Location: Columbia Plateau Conservation Research Center
Project Number: 2074-21600-001-007-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 1, 2023
End Date: Aug 30, 2025
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 flax cultivars 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.
Approach:
Alternatives to the traditional winter wheat-fallow crop production system will be evaluated in two trials: a fall-seeded cover crop trial and a flax variety trial.
Fall-seeded 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 (Starvation Farms, Morrow County, OR) and at an intermediate precipitation (<420-mm) research site (Columbia Basin Agricultural Research Center, Oregon State University, Umatilla County, OR). Cover crop treatments will include: winter canola, winter pea, winter barley, a three-species mix (winter canola, winter pea, winter barley), and fallow as a control. The research format 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, completing a dataset for four years and two site replications. The low precipitation site will be managed with vertical tillage and the intermediate site with no-till. Various measurements will be made to assess potential benefits and tradeoffs 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.
Flax variety trial: The trial will include 3-10 unique flax cultivars obtained from leading public and private breeding programs. The trial will be conducted in the intermediate precipitation region under dryland cropping and conventional tillage. The study will be a randomized complete block design with four replicates. Flax will be sown as a spring crop following winter wheat in a wheat-chemical fallow rotation. The trial will be initiated at a new location each year for the lifespan of agreement. Flax varieties will be evaluated for yield and oil content.
