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Evaluation Nitrogen and Phosphorus Placement With Strip Tillage for Irrigated Pacific Northwest Corn Production David Tarkalson and Dave Bjorneberg Agricultural Research Service, USDA Kimberly Idaho Southern Idaho Nutrient Management Conference March 9, 2010 Shoshone, ID

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Objective Evaluate corn production under strip tillage (ST) and conventional tillage (CT), and various N and P fertilizer placements under conditions found in southern Idaho

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Methods Conducted field studies in 2007 and 2009 Soil = Portneuf silt loam, 1-2% slope History = 80-100 years of furrow irrigation. Erosion/Deposition Previous crop = Alfalfa Current irrigation practices 2007 = Furrow 2009 = Linear move system (18 years) Treatments 1.Strip Tillage Band P Broadcast N 2.Strip Tillage Broadcast P 22 N 3.Strip Tillage Band P Band N 4.Conventional Tillage Broadcast P 22 N 5.Conventional Tillage Broadcast P Broadcast N Conventional Tillage = Chisel Plow, Tandem Disk N rate = 105 lbs N/acre + Alfalfa credit (60 lbs N/acre) 46-0-0 and 32-0-0 P rate = 60 lbs P 2 O 5 /acre 11-52-0 and 10-34-0

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515 Ft

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8 Row Plots

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Top Bottom

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Top Harvest 60 ft of Row

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Soil Depth (in)Analyte 2007 TopBottom 0-12Organic Matter (%)1.8 1.6 Free Lime (CaCO 3 ) (%)20.1 10.4 Bicarbonate P (mg/kg)11.3 26.5 12-24Organic Matter (%)1.0 1.6 Free Lime (CaCO 3 ) (%)20.3 8.8 Bicarbonate P (mg/kg)3.2 9.2 2009 0-12Organic Matter (%)1.8 2.0 Free Lime (CaCO 3 ) (%)20.5 10.0 Bicarbonate P (mg/kg)9.3 10.1 12-24Organic Matter (%)1.0 1.7 Free Lime (CaCO 3 ) (%)19.7 9.0 Bicarbonate P (mg/kg)1.2 1.9 Soil Properties

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Top Corn Grain Yield 20072009 ST-Band P-Broadcast N ST-Broadcast P- 22 N ST-Band P-Band N CT-Broadcast P- 22 N CT-Broadcast P-Broadcast N ST-Band P-Broadcast N ST-Broadcast P- 22 N ST-Band P-Band N CT-Broadcast P- 22 N CT-Broadcast P-Broadcast N

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ab a b b Top Corn Grain Yield 2007 a ab a b b 2009 11 bu 26 bu ST-Band P-Broadcast N ST-Broadcast P- 22 N ST-Band P-Band N CT-Broadcast P- 22 N CT-Broadcast P-Broadcast N ST-Band P-Broadcast N ST-Broadcast P- 22 N ST-Band P-Band N CT-Broadcast P- 22 N CT-Broadcast P-Broadcast N Economic Advantage (Yield + Tillage) $56/acre Economic Advantage (Yield + Tillage) $114/acre

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Bottom Corn Grain Yield a a a a a 2007 a a a a a 2009 ST-Band P-Broadcast N ST-Broadcast P- 22 N ST-Band P-Band N CT-Broadcast P- 22 N CT-Broadcast P-Broadcast N ST-Band P-Broadcast N ST-Broadcast P- 22 N ST-Band P-Band N CT-Broadcast P- 22 N CT-Broadcast P-Broadcast N

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Total Biomass

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Questions

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ab a b b Top Corn Grain Yield 2007 a ab a b b 2009 11 bu 26 bu

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ab a b b 2007 Top Corn Grain Yield Top 11 bu

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a ab a b b 2009 Top Corn Grain Yield Top 26 bu

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Bottom Corn Grain Yield a a a a a 2007 a a a a a 2009

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a a a a a 2007 Bottom Corn Grain Yield Bottom

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a a a a a 2009 Bottom Corn Grain Yield Bottom

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