Nitrogen Timing for Sidedress Applications in the Eastern Corn Belt and Algorithm Study Update

1
Nitrogen Timing for Sidedress Applications in the
Eastern Corn Belt and Algorithm Study Update

• Robert W. Mullen
• Algorithm Workshop
• August 11, 2005

2
Issue

• Increased use of liquid attachments on planters
• Decreased use of 2x2 application equipment
• Lower rates of starter N
• Typical sidedress near V3 (as soon as rows can be
  distinguished)
• Can we delay sidedress applications in this
  system?

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Sidedress Application Timing

• Study from last year on timing of sidedress
  application without starter
• N sources UAN (coulter injected), ammonium
  nitrate (preplant only)
• Timings PP, V4, V8
• Three rates 0, 60, 120, 180 lb N/acre
• Reps 4
• RCBD
• Plot size 4 rows (30 inch spacing) by 30 ft

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Sidedress Study

• Yield data

Timing Rate Yield (bu/acre)
--- 0 91
PP 60 111
PP 120 136
PP 180 158
V4 60 145
V4 120 161
V4 180 167
V8 60 133
V8 120 141
V8 180 149
Contrasts PgtF
Rate 0.0001
Timing 0.0047
Timing PP 135 V4 158 V8 141
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Sidedress Timing

• Obviously dependent upon the weather (some years
  we can wait I suspect)
• Continued this past year
• Will include starter treatments next year
• Same question as last year When can we
  identify response to N reliably?

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Algorithm Study

• Two locations West Central Ohio, Northeastern
  Ohio
• Tillage Conservational (chisel plow in the fall)
• Timing V6-V8 (a little early, but crop was
  noticeably stressed)
• Syringe application of fertilizer (not a good
  idea-too much work!)

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Algorithm Study

• Site 1 West Central Ohio
• Planted May 10
• Sidedressed June 29
• Population 30,000 seeds/acre

Treatment Rate, lb N/acre
OSU, 0-S 44 (24-64)
OSU, 40-S 35 (3-70)
NU, 0-S 162 (153-181)
NU, 40-S 132 (110-143)
MU, 0-S 180 (126-265)
MU, 40-S 142 (104-217)
VT, 0-S 66 (59-76)
VT, 40-S 73 (60-95)
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Algorithm Study

• Site 2 Northeastern Ohio
• Planted May 9
• Sidedressed July 5
• Population 30,000 seeds/acre

Treatment Rate, lb N/acre
OSU, 0-S 9 (0-17)
OSU, 40-S 10 (4-14)
NU, 0-S 160 (133-183)
NU, 40-S 178 (173-182)
MU, 0-S 165 (101-326)
MU, 40-S 125 (73-125)
VT, 0-S 59 (44-67)
VT, 40-S 63 (45-77)
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Additional Studies

• Populating a response index for corn in Ohio
• Identifying N response early during the growing
  season
• Six additional N rates studies

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Thanks!!

• Thanks to Fluid Fertilizer Foundation for funding
  research project!
• Remember we will be presenting findings at Fluid
  Fertilizer Annual Meeting in Scottsdale, AZ this
  February!

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Temporal Variability
Year Rel check ( of 180 lb rate) Opt N rate (rel), lb/ac
1998 67 177
1999 85 174
2000a 91 240
2000b 91 166
2001 81 211
2002 85 158
2003 58 236
2004 96 150
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Questions Discussion