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Corn Yield Response to Starter P Fertilizer and ‘Avail’ P Fertilizer Enhancer Ron Gehl Sheri Cahill Deanna Osmond Dept. of Soil Science NC State University.

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Presentation on theme: "Corn Yield Response to Starter P Fertilizer and ‘Avail’ P Fertilizer Enhancer Ron Gehl Sheri Cahill Deanna Osmond Dept. of Soil Science NC State University."— Presentation transcript:

1 Corn Yield Response to Starter P Fertilizer and ‘Avail’ P Fertilizer Enhancer Ron Gehl Sheri Cahill Deanna Osmond Dept. of Soil Science NC State University SSSNC Annual Meeting 2010

2 Average Soil Test Phosphorus

3 Soil Test Phosphorus: Corn/Soybean Rotation

4 Starter P as a Corn Management Option In some geographic regions, starter P has been shown to increase crop yields even when STP is relatively high Response dependent on field management, early- season weather, field issues P availability a concern in many NC soils – need verification of crop response to starter P in NC cropping systems and soils ‘New’ products currently marketed to possibly enhance P availability from applied fertilizers

5 Initial P Starter Research Trials in NC Work by Osmond et al. in 2005, sites at 17 counties for corn; 14 sites at 8 counties for cotton 39 sites at 17 counties for corn; 14 sites at 8 counties for cotton STP > 100 STP > 100 N-only starter vs. N+P starter (20-30 lbs N and/or P 2 O 5 per ac) N-only starter vs. N+P starter (20-30 lbs N and/or P 2 O 5 per ac)

6 Corn Yields and Soil Test Phosphorus Levels

7 Corn Yields: Coastal Plain

8 Is Starter P Necessary on Very High STP Soils? Data from 2005 & 2006 should have shown differences due to the cool, wet spring Across all locations, no difference

9 Theory behind AVAIL: Promotional Claims Negatively charged organic co-polymer NOT a slow release product or nutritional product NOT a slow release product or nutritional product Maleic and itaconic acids Maleic and itaconic acids Increases negative charge around fertilizer, essentially attempts to increase CEC Reduces formation of insoluble P – Al, Ca, Fe complexes Enough to make a difference?

10 Properties of Maleic and Itaconic Acids Maleic Acid Organic compound Two carboxyl groups Soluble in water Similar to organic acids that are pumped out of roots Itaconic Acid Organic compound Formed from the distillation of citric acid Used in plastics There is no published information on the mode of action for Maleic-Itaconic copolymer in soil or in agricultural applications

11 Phosphorus Fertilizer Trials: Two studies with different design, each evaluating similar response variables. Objectives Determine whether starter P fertilizer is useful on soils with STP of medium, high, or very high (PI>25) Evaluate the use of starter P fertilizer, with and without Avail fertilizer enhancer, on early season plant color and height, plant nutrient uptake, stover/silage yield, and grain yield.

12 Soil Interpretation Indexes IndexInterpretationResponse 0-10Very LowHigh 11-25LowHigh 26-50MediumMedium/Low HighNone/Low 100+Very HighNone PI * 1.2 = ppm M-3 P PI * 2.1 ~ lb P/ac to 8”

13 Experiment One: 2007 & 2008 Medium Soil Test P (25-50 PI), High Soil Test P ( PI), and Very High Soil Test P (> 100) Locations: Waynesville (CT), Salisbury (NT), and Fletcher (CT) Treatments Starter 30 lb N ac -1 Starter 30 lb N ac -1 Starter 30 lb N ac -1 and 30 lb P ac -1 Starter 30 lb N ac -1 and 30 lb P ac -1 Starter 30 lb N ac -1 and 30 lb P ac -1 + Avail Starter 30 lb N ac -1 and 30 lb P ac -1 + Avail N source: ; P source: N source: ; P source: N added to all treatments at V6 for a total of 200 lb N ac -1 N added to all treatments at V6 for a total of 200 lb N ac -1 P applied in 4” band over the row P applied in 4” band over the row RCBD, 4 Replications

14 Experiment One: 2007 & row plots, 25’ or 30’ long Plant height determined ~3 weeks after emergence Relative color also determined, scaled 0 (dark green) to 3 (yellow or purple) Corn grain yield from center 2 rows of each plot (20’ total), corrected to 15.5% moisture Tissue and grain samples at harvest for N and P analysis

15 Corn Yield 2007 & 2008: Fletcher High Soil Test Phosphorus

16 Corn Yield 2007 & 2008: Salisbury High Soil Test Phosphorus

17 Corn Yield 2007 & 2008: Waynesville High Soil Test Phosphorus

18 Corn Yield 2008: Waynesville Medium Soil Test Phosphorus

19 Corn Yield 2007 & 2008: Salisbury Medium Soil Test Phosphorus

20 Corn Yield 2008: Fletcher Low Soil Test Phosphorus

21 Trial 1 Conclusions: Starter Phosphorus Fertilizer Yields similar across STP levels No treatment affect on grain or silage yield No treatment affect on grain N or P For mineral soils, starter phosphorus fertilizer is not necessary for corn when soil test P is high or very high For piedmont and mountain soils, starter phosphorus fertilizer may not be necessary for corn when soil test P is medium No advantage to Avail fertilizer enhancer on any measured variables

