Moving Beyond NDVI for
Active Sensing in Cotton
Kevin F. Bronson
US Arid Land Agric. Res. Center,
USDA-ARS, Maricopa, AZ
Introduction
• Canal infrastruture, and level land means that level-basin
surface irrigation in raised beds in the predominant irrigation
system in Arizona for cotton production. However, overhead
spinklers are coming into central Arizona.
• Nitrogen fertilizer is usually managed with early season
ground applications followed by “fertigations” i.e. dribbling
32-0-0 UAN into the canal.
• Proximal sensing can guide in-season N applications, and
improve low NUE in cotton.
Objectives
• Compare vegetations indices for ability to detect early to
mid-season N deficiencies in irrigated cotton.
• Correlate various VIs with first open boll biomass, N uptake
and lint yield.
• Compare NDVI-based N management with soil profile NO3
recommendation.
• Test UAN + Agrotain Plus vs. UAN alone
• Test IRTs and ultrasonic height sensors in combo w/ AOS
• Assess N uptake, RE, IE, AE, NO3 leaching and N2O
emissions
Methods
Methods cont.
Methods cont.
Methods
•
•
•
•
•
•
•
•
•
•
Randomized block design, three or four replicates
Six N management treatments in 2012-13, 8 in 2014
Plots 8, 40-in. rows x 550’ in 2012-13, 6 rows x 120’ in 2014
Planted DP 1044 B2RF on May 1, 2013 and 2014
Irrigated 740 to 850 mm for 85 -100% ET replacement
Active optical sensor used weekly from pinhead square to
first open boll, one 1 m above canopy
Apogee IRR-P IRTs at 0.8 m, nadir and 30o
Honeywell 943 or MaxBotix HRXL-MaxSonar®-WRTM
ultrasonic height sensors
Neutron probe soil moisture measured weekly to 180 cm
Harvest on early November
Nitrogen Treatments for cotton, Maricopa, AZ, 2012 and 2013
Nitrogen treatment
Fertilization
mode
Fertilizer
source
1. Zero-N
2. Soil test-based N†
3. Soil test-based N†
4. Soil test-based N†
5. Reflectance-based
N‡
6. Reflectance-based
N§
Fertilizer
rate
(lb N/ac)
0
Notes
2 splits:
132
1st square,
(106 in 2013) 1st bloom†
Knife
Urea amm.
nitrate
Fertigate
Urea amm.
nitrate
132
or 106
2 fertigations
:
1st square,
1st bloom†
Fertigate
Amm sulfate or
132
UAN+Agrotain or 106
2 fertigations
:
1st square,
1st bloom†
Knife
Urea amm.
nitrate
Fertigate
Urea amm.
nitrate
2 splits:
66
1st square,
st
(53 in 2013) 1 bloom†
66
or 53
2 irrigations:
1st square,
1st bloom†
† Based on lint yield goal of 1500 lb/ac, 175 lb N/ac requirement, minus 0- 36 in soil NO 3-N 20 and 50 lb NO3-N/ac, 2012&13)
irrigation input of 20 lb N/ac (estimated 100 cm irrigation
.
of 2 ppm NO3-N water)
‡ First split equals50 % treatment no. 2, second split based on NDVI relative to treatment no. 2.
N Requirements (lb N/ac) vs. cotton lint yield (bale/ac)
200
180
160
y = 40.2x
2
R = 0.73
N uptake (lb/ac)
140
120
100
80
Stripper
Picker
60
40
20
0
0
0.5
1
1.5
2
2.5
3
Lint yield (ba/ac)
3.5
4
4.5
5
Nitrogen Treatments for sprinkler-irrigated cotton,
Maricopa, AZ, 2014 & 2015
Nitrogen treatment
Fertilizer source
Notes
1. Zero-N
In three splits, first square and first
bloom and mid bloom†
In three splits, first square and first
3. 1.3*Soil test-based N†
bloom and mid bloom†
In three splits, first square and first
4. Soil test-based N†
bloom and mid bloom†
5. Reflectance-based NIn three splits, first square and first
1‡
nitrate
bloom and mid bloom‡
6. Reflectance-based N- Urea amm.
In three splits, first square and first
2§
nitrate
bloom and mid bloom§
7. Reflectance-based N- Urea amm.
In three splits, first square and first
1‡
nitrate
bloom and mid bloom‡
8. Reflectance-based N- Urea amm.
In three splits, first square and first
nitrate +
2§
bloom and mid bloom‡
Agrotain
Plus
† Based on lint yield goal of 4.0 bale/ac,
and
a 200 lb N/ac N requirement, minus 0 - 36 in. soil
NO3-N and estimated irrigation input of 20 lb N/ac (estimated 40 inch irrigation of 2 ppm NO3-N
water).
