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ARS Home » Pacific West Area » Pendleton, Oregon » Soil and Water Conservation Research » Research » Publications at this Location » Publication #313054

Research Project: Improved Soil Managment Practices for Tilled Summer Fallow in the Pacific Northwest

Location: Soil and Water Conservation Research

Title: Soil water and water use efficiency in no-tillage and sweep tillage winter wheat production in northeastern Oregon

Author
item Williams, John
item Wuest, Stewart
item Robertson, David - Dave

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/23/2015
Publication Date: 7/24/2015
Citation: Williams, J.D., Wuest, S.B., Robertson, D.S. 2015. Soil water and water use efficiency in no-tillage and sweep tillage winter wheat production in northeastern Oregon. Soil Science Society of America Journal. doi: 10.2136/sssaj2014.12.0494.

Interpretive Summary: The productivity of rainfed winter wheat depends on the efficient capture and storage of precipitation. In the semi-arid Pacific Northwest, U.S.A., soil water is managed through a fourteen-month fallow period in order to establish wheat before winter and maximize growth potential the following spring. The effects of residue and soil management on soil water storage were investigated at site near Pendleton, Oregon. Rainfall capture, storage, and use was measured in winter wheat grown every year using no-tillage, and for 10 months followed by 14 months of either chemical fallow or a low-soil-disturbance (undercutter) fallow. Measured from 2007 through 2014, the two year chemical fallow had significantly more soil water than the undercutter fallow. Winter wheat grown annually used less soil water and produced more wheat than the two year rotations. There was no yield difference between the crops grown under chemical or undercut fallow. Thus, water use efficiency was 30% greater in annually grown wheat than the two year rotation wheat. Unlike reports from drier zones of the Pacific Northwest, it appears that chemical fallow and annual wheat production are the best for maximum efficiency of water use by wheat.

Technical Abstract: The productivity of rainfed winter wheat (WW, Triticum aestivum L.) depends on the efficient capture and storage of precipitation. In the semi-arid Pacific Northwest, U.S.A., soil water is managed through a fourteen-month fallow period in order to establish wheat before winter and maximize growth potential the following spring. The effects of soil management on soil water storage were investigated on a Walla Walla silt loam soil, (coarse-silty, mixed, superactive, mesic Typic Haploxerolls). The treatments were untilled chemical fallow (CF), versus a one-pass undercutter fallow (UF) in two-year WW-fallow rotations. These were compared to an annually cropped no-till WW (ANT). Measured from 2007 through 2014, CF had significantly more soil water than UF. ANT always had less soil water than CF or UF. These results were not reflected in precipitation capture efficiency. Annualized crop yield was significantly greater in ANT than in CF or UF, which were not significantly different. This resulted in water use efficiency being 30% greater in ANT than CF or UF. Unlike reports from drier zones of the Pacific Northwest, it appears that CF and even annual wheat production may be ways to maximize efficiency of water use by wheat.