22 Experiment Two: 2008 & 2009 P Rate Trial Medium Soil Test P (25-50 PI) Location: Fletcher P recommendation: 70 lb P ac -1 Starter Fertilizers 39 lb N ac -1 N 39 lb N ac -1 N 39 lb N ac -1 N + 25, 50, 75, 100, 125 lb P ac lb N ac -1 N + 25, 50, 75, 100, 125 lb P ac lb N ac -1 N + Avail + 25, 50, 75, 100, 125 lb P ac lb N ac -1 N + Avail + 25, 50, 75, 100, 125 lb P ac -1 Starter surface banded 2” to side of seed furrow Starter surface banded 2” to side of seed furrow N source: 30%UAN; P source: N added to all treatments at V6 for a total of 230 lb N ac -1

23 Experiment Two: 2008 & 2009 P Rate Trial RCBD, 4 or 5 replications 4-row plots, 30’ long Plant height determined ~3 weeks after emergence Relative color also determined, scaled 0 (dark green) to 3 (yellow or purple) Corn grain yield from center 2 rows of each plot (20’ total), corrected to 15.5% moisture Tissue and grain samples at harvest for N and P analysis

24 Plant Color at V6 RatingColor 0Dark green 1Green 2Light green 3Yellow/purple

25 Plant Height at V6

26 Corn Grain Yields: 2008 and 2009

27 Corn Stover: 2008 and 2009

28 Stover P Uptake

29 Trial 2 Conclusions: Starter Phosphorus Rate and Avail No treatment affect on grain yield or stover No treatment affect on grain or stover N or P Early season differences in color and height (2009) did not translate into yield differences For CT mountain soils Starter P fertilizer may not be necessary for corn when soil test P is medium Starter P fertilizer may not be necessary for corn when soil test P is medium No advantage to Avail fertilizer enhancer, regardless of rate, on any measured variables No advantage to Avail fertilizer enhancer, regardless of rate, on any measured variables

30 Take Home Message Starter P not likely to result in positive yield response for corn grown in mineral soils with STP medium or above Avail fertilizer enhancer did not improve yields or P uptake by corn on medium STP soils

31 Acknowledgements Wesley Childres, Soil Science Randy Weisz, Crop Science Ron Heiniger, Crop Science Dan Israel, Soil Science Agrium Corn Growers Association of North Carolina North Carolina Small Grain Growers Association NCDENR – USEPA 319 funds Southern States Yara

32 Participants in Starter P Study Sheri Cahill – NCSU, Soils Amy Johnson – U. Tenn David Hardy – NCDA&CS Gaylon Ambrose – Beaufort/Hyde Anthony Cole – Buncombe, Alleghany, Rowan, Henderson Seth Nagy/Lynn Howard – Caldwell Mark Powell – Camden C. Mike Williams – Chowan Al Wood – Pasquotank Mike Carroll – Craven Josh Gady - Duplin Keith Wood - Cherokee Art Bradley – Edgecombe Louie Johnson – Greene Mark Keene – Lenoir Josh Beam – Lincoln Bryant Spivey – Onslow Ben Knox – Union Kevin Johnson – Wayne Norman Harrell - Wilson Producers who helped!

33 Thank You. Questions?

34 Maleic and Itaconic Acid: Skeletal Frame

35 Phosphorous in an acidic soil environment Soil system has significant Fe and Al oxides CEC occupied by Fe and Al

36 Phosphorous in an acidic soil environment Formation of insoluble Fe and Al Phosphates P no longer readily available to plants

37 Phosphorous in an acidic soil environment Formation of insoluble Fe and Al Phosphates P no longer readily available to plants

38 Concept of P Fertilizer treated with AVAIL AVAIL adds negative charge around the P molecules

39 Concept of P Fertilizer treated with AVAIL Soil cations attracted to the negative charges, allowing P molecules to remain plant available

40 Current specialty crop fertility projects

41 Fundamental Issues Fertilizer cost, limited product availability at local level Consequently, many growers have reduced or eliminated fertilizer inputs….impact on longer term effects??? Consequently, many growers have reduced or eliminated fertilizer inputs….impact on longer term effects??? Growers looking for alternatives - renewed industry push of ‘specialty’ fertilizers and products “Green” movement: public perception and environmental issues at the forefront Buy local! Produce quality vs. quantity

42 Conclusions: Starter Phosphorus Fertilizer For mineral soils, starter phosphorus fertilizer is not necessary for corn when soil test P is high or very high For piedmont and mountain soils, starter phosphorus fertilizer may not be necessary for corn when soil test P is medium Starter phosphorus still needed for organic or mineral organic soils for low, medium and high soil test P

43 Corn Grain Yields: Fletcher

44 Corn Yields Grain: Fletcher

45 Plant Height at V6


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