2. Soil test-based N†
Urea amm.
nitrate
Urea amm.
nitrate
Urea amm.
nitrate +
Agrotain
Plus
Urea amm.
Vegetation indices
NDVI-Red (NDVIR) (Tucker, 1979) was calculated as:
(R800 - R670)/ (R800 + R670)
NDVI-Amber (NDVIA) (Solari et al. 2008) was calculated as:
(R800 - R590)/ (R800 + R590)
Normalized difference red edge index (NDRE) (Gitelson and
Merzlyam 1994) was calculated by as:
(R800 - R730)/ (R800 + R730)
Vegetation indices cont.
Canopy chlorophyll content index (CCCI) (red) (Long, et al.,
2009; Barnes, 2000, Cammarano et al., 2011) was calculated
as:
(NDRE)/ (Red NDVI)
Amber CCCI was calculated as:
(NDRE)/ (Amber NDVI)
The DATT VI (Datt, 1999) was calculated as:
(R800 - R730)/ (R800 - R670)
Vegetation indices cont.
Chlorophyll index (CI590) (Solari et al., 2008) was calculated as:
(R800 - R590) - 1
Photochemical reflective index (PRI) (Garbulsky et al., 2011)
was calculated as:
R590 - R530
Amber NDVI as affected by N management, 2012
Red NDVI as affected by N management, 2012
CI as affected by N management, 2012
Amber NDVI as affected by N management, 2013
Red NDVI as affected by N management, 2013
NDRE as affected by N management, 2013
CI as affected by N management, 2013
Honeywell 943 ultrasonic height sensor as affected by N, 2013
Amber NDVI as affected by N management, 2014
Red NDVI as affected by N management, 2014
NDRE as affected by N management, 2014
DATT as affected by N management, 2014
CCCI as affected by N management, 2014
Petiole-NO3-N as affected by N management,
DP1044B2RF, Maricopa, AZ, 2014
Petiole-NO3-N as affected by N management,
DP1044B2RF, Maricopa, AZ, 2015
Leaf N as affected by N management,
DP1044B2RF, Maricopa, AZ, 2014
Leaf N as affected by N management,
DP1044B2RF, Maricopa, AZ, 2015
Amber NDVI as affected by N management, 2015
Red NDVI as affected by N management, 2015
Green NDVI as affected by N management, 2015
NDRE as affected by N management, 2015
Correlations between VIs and soil/plant parameters,
overhead sprinkler cotton, 2014-2015, Maricopa, AZ
2015
NDVI – Amber
NDVI – Red
NDRE
CCCI
DATT
EM38
Ultrasonic ht
0.49
0.49
0.29
-0.47
-0.45
0.93
0.92
0.76
-0.82
-0.84
Leaf N
N rate
0.48
2014
NDVI – Amber
NDVI – Red
NDRE
CCCI
DATT
0.50
0.50
0.29
-0.51
-0.35
0.30
0.29
0.16
-.025
0.25
0.58
0.59
0.33
0.43
Fixed Nitrogen effects for various VIs by date
from true leave stage to first open boll,
surface irrigation, Maricopa, AZ 2012
Day of
year
139
150
156
165
171
174
177
184
191
200
209
216
NDVIR
NDVIA
NDVIG
*
*
*
NDRE
CCCI
CCCIA
CI
*
*
DATT
PRI
Fixed Nitrogen effects for various VIs by date
from true leave stage to first open boll,
surface irrigation, Maricopa, AZ 2013
Day of
year
143
156
165
170
177
190
200
206
217
231
NDVIR
NDVIA
NDVIG
*
**
*
**
**
*
*
**
**
*
**
NDRE
*
**
**
CCCI
**
CCCIA
CI
*
*
**
**
DATT
**
PRI
Honey
*
*
**
*
*
**
**
Fixed Nitrogen effects for various VIs by date
from true leave stage to first open boll,
sprinkler irrigation, Maricopa, AZ 2014
