Watering Cotton
when to “hold’em” and
when to “fold’em”
Kater Hake and Glen Ritchie
Why bother
irrigation?
Bother learning
– yield willabout
take care
of it
1100
1000
900
800
700
600
500
400
300
200
Plant breeders will take care of it
US Average
Average of States (without Texas)
Texas
Why bother learning about irrigation?
Plant breeders will take care of it
Nature Outlook 2015 528:S1-S17 Genome Editing
Bother learning about irrigation?
We need all the fiber you can grow
70%
Cotton’s Share (fibers & filaments)
of Asian Mill-Use by Region
60%
South Asia
61%
61%
Southeast Asia
28%
23%
China
34%
50%
40%
30%
20%
10%
13%
Northeast Asia
15%
15%
0%
Fiber Organon
https://scripps.ucsd.edu/programs/keelingcurve/
Bother learning about irrigation?
Because it’s important to growers
• Electronic survey from
April 1 to June 30, 2015
• Survey objectives
– Collect primary data for
2015 Global Cotton LCA
– Support Sustainability
claims of Cotton LEADS and
Benchmark against 2008
and 2011 Surveys
– Gather grower concerns for
research prioritization
Data Integrity
•
•
•
•
925 on-line responses
818,504 upland cotton acres (approx. 10% of cotton acres)
R2 between planted acres & respondents acres was 0.90
65% requested custom analysis & provided their contact
details
• Question 25 focused on producer priorities
– Randomly presented 27 concerns selected
from 2011 survey along with new concerns
– Included two “obvious” answers to test
whether respondents read the questions
– 22 of the concerns were rated by growers as
high priority (major + moderate > 65%)
– 3 were rate low (not an issue > 65%)
and Moderate
Production
Concerns
Major &Major
Moderate
Producer
Concerns
Major Issue
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Moderate Issue
Top 12 Producer Priorities
Q25. How would you rate the following cotton
production concerns or challenges on your farm?
Cotton production input costs
Weed resistance to herbicides
Weed control
Cottonseed value
Spread of plant disease and weeds
Seedling vigor and stand establishment
Consumer attitudes about Ag’s impact on the environment
Cotton’s tolerance to heat and drought
Efficient use of fertilizer
Adequate water supply
Variety selection
Plant bug control
Major Moderate
81%
69%
64%
51%
42%
42%
40%
39%
37%
37%
34%
32%
16%
25%
31%
40%
43%
40%
38%
48%
43%
35%
43%
44%
Not an
Issue
2011
Rank
2015
Rank
3%
6%
5%
8%
14%
18%
22%
13%
20%
28%
23%
24%
1
5
4
7
New
6
31
3
19
15
2
9
1
2
3
4
5
6
7
8
9
10
11
12
Middle 10 Producer Priorities
Q25. How would you rate the following cotton
production concerns or challenges on your farm?
Climate change - rainfall & temperature
Lack of new crop protection products
Pesticide drift
Insect resistance to insecticides and Bt cotton
Soil sampling and analysis for fertilization
Monitoring cotton’s plant growth
Harvest aid materials and application timing
Stink bug control
Soil erosion
Soil compaction
Major Moderate
30%
29%
28%
28%
27%
25%
24%
23%
19%
17%
45%
49%
55%
44%
41%
49%
48%
47%
52%
57%
Not an
Issue
2011
Rank
2015
Rank
24%
22%
17%
28%
33%
26%
27%
30%
28%
26%
new
7
new
19
10
16
11
12
new
new
13
14
15
16
17
18
19
20
21
22
Top 5 Major Producer Concerns by Region
Far West:
Southwest:
Mid-South:
Southeast:
1. Input costs
2. Adequate water
supply
3. Tolerance to heat
and drought
4. Weed control
5. Herbicide resistant
weeds and (TIED)
variety selection
1. Input costs
2. Herbicide resistant
weeds
3. Weed control
4. Cottonseed value
5. Adequate water
supply
1. Input costs
2. Herbicide resistant
weeds
3. Weed control
4. Plant bug control
5. Cottonseed value
1. Input costs
2. Herbicide resistant
weeds
3. Weed control
4. Cottonseed value
5. Spread of plant
diseases and weeds
Bother learning about irrigation?
Because we can do better!
0.30
0.25
0.20
0.15
0.10
0.05
USA 4
USA 3
USA 2
0.00
USA 1
(kg fiber/m3 rain+irr.)
