Transcript Development of a SBNRC Calculator for Cotton D. Brian Arnall

Development of a SBNRC
Calculator for Cotton
D. Brian Arnall
Oklahoma State University
W. Raun, J. Solie, M. Stone, R. Taylor,
O. Walsh, D. Edmonds, C. Daft, B. England,
Y. Kanke, B. Desta
Fertilizer N Needs in Cotton
Under Estimation of N Fertilizer and Application of an Insufficient Rate
Loss of Yield, proportional to shortfall
Consumption of Soil N reserve, depletion of soil fertility
Over Estimation of N Fertilizer Needs and Application of a above-optimal
Rate
Excess Vegetative Growth, Increased Plant Growth Regulation Required
Increased Susceptibility to Aphids
Increased Susceptibility to Boll Rot
Delayed Crop Maturity
Increased Difficulty to Defoliate
Potential for Long-Term Decrease in Soil Organic Matter
Increased Need for Liming, through Soil Acidification
Cotton Corp
Estimating Cotton's Nitrogen Needs
R.L. Nichols, Cotton Incorporated and C.J. Green, Texas Tech University
Sensor Based Nitrogen Rate
Calculator
What is needed.
Yield Prediction Model
Response Index
Nitrogen Removal
Nitrogen Use Efficiency.
N Rate = (YP0 * RI – YP0) * %N /
Efficiency
Cotton YP Trial
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
Cotton N study
Treatment
Pre plant N
Side Dress N
Side Dress Timing
1
0
0
2
40
0
3
80
0
4
120
0
5
40
TBD
Early (40-50 DAP)
6
40
TBD
Mid (60-70 DAP)
7
40
TBD
Late (80-90 DAP)
8
40
sensor based
Mid (60-70 DAP)
The Experimental Sites
2006
– 1 Site: Lake Carl Blackwell (LCB)
2-4.D
Late Season Stress
2007
– 3 sites: LCB YP, Altus 439, and Altus N
study
NDVI collected over and between rows
2008
– 4 sites: LCB Irrigated YP, LCB Dryland N
study, Altus 439, and Altus N study
Data Collection
Response in 2007
Yield Potential Model
Why use YP.
– Nitrogen is a model nutrient and according to
Bray need is yield dependent.
Using NDVI as a function of GDD.
Days from Planting or Cumulative GDD
Yield Potential Model
8.0
7.0
43 Locations, 1998-2006
YP0 = 0.409e258.2 INSEY
6.0
R2=0.50
Grain yield, Mg/ha
YP0 + 1Std Dev = 0.590 e258.2 INSEY
5.0
Winter
Wheat
4.0
3.0
2.0
1.0
0.0
0
0.001
0.002
0.003
0.004
0.005
0.006
INSEY
Units: biomass, kg/ha/day, where GDD>0
0.007
0.008
0.009
0.01
PKNP 1998
PKSN 1998
TPSN 1998
PKNP 1999
222 1999
301 1999
EFAA 1999
801 1999
502 1999
PKNP 2000
222 2000
301 2000
EFAA 2000
801 2000
502 2000
HNAA 2000
PKNP 2001
222 2001
301 2001
EFAA 2001
801 2001
PKNP 2002
222 2002
301 2002
EFAA 2002
801 2002
HNAA 2002
502 2003
222 2003
EFAA 2003
PKNP 2004
222 2004
301 2004
502 2004
2005
2006
INSEY DFP
1600
y = 20.331e303.34x
r2 = 0.46
Lint Yield (kg ha -1)
1200
YP0 = 27.04e303.34x
800
LCB06-64DFP
LCB06-66DFP
LCB06-79DFP
LCB07-70DFP
LCB07-77DFP
SWR-60DFP
400
0
0.008
0.009
0.010
0.011
0.012
0.013
0.014
DFP INSEY (NDVI / days from planting to sensing)
Relationship between in season estimate of yield (INSEY) computed from NDVI
readings of cotton collected between 60-80 days after planting, divided by the
number of days of planting to sensing, and measured lint yield from all site years.
Where YP0 = yield potential; YP0 calculated = the mean + one standard deviation.
INSEY Cum GDD
1600
y = 177.41e2216.2x
1200
-1
Lint Yield (kg ha )
r2 = 0.69
YPO = 235.96e2216.2x
LCB06-886CummGDD
800
LCB06-949CummGDD
LCB06-1161CummGDD
LCB06-1215CummGDD
LCB07-1015CummGDD
400
LCB07-1152CummGDD
LCB07-1262CummGDD
SWR-846CummGDD
SWR-999CummGDD
0
0.000
0.000
0.001
0.001
0.001
CumINSEY (NDVI / Cumm GDD)
Relationship between in season estimate of yield (Cum INSEY) computed from
NDVI readings of cotton at growth stages from square to peak bloom (800-1300
Cumm GDD), divided by the number of days of planting to sensing, and measured
lint yield from all site years. Where YP0 = yield potential; YP0 calculated = the
mean + one standard deviation
NDVI Over Time
2
y = -0.0003x + 0.044x - 0.8865
1.0
2
r = 0.70
NDVI
0.8
0.6
0.4
0.2
0.0
30
40
50
60
70
80
90
Days from Planting to Sensing
The trend of NDVI values as days from planting to sensing increases.
