Experiences with PSNT in North Carolina

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Experiences with PSNT in North Carolina

• David H. Hardy
• Soil Testing Section
• Agronomic Division- NCDACS

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NC Broiler Production
Piedmont Research Station (PRS)
Union Co.
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Broiler House Litter

• N-29.0 P2O5-26.8 K2O-40.0
• lb. of plant available on wet ton basis
• Broadcast application
• gt 11,000 samples (1999-2006)
• Use rates are 4 6 tons per acre, not always
  yearly
• Excellent source of nutrients
• Environmental concerns- N and P

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General Thoughts on Testing Soils for N

• N is very dynamic in our SE soils
• Not very predictable
• Coastal plains soils
• Piedmont soils??
• Time needed for sampling
• Busy time of the year with other crops
• Quality of samples
• Representative of field (12 inch depth)

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2005 PSNT Test

• Strip test- history of poultry litter
• Four 12-row strips with only 20 GPA of 30 UAN
  applied at planting
• Four 12-row strips with 40 GPA of 30 UAN, split
  applied
• V5 PSNT was 35.5 ppm nitrate-N average
• Yield at harvest with weigh wagon
• Cornstalk testing- Blackmer (August 30)

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700 to 2000 ppm is optimal, gt 2000 is excess.
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Brooks Farm- 2006

• Site with history of litter application
• Strip test- 4 strip combinations
• 30 N at V6 _at_ 15 GPA vs. no N (NN)
• 6 soil samples _at_ V5
• Tissue samples _at_ tassel
• Yield monitor plus hand-harvest
• Cornstalk testing- Blackmer (August 30)

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Soil Test Results- Brooks 2006

• W/V 0.96 g cc-1
• CEC- 10.2 meq 100 cc-1
• pH 6.0
• P- 251 mg dm-3
• K- 301 mg dm-3
• 32 ppm NO3-N
• Range (22 - 46)

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700 to 2000 ppm is optimal, gt 2000 is excess.
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Piedmont Research Station- 2006

• Treatment Blocks (subsamples)
• Poultry Litter (L)
• Poultry Litter Starter (LS)
• Poultry Litter Starter SD (LSSD)
• 8 soil samples per treatment- PSNT
• Leaf N at V5, T, grain yield

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PRS-2006 Results
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Piedmont Research Station- 2007

• Site with history of litter
• N Rate treatments- 0, 30, 60, 120
• 34-0-0 at V5
• RCBD with 4 reps
• 1 soil sample per rep- PSNT
• Leaf N at T, silage grain yield

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PRS Soil Data- 2007
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a
a
ab
b
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a
ab
b
b
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a
a
a
a
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SUMMARY

• Appears to be significant available N where
  litter is applied on Piedmont soils
• On Piedmont soils, PSNT may be of benefit
• Lab would be well positioned to handle samples in
  May