Resilient Dryland Farming Alliance, 2021 – 2022 annual report: Alternative crop trial

Authors: SINGH, SURRENDRA - Oregon State University; Adams, Curtis; BARROSO, JUDIT - Oregon State University; CALDERON, FRANCISCO - Oregon State University; GOURLIE, JENNIFER - Oregon State University; GRAEBNER, RYAN - Oregon State University; HARRISON, KYLE - Oregon State University; HUNT, MATTHEW - Oregon State University; KRIETE, LINNEA - Oregon State University; LARSON, DAVID - Oregon State University; MACHADO, PEDRO - Embrapa; McGee, Rebecca; NAMDAR, GRAYSON - Oregon State University; PRITCHET, LARRY - Oregon State University; Reardon, Catherine - Kate; Umbarger, Stephen - Steve; WOOD, DAISY - Oregon State University; HAGERTY, CHRISTINA - Oregon State University

Submitted to: Extension Service Bulletins
Publication Type: Popular Publication
Publication Acceptance Date: 10/12/2022
Publication Date: 10/13/2022
Citation: Singh, S., Adams, C.B., Barroso, J., Calderon, F., Gourlie, J., Graebner, R., Harrison, K., Hunt, M., Kriete, L., Larson, D., Machado, P., Mcgee, R.J., Namdar, G., Pritchet, L., Reardon, C.L., Umbarger, S.K., Wood, D., Hagerty, C. 2022. Resilient Dryland Farming Alliance, 2021 – 2022 annual report: Cover crop trial. Extension Service Bulletins. Article 12596. https://extension.oregonstate.edu/sites/default/files/documents/12596/rdfa-cover-crop-report-2022-final.pdf

Interpretive Summary: Annual precipitation of only 8 to 16 inches led to large scale adoption of wheat-fallow systems (WF) to recharge moisture for the next year’s wheat crop in the eastern Oregon region. While beneficial for water storage, the fallow period is associated with negative impacts on soil erosion and soil carbon as compared to perennial or annual cropping systems. Alternatives to the WF production system are needed to enhance the soil health, resilience, profitability, and sustainability of dryland wheat operations. We conducted research to explore alternative crops to the winter wheat cash crop, this research is also an exploration of cropping intensification in the inland Pacific Northwest. The research was conducted at two locations: an intermediate rainfall site in Umatilla County (16 inches annual precipitation) and a low rainfall site in Morrow County (9 inches annual precipitation). At the intermediate rainfall site, alternative crop treatments replaced the typical fallow period. At the low rainfall location, alternative crop treatments followed a three-year rotation of winter wheat-alternative crops-fallow instead of the typical winter wheat-fallow system. The Resilient Dryland Farming Alliance (RDFA) is a product of a farmer-led initiative. The RDFA is evaluating intensified wheat-based systems to integrate alternative crops in order to reduce the number of fallow periods, to enhance soil health, break cycles of disease, decrease fertilizer requirements, and change or reduce herbicide inputs. This report includes preliminary data for the second year of a three-year study. Data showed that winter pea and brown mustard produced the greatest amount of biomass of the alternative crops tested at both sites. Weed biomass was lowest under winter pea treatments at both sites. Brown mustard and flax both had higher yields at the Umatilla County site compared to the Morrow County site. Despite producing higher biomass and considerable yields, residual moisture under brown mustard was similar to fallow moisture in topsoils and was similar to other alternative crops at deeper depths. Due to a historic drought in crop year 2020-2021, biomass produced by many of the alternative crops was lower than expected.

Technical Abstract: Annual precipitation of only 8 to 16 inches led to large scale adoption of wheat-fallow systems (WF) to recharge moisture for the next year’s wheat crop in the eastern Oregon region. While beneficial for water storage, the fallow period is associated with negative impacts on soil erosion and soil carbon as compared to perennial or annual cropping systems. Alternatives to the WF production system are needed to enhance the soil health, resilience, profitability, and sustainability of dryland wheat operations. We conducted research to explore alternative crops to the winter wheat cash crop, this research is also an exploration of cropping intensification in the inland Pacific Northwest. The research was conducted at two locations: an intermediate rainfall site in Umatilla County (16 inches annual precipitation) and a low rainfall site in Morrow County (9 inches annual precipitation). At the intermediate rainfall site, alternative crop treatments replaced the typical fallow period. At the low rainfall location, alternative crop treatments followed a three-year rotation of winter wheat-alternative crops-fallow instead of the typical winter wheat-fallow system. The Resilient Dryland Farming Alliance (RDFA) is a product of a farmer-led initiative. The RDFA is evaluating intensified wheat-based systems to integrate alternative crops in order to reduce the number of fallow periods, to enhance soil health, break cycles of disease, decrease fertilizer requirements, and change or reduce herbicide inputs. This report includes preliminary data for the second year of a three-year study. Data showed that winter pea and brown mustard produced the greatest amount of biomass of the alternative crops tested at both sites. Weed biomass was lowest under winter pea treatments at both sites. Brown mustard and flax both had higher yields at the Umatilla County site compared to the Morrow County site. Despite producing higher biomass and considerable yields, residual moisture under brown mustard was similar to fallow moisture in topsoils and was similar to other alternative crops at deeper depths. Due to a historic drought in crop year 2020-2021, biomass produced by many of the alternative crops was lower than expected.