Day of
year
147
153
161
167
175
181
188
196
203
210
217
NDVIR
NDVIA
NDVIG
*
*
**
NDRE
*
**
**
**
CCCI
*
**
CCCIA
*
*
CI
DATT
PRI
*
*
**
**
*
*
Correlation among peak bloom VIs, first open
boll biomass, total N uptake and lint yield,
Maricopa, AZ 2012-2014
NDVIR
NDVIA
NDVIG
Biomass
TNU
Lint yield
0.32
0.26
0.71
0.29
0.31
0.67
0.45
0.44
0.58
Biomass
TNU
Lint yield
0.59
0.72
0.86
0.49
0.75
0.78
0.49
0.71
0.80
Biomass
TNU
Lint yield
0.52
0.41
0.76
0.51
0.44
0.76
0.41
0.44
0.67
NDRE
CCCI
2012
0.53
0.39
0.63
0.45
0.45
0.30
2013
0.39
0.66
0.40
0.72
0.38
2014
0.21
-0.50
0.39
0.52
-0.80
CI
DATT
PRI
0.27
0.31
0.68
0.48
0.58
0.31
0.36
0.30
0.27
0.46
0.74
0.79
0.50
0.52
0.52
0.44
0.80
-0.40
-0.29
-0.44
-0.38
-0.73
First open boll biomass, N uptake and recovery efficiency, as
affected by N management in surface-irrigated cotton,
Maricopa, AZ 2012
Nitrogen treatment
Fertilization
mode
Fertilizer
source
Zero-N
Fertilizer
rate
Biomass
N uptake
Recovery
efficiency
lb N/ac
lb/ac
lb N/ac
%
0
6558 b
116 b
Seasonal
N2O flux
g N2ON/ac/96 d
64 b
Soil test-based N†
Knife
Urea amm.
nitrate
132
7026 ab
149 a
25 a
139 ab
Soil test-based N†
Fertigate
Urea amm.
nitrate
132
7474 a
147 a
23 a
348 a
Soil test-based N†
Fertigate
Amm.
Sulfate
132
7981 a
155 a
30 a
342 a
Reflectance-based N‡
Knife
Urea amm.
nitrate
66
6103 b
118 b
3a
Reflectance-based N§
Fertigate
Urea amm.
nitrate
66
6970 ab
126 b
15 a
Lint yield, agronomic and internal N use efficiency, as affected
by N management in surface-irrigated cotton, Maricopa, AZ
2012
Nitrogen treatment
Fertilization
mode
Fertilizer
source
Zero-N
Fertilizer
rate
Lint yield
Agron N
use
efficiency
lb N/ac
lb/ac
lb lint/lb N
fert.
0
1450 b
Internal N
use
efficiency
lb N/bale
37.5 ab
Soil test-based N†
Knife
Urea amm.
nitrate
132
1718 a
2.0 a
40.5 a
Soil test-based N†
Fertigate
Urea amm.
nitrate
132
1610 a
1.2 a
43.3 a
Soil test-based N†
Fertigate
Amm. Sulfate
132
1594 a
1.1 a
45.5 a
Reflectance-based
N‡
Knife
Urea amm.
nitrate
66
1714 a
4.0 a
32.3 b
Reflectance-based
N§
Fertigate
Urea amm.
nitrate
66
1671 a
3.3 a
35.3 b
First open boll biomass, N uptake and recovery
efficiency, as affected by N management in surfaceirrigated cotton, Maricopa, AZ 2013
Nitrogen treatment
Fertilization
mode
Fertilizer
source
1. Zero-N
2. Soil test-based N†
Knife
3. Soil test-based N†
Fertigate
4. Soil test-based N†
Fertigate
5. Reflectance-based
N‡
Knife
6. Reflectance-based
N§
Fertigate
Urea amm.
nitrate
Urea amm.
nitrate
Urea amm.
nitrate+Agrotai
n
Urea amm.
nitrate
Urea amm.
nitrate
Fertilizer
rate
Biomass
lb N/ac
lb/ac
lb N/ac
0
7311 a
108 b
106
8122 a
156 a
44 a
106
7927 a
142 a
30.5 a
106
8667 a
142 a
32 a
53
8463 a
143 a
64 a
53
8550 a
131 ab
42 a
N
uptake
Recovery
efficiency
%
Lint yield, agronomic and internal N use efficiency, as affected
by N management in surface-irrigated cotton, Maricopa, AZ
2013
Nitrogen treatment
Fertilization
mode
Fertilizer
source
Zero-N
Fertilizer
rate
Lint yield
Agron.
