Submitted to: Crop Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 31, 2011
Publication Date: March 28, 2011
Citation: Williams, J.D., Long, D.S. 2011. Intensive crop rotation yield and economic performance in minimum tillage and no-tillage, in northeastern Oregon. Crop Management. Available: http://plantmanagementnetwork.org/cm/element/sum2.aspx?id=9430 Interpretive Summary: The wheat growing region of the Pacific Northwest, USA, is divided into three precipitation zones, low, intermediate, and high. In the intermediate zone (15-18 in.), two-year rotations of winter wheat – fallow managed with traditional mechanical fallow remain popular in Northeastern Oregon. This system is costly in terms of labor and fuel, and contributes to environmental problems. An alternative is to increase the intensity of cropping with spring crops and convert to no-tillage management. No-tillage crop production resolves many of those problems, but specific disease and weed control problems can limit yields more under no-tillage than under conventional tillage. A four-year experiment was conducted to compare economic returns and annual yield variability intensive crop production in two weed management systems: (1) minimum tillage with cultivation by chiseling, sweeping, and rod weeding, and (2) no-tillage with chemical weed control. The production system was a four-year crop rotation, winter wheat -spring pea-winter wheat-fallow-fallow, in which a spring legume crop was included to aid in the control of weeds. All phases of the rotation, in both conventional tillage and no-tillage, were present each year. Wheat yields in the no-tillage treatment were equal to or better than those in the conventional tillage treatment. Economic analysis shows that no- tillage is significantly less costly than minimum tillage in terms of labor and fuel. No-tillage may be economically viable for intensive cropping systems in intermediate rainfall dryland regions of the Pacific Northwest.
Technical Abstract: In the intermediate precipitation zone (15-18 in.) of northeastern Oregon, there is interest in increasing the intensity of cropping with spring crops. Mechanical tillage remains popular for seedbed preparation and weed control, but contributes to environmental problems and labor and fuel are costly. No-tillage (NT) crop production resolves many of those problems, but disease and weed control problems can limit yields. We compared annual yield variability and economic returns of an intensive, four-year crop production rotation under two weed management systems: (1) minimum tillage (MT) with cultivation by chiseling, sweeping, and rod weeding, and (2) NT with chemical weed control. The rotation was winter wheat-spring pea-winter wheat-fallow [WW(f)-SP-WW(p)-F] in which a spring broadleaf crop is included to aid in the control of weeds. Wheat yields in the NT treatment were equal to or better than those in the MT treatment. Productivity differed significantly in each phase of the rotation in descending order from WW(f), WW(p), and to SP. Partial budget analysis shows that NT is substantially less costly than MT in terms of labor and fuel, potentially making NT economically viable for intensive cropping systems in intermediate rainfall dryland region of northeastern Oregon.