2008 Joint Annual Meeting (5-9 Oct. 2008): Phosphorus Fertilization of Late-Seeded Winter Wheat in a Chemical Fallow System.
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751-3 Phosphorus Fertilization of Late-Seeded Winter Wheat in a Chemical Fallow System.



Wednesday, 8 October 2008
George R. Brown Convention Center, Exhibit Hall E
Lawrence Lutcher, PO Box 397, Oregon State University, 54173 Highway 74, Morrow County Extension Office/Crop/Soil, Heppner, OR 97836-0678, William F. Schillinger, Dep. of Crop and Soil Sciences, Washington State University, Dryland Research Station, Lind, WA 99341, Neil Christensen, Oregon State University, 4048 NW Live Oak Place, Corvallis, OR 97330-3391, Stewart Wuest, USDA-ARS-NPA-SPNRU, USDA-ARS, PO Box 370, Pendleton, OR 97801 and Donald Wysocki, Oregon State University, Columbia Basin Agric.Res.Ctr., PO Box 370, Pendleton, OR 97801
Winter wheat (Triticum aestivum L.) is produced in the low precipitation (200 to 300 mm) zone of north-central Oregon and east-central Washington using a conventional, tillage-based, summer fallow system.  The no-till, chemical fallow (CF) system is an alternative to the traditional method of farming.  Optimism about CF is tempered by an understanding that yield reductions often are a consequence of delayed (late) seeding.  Late seeding of winter wheat in CF is necessary because seed-zone moisture during optimum (early) planting dates is frequently less than that required for uniform germination and emergence.  Yield reductions from late seeding may be offset, to some extent, by P fertilization.  Effects of fertilization were evaluated for three years in field experiments conducted at nine locations.  Phosphorus applied at rates of 5 and 15 kg P ha-1 increased grain yield by an average of 119 and 211 kg ha-1, respectively.  Yield responses among sites ranged from 0 to 336 kg ha-1 and were most pronounced on slightly acidic soils where initial soil test P levels were less than or equal to 12 mg kg-1.  Yield increases were correlated to improvements in early-season dry matter accumulation, early-season P uptake, and the number of spikes per unit area (SPU).
See more of: Phosphorus, Potassium, and Soil Acidity (Posters)
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