Water Use Efficiency
0.35
11
Grower’s Water Use Efficiency
Histogram of Irrigation Water Use Efficiency
Pounds of Fiber Above Non-Irrigated Yield per Inch of Irrigation
Water Use Efficiency Research
Cotton Water Use and Benefit at Halfway, Texas
Average Water Requirement (in/day)
Based on ETo & HU accumulation from 1978-2010 and Crop Curve Developed at Texas AgriLife Research
0.30
150 lbs/ac-in
0.20
0.10
Boll Maturation
(> 1350 hu)
May 15
Emergence
Date
Vegetative
growth
(~ < 950 hu)
0.00
1-May
Jim Bordovsky
1-Jun
1-Jul
Boll Retention
(~ 950 to 1350 hu)
1-Aug
1-Sep
50 lbs/ac-in
Decisions empowered by knowledge of
plant condition & anticipated weather
Plant condition in West Texas is easy
to assess:
• See the fruit through the leaves
• Retention almost
always excellent on
first position bolls
• Soils are generally
uniform laterally
and vertically
Decision empowered by knowledge of
plant condition & anticipated weather
Anticipating weather is much more difficult:
• Summer is relatively predictable
• Highly variable fall and spring temperatures
• Forecast improving at 1 day per decade
3-day
5-day
7-day
10-day
Science 2015 525:47
Lubbock, Texas 33°N
Urumuqi, Xinjiang 43°N
Approximately 5 nodes are buried
above the top unfolded leaf
1 leaf unfolded
5 leaves developing
1st square is a “glint in daddy’s eye”
What Does that mean for water?
1. Only cotyledons preformed in seed - no true
leaves, so lots of time needed to form leaves
2. Root rapidly expanding into moist soil
3. Water use is via surface evaporation not plant
transpiration
• Avoid wasting water to evaporation
• Avoid cooling the soil
• Evaluate soil moisture and root growth
At first square there are 6 to 8 future
bolls on the plant
• First square visible at 5 to 7 mainstem leaves
• 5 squares developing above this top square
• 75% of the bolls to be harvested already on the
plant as developing squares
What Does that mean for water?
1. Plant needs to build hidden structures
–
–
–
nodes
fruiting sites
roots
2. Hopefully some healthy leaves as well
3. Yield ~insensitive to irrigation, unless 3+ bales/acre
4. Fiber quality unaffected by irrigation
• Avoid wasting water to evaporation
• Evaluate subsoil moisture and root growth
• Irrigate severely stressed cotton to produce
adequate nodes and fruiting sites
At 1st bloom all
the fruit you will
ever harvest is on
the plant
What Does that mean for water?
1. Yield is most sensitive, because young fruit
shed easily
2. Quality is entering its most sensitive stage of
fiber elongation
3. Roots are at maximum depth & uptake
efficiency
• Don’t damage roots
• If you have water, use it now
• If you don’t, pray for rain
Bolls Add Size before Yield
• Crop termination rules focused on boll maturation
• Any one of these three runs out, the season’s over
– Water to keep leaves functioning
– Temperature to keep bolls developing
– Benefits of few, small immature bolls out weigh the yield
or quality loss of the entire crop
Fulvio R Simao
Graduate Seminar – 2011
What Does that mean for water?
1. All the bolls you’ll every harvest are full size bolls
on the plant
2. Yield is least sensitive, because:
– full size bolls don’t shed nor lose weight
– plant is only adding yield to immature bolls
3. Daily water use is half or less
• Don’t over water, no large irrigations
• Avoid lush growth that cools the plant
delays harvest and lowers leaf grades
Stress Signals
• Leaves are warm
and limp
• Mainstem growth
slows
• Leaf color dulls,
darkens then
lightens in entire
plant
• Leaf function is
damaged
• Small bolls shed
Why not play it safe and overwater?
• Expensive and limited
resource to waste
• Nitrogen loss through
leaching
• Delayed harvest
• Lower trash and bark
grades
Irrigation Research – Glen Ritchie
Irrigation Timing
• Which crop stage is most sensitive to stress?