100
4.5
Year
1995
1997
1999
2001
2003
1997
1999
2001
2003
1987
1985
1983
1981
1979
1977
1975
1995
1
1993
1.5
1993
2
1991
2.5
1991
1.0
1.0
4.1
4.1
1.7
1.7
1989
Year
1989
1987
3
min:
min:
max:
max:
avg:
avg:
1985
Response Index
1983
4
1981
1979
1977
1975
3.5
1973
1971
Grain yield, Mg/ha
4
1973
1971
Response Index
Response Index
6
5
0 kg N/ha
112 kg N/ha
3
2
1
0
Response Index
Dr. Johnson
Response to added fertilizer nitrogen
RINDVI
– NDVI of the N-Rich Strip / Farmer Practice
RIHarvest
– Yield of the N-Rich Strip / Farmer Practice
RI Harvest and RI NDVI
2.0
y = 1.8579x - 0.932
r2 = 0.39
RI Harvest
1.5
LCB06-64DFP
LCB06-66DFP
LCB06-79DFP
LCB07-70DFP
LCB07-77DFP
SWR-60DFP
1.0
0.5
0.0
0.5
0.8
1.0
1.3
1.5
RI NDVI
Relationship between the response index measured in season, (NDVI of fertilized
plot / NDVI of check plot) from readings of cotton at growth stages from 60 to 80
days after planting, and measured lint yield and the response index measured at
harvest (yield of fertilized plot / yield of check plot) from all site years.
Nitrogen Use and Uptake
Research from different parts of the Cotton
Belt suggests that high-yielding cotton
crops contain about 50-55 lbs. N/bale
–
(Basset et al., 1970; Mullins & Burmester, 1990; Unruh and Silvertooth, 1996). Cotton Corp
OSU Recommends 27 kg / bale (60 lbs N)
Equivalent to .125 kg N / kg Lint, 12.5%
N Components
If all plant components are accounted for in the
algorithm, this results in 146.39 g N kg-1 lint
(70.267 lbs N bale-1).
Higher than the values recorded as optimum N
rates for cotton grown in Oklahoma of 83.0 g N
kg-1 lint. The
Girma et al. (2007a) data closely fit the value of
90 g N kg-1 lint which was calculated from
removal of lint and seed.
Not known if using the N content of only the lint
and seed is adequate
Or if it will be necessary burs, leaves or stems.
Nitrogen Use and Uptake
Maximum N uptake occurred between 49 and 71
days after planting and was 2.9 and 4.3 kg ha-1
day-1 for cotton receiving 84 and 168 kg N ha-1,
respectively.
–
Boquet, D.J., and G.A. Breitenbeck. 2000. Nitrogen rate effect on partitioning of nitrogen
and dry matter by cotton. Crop. Sci., Vol 40 pg 1685-1693
Very little literature.
NUE of 50%.
SBNRC Algorithm
N Rate = (YP0 * RI – YP0) * %N / NUE
potential cotton lint yield, kg/ha = 235.96 e
2216.2 * INSEY
cotton lint yield, kg/ha = 177.41 e 2216.2 *
INSEY
Where:
YP0 = 235.96 e 2216.2 * INSEY
RI = 1.8579 * RINDVI – 0.932
%N = 0.09
NUE = 0.50
The Unknown
Can Cotton “Catch-up” once it is behind?
What should the level of preplant N be?
What is the application window?
Plant Growth Regulators.
Thank you for your attention.
Any Questions??????
The Answer to the Unknown
Time…………..
– Time to see interactions over many
environments.
– Time to increase the robustness of the YP
model.
– Time to have set backs and learn from
mistakes.
N Rate = (YP0 * RI – YP0) * %N / NUE
potential cotton lint yield, kg/ha = 235.96 e
2216.2 * INSEY
cotton lint yield, kg/ha = 177.41 e 2216.2 *
INSEY
Where:
YP0 = 235.96 e 2216.2 * INSEY
RI = 1.8579 * RINDVI – 0.932
%N = 0.09
NUE = 0.50
GDD 
T max  T min
 60 ºF
2
Min .39 bale/ac:185 lb/ac:208 kg/ha
Max 1.45 bale.ac:695 lbs/ac:781 kg/ha
Approx 540 kg/ha : 480 lbs =1 bale
Nitrogen (N) demand of a cotton crop starts out very
low early in the season, begins to pick up starting at
pin-head square, reaches a peak demand at peak
bloom, and gradually declines as the crop
approaches maturity. Nitrogen fertilizer must be
available to the cotton plant in a timely fashion to
meet crop demand. Split N applications coinciding
with actual crop demand allow growers to apply
adequate but not excessive amounts of fertilizer. A
recommended window for N fertilizer application
begins at the pinhead square growth stage and ends
just prior to peak bloom.
Tim C. Knowles, Jack Watson, and Vic Wakimoto
Late Season Nitrogen Fertilizer for Cotton. Part of the 1999 Arizona Cotton Report,
The University of Arizona College of Agriculture