Transcript Nitrogen Management and its Influence on N Losses to

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/
7/6/2015
Purpose
• To evaluate the GreenSeeker and SPAD
meter as diagnostic tools for making inseason N applications to corn.
7/6/2015
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).
7/6/2015
Precipitation
Month
May
June
July
August
Sept.
5-mo. Total
7/6/2015
2004
30-yr normal
----- inches ----5.61
3.96
6.42
4.22
7.08
4.47
5.73
4.58
6.92
3.19
31.76
20.42
Treatments
#
1
2
3
4
5
6
Time and Rate of N Application
Total N Rate Preplant 1/
V8
V12
--------------------- lb N/A --------------------0
0
0
0
40
40
0
0
80
80
0
0
120
120
0
0
160
160
0
0
200
200
0
0
1/ Urea PPI
7/6/2015
Treatments cont.
#
7
8
9
10
11
12
Time and Rate of N Application
Total N Rate Preplant 1/
V8 2/
V12
--------------------- lb N/A --------------------80
40
40
0
120
40
80
0
160
40
120
0
120
80
40
0
160
80
80
0
160
120
40
0
1/ Urea PPI
2/ UAN injected between rows
7/6/2015
Treatments cont.
#
13
14
15
16
17
18
Time and Rate of N Application
Total N Rate Preplant 1/
V8
V12 2/
--------------------- lb N/A --------------------80
40
0
40
120
40
0
80
160
40
0
120
120
80
0
40
160
80
0
80
160
120
0
40
1/ Urea PPI
2/ Urea + Agrotain dribbled near the row
7/6/2015
Corn grain yield and N uptake as affected by rate and
time of N application.
Total
Application Time
N Rate
PP
V8
V12
------------------- lb N/A ------------------0
0
0
0
40
40
0
0
80
80
0
0
120
120
0
0
160
160
0
0
200
200
0
0
80
40
40
0
120
40
80
0
160
40
120
0
80
40
0
40
120
40
0
80
160
40
0
120
Corn Grain
Yield N Uptake
bu/A
lb/A
92
40
146
68
176
92
177
99
190
117
188
117
164
88
190
113
190
114
166
84
185
105
186
109
Relative chlorophyll (SPAD) as affected by rate and time
of N application.
Total
Application Time
N Rate
PP
V8
V12
------------------- lb N/A ------------------0
0
0
0
40
40
0
0
80
80
0
0
120
120
0
0
160
160
0
0
200
200
0
0
80
40
40
0
120
40
80
0
160
40
120
0
80
40
0
40
120
40
0
80
160
40
0
120
Corn Grain
V12
R1
----- % ----78
70
91
87
96
92
97
94
98
97
98
98
94
93
95
96
94
94
87
84
90
91
91
91
Correlation between in-season corn growth
parameters and grain yield and N uptake.
Parameter
Plant height, V8
Plant height, V10
Plant height, V12
Total DM, V8
Total DM, V12
Total N uptake, V8
Total N uptake, V12
1/
Corn Grain
Yield
N Uptake
------ r value 1/ -----0.59
0.42
0.87
0.76
0.90
0.80
0.57
0.40
0.88
0.77
0.82
0.70
0.95
0.93
Statistically significant when r > 0.404 (0.05) and r > 0.515
(0.01), df=22.
7/6/2015
Correlation between in-season diagnostic
parameters and grain yield and N uptake.
Parameter
INSEY (53), V7
INSEY (58), V8
INSEY (67), V10
INSEY (72), V12
SPAD, V8
SPAD, V10
SPAD, V12
SPAD, R1
1/
Corn Grain
Yield
N Uptake
------ r value 1/ -----0.56
0.41
0.72
0.56
0.62
0.64
0.74
0.74
0.85
0.75
0.83
0.77
0.95
0.89
0.96
0.93
Statistically significant when r > 0.404 (0.05) and r > 0.515
(0.01), df=22.
7/6/2015
220
Corn grain yield, bu/acre
200
180
160
140
120
100
80
R2 = 0.40
60
0.006
7/6/2015
0.007
0.008
INSEY (V7)
0.009
0.010
220
Corn grain yield, bu/acre
200
180
160
140
120
100
80
60
40
0.0065
7/6/2015
R2 = 0.64
0.0070
0.0075
0.0080
INSEY (V8)
0.0085
0.0090
0.0095
220
Corn grain yield, bu/acre
200
180
160
140
120
100
80
R2 = 0.40
60
0.0085
7/6/2015
0.0090
INSEY (V10)
0.0095
0.0100
220
Corn grain yield, bu/acre
200
180
160
140
120
100
80
R2 = 0.58
60
0.007
7/6/2015
0.008
INSEY (V12)
0.009
0.010
0.0095
0.0090
INSEY (V8)
0.0085
0.0080
0.0075
0.0070
0.0065
0
7/6/2015
50
100
Preplant N Rate (lb/acre)
150
200
0.0095
0.0090
INSEY (V8)
0.0085
0.0080
0.0075
0.0070
0.0065
0.0060
0
7/6/2015
40
80
120
Preplant N Rate, lb/acre
160
200
0.010
INSEY (V12)
0.009
0.008
0.007
0.006
0
7/6/2015
40
80
120
Preplant N Rate, lb/acre
160
200
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 PP+V12
split application compared to the single PP or
split (PP+V8) applications.
• Grain yield was correlated better with relative
chlorophyll at all growth stages (V8, V10,
V12) than with INSEY.
7/6/2015
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.
7/6/2015
THANKS
Gyles Randall
Soil Scientist and Professor
Southern Research and Outreach Center
7/6/2015
[email protected]
http://sroc.coafes.umn.edu/