N use
efficiency
lb N/ac
lb/ac
lb lint/lb N
fert.
0
1467 b
Internal N
use
efficiency
lb N/bale
37.2 b
Soil test-based N†
Knife
Urea amm.
Nitrate
106
1657 a
1.9 a
45.9 a
Soil test-based N†
Fertigate
Urea amm.
Nitrate
106
1543 a
0.9 a
46.0 a
Soil test-based N†
Fertigate
UAN+Agrotain
Plus
106
1742 a
2.7 a
41.3 ab
Reflectance-based
N‡
Knife
Urea amm.
Nitrate
53
1704 a
4.8 a
42.3 ab
Reflectance-based
N§
Fertigate
Urea amm.
Nitrate
53
1772 a
6.1 a
37.1 b
Lint yield, agronomic, and internal N use efficiency, as affected
by N management in sprinkler-irrigated cotton, Maricopa, 2014
Nitrogen treatment
Fertilizer
source
1. Zero-N
Fertilizer
rate
Lint
yield
Agron.
N use
efficiency
Internal N
use
efficiency
lb N/ac
lb/ac
lb lint/lb N
fert.
lb N/bale
0
1462 b
-
40.7 b
2. Soil test-based N†
UAN
160
1605 a
0.9 a
54.0 a
3. 1.3*Soil test-based
N†
UAN
208
1715 a
1.2 a
50.1 a
4. Soil test-based N†
UAN +
Agrotain
Plus
160
1745 a
1.8 a
46.4 a
UAN
80
1704 a
3.0 a
48.5 a
UAN
104
1658 a
1.9 a
49.4 a
7. Reflectance-based
N-1‡
UAN +
Agrotain
80
1672 a
2.6 a
48.4 a
8. Reflectance-based
N-2§
UAN +
Agrotain
Plus
104
1620 a
1.5 a
48.0 a
5. Reflectance-based
N-1‡
6. Reflectance-based
N-2§
First open boll biomass, N uptake and recovery efficiency, as
affected by N management in sprinkler-irrigated cotton,
Maricopa, AZ 2014
Season
Nitrogen treatment
Fertilizer
source
1. Zero-N
Fertilizer
rate
Biomass
N
uptake
Recovery
efficiency
al N 2O
flux
lb N/ac
lb/ac
lb N/ac
%
g N2ON/ac/91d
0
7494 a
130 b
-
30 b
2. Soil test-based N†
UAN
160
8310 a
184 a
34 ab
449 a
3. 1.3*Soil test -based N†
UAN
208
8015 a
180 a
24 b
496 a
UAN +
Agrotain
Plus
160
7887 a
169 a
24 b
107 b
5. Reflectance -based N1‡
UAN
80
8497 a
174 a
55 a
405 ab
6. Reflectance -based N2§
UAN
104
8076 a
172 a
40 ab
282 ab
80
8553 a
170 a
50 ab
259 ab
104
7757 a
163 a
32 ab
213 b
4. Soil test-based N†
7. Reflectance -based N1‡
8. Reflectance -based N2§
UAN +
Agrotain
Plus
UAN +
Agrotain
Plus
Cotton canopy temperature as affected by N management,
surface irrigation, Maricopa, AZ 2014
Summary
• N fertilizer response in lint yield and TNU
all three years was observed, but not
different among N treats.
• NDVI amber, red, and green showed N
deficiency late in 2012 and in 2014.
• NDRE showed N deficiency much earlier
than NDVI.
• CCCI and CI have potential, but were not
consistent.
Summary cont.
• All NDVIS and CI showed high correlation
with lint yield all three years.
• NDVI-based N mgt saves N without
hurting lint yields.
• The Honeywell height sensor
correlation with NDVI was
very high.
Suggestions for NUE Group
• Move to farmers’ fields
• Try NDRE
• Add IRTS (low NDVI < NDVIref with hot leafs =
sandy/dry not needs N)
•
•
•
•
Add height sensors
Measure plant N uptake
Measure soil water
If irrigation is in your area, do N x water,
and also fertigation
• Measure NO3 leaching
• Get involved with HTP
Acknowledgements
Cotton Inc, IPNI, and Koch Agronomic Services