSB/SW and NTSW/CF rotations were characterized by a moister soil as compared with the WW/SF rotation. In late summer, the NTSB/SW rotation was characterized by a soil surface with more standing stubble and greater crust cover and soil strength as compared with the WW/SF and NTSW/CF rotations. Our results suggest that spring-sown cereal and chemical fallow cropping systems result in moister soils in spring and retain more surface residue in the late summer that will reduce the risk for wind erosion as compared with the traditional WW/SF rotation in the Pacific Northwest.