Submitted to: Joint Federal Interagency Sedimentation and Hydrologic Modeling
Publication Type: Proceedings
Publication Acceptance Date: 9/2/2009
Publication Date: 7/1/2010
Citation: Williams, J.D., Robertson, D.S., Wuest, S.B. 2010. Upland Drainage Response to No-till Winter Wheat Production. In proceedings of the 2nd Joint Federal Interagency Conference - 4th Federal Interagency Hydrologic Modeling Conference and of the 9th Federal Interagency Sedimentation Conference, June 27-July 1, 2010, Las Vegas, NV. On CD.
Technical Abstract: Conventional tillage practices, combined with a two year winter wheat-fallow rotation, have long been identified as substantial sources of sediment in the interior Pacific Northwest (PNW). No-tillage crop production has been shown to be an effective means of reducing run-off and erosion in a wide variety of environments and cropping systems, but not at commercial scales in the PNW. Our objective was to compare runoff and soil erosion from a conventional tillage, wheat-fallow two-year rotation and a no-tillage four-year rotation within a small watershed to provide results that would be representative of conservation effectiveness at the field scale. Two neighboring drainages, 5.8 ha and 10.7 ha, in the 340 mm y-1 precipitation zone of northeastern Oregon, were instrumented to record rainfall, runoff, and erosion over a four-year period (2001 through 2004). In addition to drainage scale monitoring, small 1 m-1 runoff collectors were installed within the drainages to capture hillslope soil and water movement during 2003 and 2004. One drainage was cropped to a winter wheat–fallow rotation using conventional inversion tillage (tillage fallow). The second drainage was cropped in a four-year no-tillage rotation: winter wheat–chemical fallow–winter wheat–chickpea. We recorded 13 runoff events from the inversion tillage system and 3 from the no-till system. Annual runoff and erosion from inversion tillage drainage were 1.3 mm and 0.07 Mg ha-1 versus 0.1 mm and <0.01 Mg ha-1 from no-tillage drainage. There was substantially more runoff and soil movement at the small plot scale, 79 mm y-1 and 11.01 Mg ha-1 y-1 from the conventional tillage treatment and 23 mm y-1 and 0.21 Mg ha-1y-1 from the no-tillage treatment. Soil erosion observed in this research is a fraction of that reported for similar tillage practices outside of the PNW. The no-tillage cropping system was more effective in reducing runoff and soil erosion and provides producers with an ability to protect soil and water resources in the dryland PNW.