Experiences with Remote Sensing for Preplant and Split Applications of N for Corn

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Experiences with Remote Sensing for Preplant and
Split Applications of N for Corn

• Gyles Randall and Jeff Vetsch
• University of Minnesota
• Southern Research and Outreach Center
• http//sroc.coafes.umn.edu/

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Purpose

• To evaluate the GreenSeeker and SPAD meter as
  diagnostic tools for making in-season N
  applications to corn.

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Procedures

• Previous crop Corn removed for silage
• Tillage Chisel plow spring field cultivate
• Soil Nicollet-Webster complex
• Hybrid date DKC 51-41 at 33,000
• plants/A planted on May 1.
• N applied 4/30 (PP), 6/28 (V8), 7/13 (V12)
• Sensing dates 6/23 (V7), 6/28 (V8), 7/7
• (V10), 7/12 (V12), and 7/26 (R1).

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Precipitation
Month 2004 30-yr normal
----- inches ----- ----- inches -----
May 5.61 3.96
June 6.42 4.22
July 7.08 4.47
August 5.73 4.58
Sept. 6.92 3.19
5-mo. Total 31.76 20.42
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Treatments
Time and Rate of N Application Time and Rate of N Application Time and Rate of N Application Time and Rate of N Application
Total N Rate Preplant 1/ V8 V12
--------------------- lb N/A --------------------- --------------------- lb N/A --------------------- --------------------- lb N/A --------------------- --------------------- lb N/A ---------------------
1 0 0 0 0
2 40 40 0 0
3 80 80 0 0
4 120 120 0 0
5 160 160 0 0
6 200 200 0 0
1/ Urea PPI
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Treatments cont.
Time and Rate of N Application Time and Rate of N Application Time and Rate of N Application Time and Rate of N Application
Total N Rate Preplant 1/ V8 2/ V12
--------------------- lb N/A --------------------- --------------------- lb N/A --------------------- --------------------- lb N/A --------------------- --------------------- lb N/A ---------------------
7 80 40 40 0
8 120 40 80 0
9 160 40 120 0
10 120 80 40 0
11 160 80 80 0
12 160 120 40 0
1/ Urea PPI 1/ Urea PPI 1/ Urea PPI
2/ UAN injected between rows 2/ UAN injected between rows 2/ UAN injected between rows
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Treatments cont.
Time and Rate of N Application Time and Rate of N Application Time and Rate of N Application Time and Rate of N Application
Total N Rate Preplant 1/ V8 V12 2/
--------------------- lb N/A --------------------- --------------------- lb N/A --------------------- --------------------- lb N/A --------------------- --------------------- lb N/A ---------------------
13 80 40 0 40
14 120 40 0 80
15 160 40 0 120
16 120 80 0 40
17 160 80 0 80
18 160 120 0 40
1/ Urea PPI 1/ Urea PPI 1/ Urea PPI
2/ Urea Agrotain dribbled near the row 2/ Urea Agrotain dribbled near the row 2/ Urea Agrotain dribbled near the row 2/ Urea Agrotain dribbled near the row
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Corn grain yield and N uptake as affected by rate
and time of N application.
Total Application Time Application Time Application Time Corn Grain Corn Grain
N Rate PP V8 V12 Yield N Uptake
------------------- lb N/A ------------------- ------------------- lb N/A ------------------- ------------------- lb N/A ------------------- ------------------- lb N/A ------------------- bu/A lb/A
0 0 0 0 92 40
40 40 0 0 146 68
80 80 0 0 176 92
120 120 0 0 177 99
160 160 0 0 190 117
200 200 0 0 188 117
80 40 40 0 164 88
120 40 80 0 190 113
160 40 120 0 190 114
80 40 0 40 166 84
120 40 0 80 185 105
160 40 0 120 186 109
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Relative chlorophyll (SPAD) as affected by rate
and time of N application.
Total Application Time Application Time Application Time Corn Grain Corn Grain
N Rate PP V8 V12 V12 R1
------------------- lb N/A ------------------- ------------------- lb N/A ------------------- ------------------- lb N/A ------------------- ------------------- lb N/A ------------------- ----- ----- ----- -----
0 0 0 0 78 70
40 40 0 0 91 87
80 80 0 0 96 92
120 120 0 0 97 94
160 160 0 0 98 97
200 200 0 0 98 98
80 40 40 0 94 93
120 40 80 0 95 96
160 40 120 0 94 94
80 40 0 40 87 84
120 40 0 80 90 91
160 40 0 120 91 91
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Correlation between in-season corn growth
parameters and grain yield and N uptake.
Corn Grain Corn Grain
Parameter Parameter Parameter Yield N Uptake
------ r value 1/ ------ ------ r value 1/ ------
Plant height, V8 Plant height, V8 Plant height, V8 0.59 0.42
Plant height, V10 Plant height, V10 Plant height, V10 0.87 0.76
Plant height, V12 Plant height, V12 Plant height, V12 0.90 0.80
Total DM, V8 Total DM, V8 Total DM, V8 0.57 0.40
Total DM, V12 Total DM, V12 Total DM, V12 0.88 0.77
Total N uptake, V8 Total N uptake, V8 Total N uptake, V8 0.82 0.70
Total N uptake, V12 Total N uptake, V12 Total N uptake, V12 0.95 0.93
1/ Statistically significant when r gt 0.404
(0.05) and r gt 0.515 (0.01), df22.
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Correlation between in-season diagnostic
parameters and grain yield and N uptake.
Corn Grain Corn Grain
Parameter Parameter Parameter Yield N Uptake
------ r value 1/ ------ ------ r value 1/ ------
INSEY (53), V7 INSEY (53), V7 INSEY (53), V7 0.56 0.41
INSEY (58), V8 INSEY (58), V8 INSEY (58), V8 0.72 0.56
INSEY (67), V10 INSEY (67), V10 INSEY (67), V10 0.62 0.64
INSEY (72), V12 INSEY (72), V12 INSEY (72), V12 0.74 0.74
SPAD, V8 SPAD, V8 SPAD, V8 0.85 0.75
SPAD, V10 SPAD, V10 SPAD, V10 0.83 0.77
SPAD, V12 SPAD, V12 SPAD, V12 0.95 0.89
SPAD, R1 SPAD, R1 SPAD, R1 0.96 0.93
1/ Statistically significant when r gt 0.404
(0.05) and r gt 0.515 (0.01), df22.
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Conclusions

• Although statistical differences were not found
  among the PP, V8, and V12 N application times,
  grain yield was 10 to 12 bu/A greater when the
  80-lb N rate was applied PP compared to split
  between 40 lb/A PP and 40 lb/A either at V8 or
  V12 in this wet year.
• Relative leaf chlorophyll at the R1 growth stage
  was considerably less for the PPV12 split
  application compared to the single PP or split
  (PPV8) applications.
• Grain yield was correlated better with relative
  chlorophyll at all growth stages (V8, V10, V12)
  than with INSEY.

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Conclusions cont.

• INSEY was minimally affected by PP N rates
  between 40 and 200 lb/A, suggesting that this
  diagnostic criteria may have limited value if
  some N has been applied preplant for corn after
  corn.
• If no N was preplant applied and the initial
  application was made at V8, corn yields would
  likely be reduced significantly.

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THANKS

• Gyles Randall
• Soil Scientist and Professor
• Southern Research and Outreach Center
• grandall_at_umn.edu
• http//sroc.coafes.umn.edu/