LOW PHYTATE CORN Agronomic Research

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LOW PHYTATE CORNAgronomic Research

• Dept. Soil, Water, Climate
• University of Minnesota

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Environmental Emphasis on Phosphorus, not
Nitrogen

• Phosphorus (P)
• immobile in soil
• erodes w/soil
• surface water
• water habitat
• Issue for general public

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Factors/Issues in LP Corn InterestSwine/Poultry
Rations

• Most P in grain is unavailable to swine/poultry,
  thus inorganic P is added to rations. Result is
  high(er) amount of P in manure.

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Phytic Acid in Corn Grain Standard Low
Phytate
PO4
PO4 available
20
60
PO4
Phytate
80
Phytate
40
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Finishing Hog Diet-P Sources--Per Ton of Feed--
Std Corn
LP Corn
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AGRONOMIC ISSUESwith LP Corn

• . Corn Production
• Effect of new trait on yield
• . Excreted Manure
• Effect of corn on P availability

Research has been/is being sponsored, in part, by
MPPA, NPPC, MCRPC, and Pioneer.
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Agronomic StudiesCorn Production

• Objectives
• What effect will the LP characteristic have on
  corns yield, grain P and stover P concentration,
  and overall P accumulation, especially under a
  wide range of soil P test values?

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Statistical Significance of Parameters on Corn
Variables
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Effect of LP Characteristic and Hybrid on Grain
Yield4 Site-Years, Southern Minnesota
-5
-3
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Effect of LP Characteristic on Corn Grain P
Content6 Site-Years, 2 Hybrids, Minnesota
-5.0
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Agronomic Studies-CornSummary

• Grain yield and P content are less with the LP
  characteristic.
• Yield should improve as further conversions are
  made in breeding process. Extraneous donor genes
  still present.

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Agronomic StudiesManure from LP Corn

• Objectives
• Will the change in phytate levels in corn grain
  fed to swine affect the soil (plant) availability
  of P when the manure is applied to soil?

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Linear Effect of Added P on Soil Test P Levels
Illustrative example for 3 P Sources over 3 P
tests at 1 Date on 1 Soil.
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Regression Coefficients as a Function of Three P
Sources2 Soils, 8 Dates, 3 Tests
Days after Application
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Agronomic Studies-ManureSummary

• Manure from swine with LP corn diets resulted in
  approximately 20 less soil available P as
  measured by soil P tests

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IMPACT ONMANURE APPLICATION MANAGEMENT
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LP Corn and Manure Rates

• N-Based
• 160/(53 x 0.7)
• 4,300 GPA

• Swine finishing unit
• 53-39-35 lb/1000 gal.
• Knife-inject manure
• 70 N availability
• 80 P availability
• Continuous Corn
• 160 bu/acre
• 160-70-60 lb/acre

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LP Corn and Manure Rates

• P-Based
• 70/(39 x 0.8)
• 2,200 GPA

• Swine finishing unit
• 53-39-35 lb/1000 gal.
• Knife-inject manure
• 70 N availability
• 80 P availability
• Continuous Corn
• 160 bu/acre
• 160-70-60 lb/acre

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LP Corn and Manure Rates

• P-Based
• w/ LP Corn
• 70/(27 x 0.64)
• 4,000 GPA

• Swine finishing unit
• 53-39(27)-35 lb/1000 gal
• Knife-inject manure
• 70 N availability
• 80(64) P availability
• Continuous Corn
• 160 bu/acre
• 160-70-60 lb/acre

(30 reduction in P)
(20 reduction in availability)
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LOW PHYTATE CORNSummary

• The use of LP corn allows for similar
  (practical) manure application rates with an
  N-based or P-based system, with a significant
  reduction in P application amounts.