Location: Columbia Plateau Conservation Research Center
Project Number: 2074-21600-001-012-A
Project Type: Cooperative Agreement
Start Date: Sep 1, 2025
End Date: Aug 31, 2026
Objective:
Evaluate alternatives to the two-year winter wheat-fallow system that reduce fallow periods in the dryland Pacific Northwest. Determine the potential for fall-seeded cover cropped systems to increase grain productivity and profitability through reductions in nitrogen inputs, enhancement to soil water infiltration and storage, and suppression of disease. Assess the performance of alternative crops (e.g. legumes, oil seed crops) as an alternative crop to winter wheat in the intermediate precipitation region. Provide resources, reports, extension education, and scientific publications so producers can make data-driven decisions on novel techniques to improve their dryland winter wheat production systems. Additionally, this project will support spring wheat breeding and end-use quality testing of early generation novel germplasm.
Approach:
Alternatives to the traditional winter wheat-fallow crop production system will be evaluated in two trials: a fall-seeded cover crops trial and alternative crop variety trials.
Winter cover crop study: The winter wheat-chemical fallow system will be modified by replacing fallow with fall-sown/spring terminated cover crops at a low precipitation (<250 mm) research site and at an intermediate precipitation (<420-mm) research site. Cover crop treatments will include: winter canola, winter pea, winter barley, a three-species mix (winter canola, winter pea, winter barley), and fallow control. It will be a systems trial arranged in a randomized split-plot design in which winter wheat and cover crops will be rotated for two complete cropping cycles at both sites (both crop phases present each year). The trial will be initiated in fall 2023 with the last harvest in fall 2027. Various measurements will be made to assess the impacts of the cover crop system, including in the areas of soil chemistry, microbiology, pathology, weeds, soil hydrology, crop physiology, and agronomy. Winter wheat performance following the five treatments will be evaluated. Measurements of weed seed bank, soil fertility, and soil moisture, will be evaluated across the lifespan of the study. Soil enzyme activity and molecular plant pathology will be evaluated in the winter wheat cash crop following cover crop and control treatments. Cover crop biomass, plant population, legume nitrogen fixation, and weed biomass will be evaluated. UAS data collection will be used, when possible, in combination with traditional manual methods. Winter wheat cash crop following cover crop treatments will be evaluated for yield, protein, test weight, and yield components. Weeds in the cash crop, canopy density, and soil temperature will be evaluated with UAS procedures. System economics will be evaluated.
Alternative crop variety trials: The trials will evaluate varieties (n=3-10 cultivars) of the most promising alternative crops obtained from leading public and private breeding programs. Decisions of yearly focus crop will be made between OSU and ARS agreement leadership. The crops could include legumes (e.g., soybean, lupin) or oilseed crops (e.g., camelina). The trials will be conducted in the intermediate precipitation region under dryland cropping and conventional tillage using a randomized complete block design with four replicates. A trial will be initiated each year for the lifespan of agreement. Oil seed crop varieties will be evaluated for yield and oil content. Legumes will be evaluated for yield and protein.
Spring wheat breeding: To support spring wheat breeding and end-use quality testing of early and advanced generation novel germplasm, 50-70 lines of early and advanced generation materials will be grown in the field. The trials will be conducted in the intermediate precipitation region under dryland cropping and conventional tillage. Selections of germplasm material will be made on the pillars of yield, end use quality, and disease resistance. Winter activities will include crossing, greenhouse advances, and collaboration with the Western Wheat Quality Lab.