cotton research oklahoma state university. exp. 439, altus ok 1972-2006
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Cotton Research Cotton Research Oklahoma State UniversityOklahoma State University
Exp. 439, Altus OK 1972-2006Exp. 439, Altus OK 1972-2006
Exp. 439
0
200
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1970 1975 1980 1985 1990 1995 2000 2005 2010
Year
Yie
ld,
lb/a
c
0
135 kg n/ha
*
Exp. 439, Altus OK 1972-2006Exp. 439, Altus OK 1972-2006
RI by rate
0
0.5
1
1.5
2
2.5
3
1972 1978 1983 1988 1993 1999 2004
RI
45
90
135
180
225
Exp. 439, Altus OK 1972-2006Exp. 439, Altus OK 1972-2006
0
0.5
1
1.5
2
2.5
3
1972 1978 1983 1988 1993 1999 2004
RI
averaged over N-rates
average RI
N Rate Algorithm TrialN Rate Algorithm Trial
• Location: Lake Carl Blackwell• Plot Size: 20 x 10’• Alley width: 5’• Total area: 95 x 150• Planting Date: May 15, 2006• Harvest Date: October 9, 2006• Fertilizer P applied preplant and
incorporated, 30 lb P2O5/ac as 0-46-0• Tillage: 2 disc’s preplant followed by a rolling
coulter
• Location: Lake Carl Blackwell• Plot Size: 20 x 10’• Alley width: 5’• Total area: 95 x 150• Planting Date: May 15, 2006• Harvest Date: October 9, 2006• Fertilizer P applied preplant and
incorporated, 30 lb P2O5/ac as 0-46-0• Tillage: 2 disc’s preplant followed by a rolling
coulter
Treatment StructureTreatment Structure
TRT Preplant N Rate Topdress N Rate Growth Stage PIX
1 0 0 - As needed
2 50 0 - As needed
3 100 0 - As needed
4 150 0 - As needed
5 200 0 - As needed
6 50 50 Early square As needed
7 50 100 Early square As needed
8 50 150 Early square As needed
9 0 100 Early square As needed
10 0 150 Early square As needed
11 0 200 Early square As needed
12 0 SBNRC Early square As needed
13 50 SBNRC Early square As needed
14 50 0 + PIX
15 200 0 No PIX
1
9
5
3
82131171151012143645
15
3
12
914213104576111283
8714151364110911212
144152711915810613
1
9
5
3
82131171151012143645
15
3
12
914213104576111283
8714151364110911212
144152711915810613
I
IV
II
III
Cotton TrialLake Carl Blackwell
Plot Size : 20’ x 10’Alley Width : 5’Total Area : 95’ x 150’
N
W E
S
N Rate Algorithm TrialN Rate Algorithm Trial
• Variety: Monsanto NG3273B2RF • The Cotton Variety was NexGen
3273B2RF. It is a stacked trait variety with Roundup-Ready Flex (allows for multiple applications of Round-up throughout the growing season) and Bollgard 2 (newest Bt product for cotton). NexGen cotton varieties are stripper varieties
• Variety: Monsanto NG3273B2RF • The Cotton Variety was NexGen
3273B2RF. It is a stacked trait variety with Roundup-Ready Flex (allows for multiple applications of Round-up throughout the growing season) and Bollgard 2 (newest Bt product for cotton). NexGen cotton varieties are stripper varieties
LCB Cotton 5-2-06NH4-N NO3-N K P pHppm ppm ppm ppm5.725 7.075 146 26 6.69
Square growth mid-pointJuly 6, 2006
y = 384.13x - 42.44R2 = 0.136
0
50
100
150
200
250
300
350
400
0.20 0.30 0.40 0.50 0.60 0.70 0.80
NDVI
Lin
t yi
eld
, lb
/ac
Candle white bloom July 10, 2006
y = 467.89x - 74.293R2 = 0.1811
0
50
100
150
200
250
300
350
400
0.20 0.30 0.40 0.50 0.60 0.70 0.80
NDVI
Lin
t yi
eld
, lb
/ac
7-19 Flowering 5-7 days July 19, 2006
y = 642.16x - 265.15R2 = 0.3616
0
50
100
150
200
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400
0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90
NDVI
Lin
t yi
eld
, lb
/ac
7-21 Boll (un developed cotyledon) July 21, 2006
y = 622.37x - 229.01R2 = 0.3414
0
50
100
150
200
250
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350
400
0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90
NDVI
Lin
t yi
eld
, lb
/ac
8-3 Well defined black layerAugust 3, 2006
y = 622.37x - 229.01R2 = 0.3414
0
50
100
150
200
250
300
350
400
0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90
NDVI
Lin
t yi
eld
, lb
/ac
If too much N has been applied what are the visible indicators?If too much N has been applied what are the visible indicators?
• Delayed maturity• Compared to zero-N plots • Leaf N will be higher in the over-
fertilized plots
• Delayed maturity• Compared to zero-N plots • Leaf N will be higher in the over-
fertilized plots
If not enough N has been applied, and more is needed mid-season,what should we look for?
If not enough N has been applied, and more is needed mid-season,what should we look for?
• Leaf N < 90-95 % of over-fertilized plots or strips.
• New fruits can shed• Developing bolls will be smaller
• Leaf N < 90-95 % of over-fertilized plots or strips.
• New fruits can shed• Developing bolls will be smaller
What to do?What to do?
• Zero-N Strip
• Farmer Practice
• Nitrogen Rich Strip
• N management in Texas and Oklahoma is too N rich.
• Zero-N Strip
• Farmer Practice
• Nitrogen Rich Strip
• N management in Texas and Oklahoma is too N rich.
ENVIRONMENT ?
• Improved Mid-Season N Management• Can we estimate RI in cotton similar to
wheat and corn?• Can we estimate yield potential and use a
YP0 * RI algorithm approach?
• The Ramp Calibration Strip should help us to define optimum N rates and to avoid excessive vegetative growth
• Improved Mid-Season N Management• Can we estimate RI in cotton similar to
wheat and corn?• Can we estimate yield potential and use a
YP0 * RI algorithm approach?
• The Ramp Calibration Strip should help us to define optimum N rates and to avoid excessive vegetative growth
N ManagementN Management
• Preplant Soil Test 0-24”• Dryland: 30-50 lb N/acre• Irrigated: 60 lb N/bale of yield goal• Mid-season N (June, 1st square)• Use of N Rich and 0-N (visual)• Last N Applied (peak bloom)
• Preplant Soil Test 0-24”• Dryland: 30-50 lb N/acre• Irrigated: 60 lb N/bale of yield goal• Mid-season N (June, 1st square)• Use of N Rich and 0-N (visual)• Last N Applied (peak bloom)
Sensor Based N AlgorithmSensor Based N Algorithm
• On-off based on vegetative Green optimum and coverage threshold
• On-off decision of “if/then, and/or” for N or growth regulator
• To start, these decision tools need to be simple (yes/no). Management zones, (high-med-low) approaches can come later.
• On-off based on vegetative Green optimum and coverage threshold
• On-off decision of “if/then, and/or” for N or growth regulator
• To start, these decision tools need to be simple (yes/no). Management zones, (high-med-low) approaches can come later.