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ARS Home » Pacific West Area » Pendleton, Oregon » Columbia Plateau Conservation Research Center » Research » Publications at this Location » Publication #406634
Research Project: Attaining High Quality Soft White Winter Wheat through Optimal Management of Nitrogen, Residue and Soil Microbes

Location: Columbia Plateau Conservation Research Center

Title: Invited presentation at soil health in the US-Symposium SSSA-SAWMAC Division

Author
item Gollany, Hero

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 1/11/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary: Pending

Technical Abstract: Wheat-fallow rotation and synthetic N fertilizer application is the dominant management practice in the semiarid dryland production system of Pacific Northwest, US. This practice reduces soil organic carbon (SOC) and acidifies the soil. Soil management that changes SOC and soil pH impacts water-soluble silica and adversely affects soil health. A long-term wheat-fallow experiment with several crop residue management practices (NB, no burn; SB, spring burn; and FB, fall burn), three N rates (0, 45, and 90 kg N/ha), and organic amendments (NBM, 22.4 t/ha manure; and NBPV, 2.24 t/ha pea vines) was established in 1931. Soil cores were analyzed for coarse organic matter (COM), FOM, pH, bulk density, and water-soluble C and Si. A long-term no-till experiment (NTA) winter wheat-fallow (W-F) rotation was established in 1982. A second W-F no-till (NTB) was established in 1997 and was converted to a winter wheat-winter pea cover crop (W-P) in 2010. Each experiment had 4 replications of 5 N fertilizer rates (0, 45, 90, 135, and 180 kg/ha/yr) as subplots. The SOC storage for the NBM was 25% higher than for the FB0. Nitrogen application significantly (P < 0.01) decreased Siws by 17%, while applied manure or pea vines significantly (P < 0.05) increased Siws by 10%. Silica solubilization and movement in response to reduced pH were greater in the absence of organic amendments. Increased SOC storage prevented siliceous pan formation and improved soil health. Five-year average wheat yields in the NTB increased significantly (P < 0.0001) with pea cover crop by 0.54, 1.01 and 0.40 Mg/ha compared to the NTA in the 0, 45, and 90 kg N/ha fertilizer, respectively. Replacement of the fallow phase in the W-F cropping system by a pea cover crop can be a successful management option to improve soil health and wheat yields in the Pacific Northwest.