• They conducted an experiment with 4
cultivars subjected to the following irrigation
treatments:
– No irrigation from first square to first flower
– No irrigation from first flower to 3 weeks after first
flower
– No irrigation from 3 to 6 weeks after first flower
– No irrigation from 3 to 9 weeks after first flower
– Full Irrigation
First Square to First Flower
• Severe stunting
• Fewer bolls
• 20-25% yield decrease
First Flower to FF + 3 Weeks
• Nearly full crop height
• Massive shedding
• Yields reduced by 60-70%
Peak Bloom (3 weeks)
• Yields decreased by 20-30%
• Decreased boll numbers at
the top of the plant
• Less sensitive to stress than
early bloom
Peak Bloom (6 weeks)
• Yields decreased 30-35%
• Decreased boll numbers at
the top of the plant
• Less sensitive to stress than
early bloom
Full Irrigation
100%
80%
60%
40%
20%
0%
Drought Episodes
Cultivar
Squaring
Early
Flower
Peak
Peak
Bloom (3 Bloom (6 Full
weeks)
weeks)
Irrigation
DP0912B2RF
1153
566
1123
1033
1552
DP0935B2RF
1253
545
1031
1076
1516
FM9170B2F
1184
476
1021
976
1440
FM9180B2F
1080
478
1115
1035
1345
Total lint yield per acre for different drought stress timings
Boll Distribution
Bolls per Node per Plant
1.0
Squaring
First flower
Peak bloom
for 3 weeks
Peak bloom
for 6 weeks
Full irrigation
0.8
0.6
0.4
0.2
0.0
6
8
10
12
Node
14
16
18
20
Bolls per Node per Plant
1.0
Minimal
irrigation
30% ET
60% ET
90% ET
0.8
0.6
0.4
0.2
0.0
6
8
10
12
Node
14
16
18
20
Fiber Quality: Micronaire
• Micronaire is closely tied to irrigation level in
most cases
– Related to fiber maturity (Montalvo and Holden,
2005)
– Related to fineness (Montalvo and Holden, 2005)
• Micronaire can vary from one part of the plant
to another (Bauer 2009)
Fiber Quality: Strength
• Strength appears to be controlled more by
genetics than growing environment (May,
1999)
• We will sometimes see differences in strength
between irrigation treatments for a cultivar,
but they seem to occur only under severe
stress
Fiber Quality:
Length and Uniformity
• Length
– Affected under severe deficit (if you lose 40% of
your yield or more, length will often be lower, too)
– Complex physiological interactions (Bradow and
Davidonis, 2000)
• Uniformity follows length pattern in many
cases
– More affected by temperature than length is
OBJECTIVE
Compare cotton fiber quality in eight
commercial cultivars subjected to
episodic drought periods in West Texas
in 2010.
Fulvio R Simao
Graduate Seminar – 2011
METHODS
• The experiment was conducted at the Texas Tech
New Deal Research farm.
• Split-plot experimental design with three
irrigations (main plot), 8 cultivars (split-plot), and
3 replicates (block)
• Irrigation treatments:
– Full irrigation throughout the season
– 3 weeks of non-irrigation beginning at 5 weeks after
first flower
– 6 weeks of non-irrigation beginning at 5 weeks after
first flower
Fulvio R Simao
Graduate Seminar – 2011
RESULTS
HVI STATISTICS
Table 1. p-values related to the significance of the analysis of variance for each
variable as affected by the irrigation episodic drougth, cultivar or their
interaction
Factor
Irrigation
Cultivar
Irr*Cult Interaction
Micronaire
0.0087 **
<0.0001 **
0.0413 *
Length
0.0066 **
<0.0001 **
0.0938 .
Uniformity ratio 0.4329 n.s.
0.0143 *
0.2294 n.s.
Bundle strength 0.0631 .
<0.0001 **
0.3539 n.s.
Elongation
0.4465 n.s.
<0.0001 **
0.7758 n.s.
Color Rd
0.0481 *
<0.0001 **
0.1664 n.s.
Color +b
0.5589 n.s.
<0.0001 **
0.1261 n.s.
Leaf
0.1186 n.s.
<0.0001 **
0.4764 n.s.
Fulvio R Simao
Graduate Seminar – 2011
RESULTS
MICRONAIRE
Micronaire
6
Cultivar
5.5
DP0912B2RF
5
DP0924B2RF
4.5
DP0935B2RF
DP09R555B2R2
4
DP1028B2RF
3.5
FM1880B2F
3
FM9170B2F
0
3
6
Weeks of irrigation interruption
FM9180B2F
Figure 3. Micronaire of eight cotton cultivars submitted to different
irrigation interruptions during the 2010 season at the Texas Tech
New Deal Research Farm. Black bars represent the standard
deviation.
Fulvio R Simao
Graduate Seminar – 2011
Fiber lenght (inches)
RESULTS
LENGTH
1.25
1.2
1.15
1.1
1.05
1
0.95
0.9
Cultivars
DP0912B2RF
DP0924B2RF
DP0935B2RF
DP09R555B2R2
DP1028B2RF
FM1880B2F
0
3
6
Weeks of irrigation interruption
FM9170B2F
FM9180B2F
Figure 4. Fiber length of eight cotton cultivars submitted to different
irrigation interruptions during the 2010 season at the Texas Tech
New Deal Research Farm. Black bars represent the standard
deviation.
Fulvio R Simao
Graduate Seminar – 2011
Water Stress Impacts on Cotton
Fruit stage
Fruit
Retention
Fiber Quality
Fiber Yield
Pre-square
development
Square
development
minimal
minimal
minimal
moderate
minimal
Loss
1st 30 days boll
development
severe
short staple,
high mike
Severe Loss
2nd 30 days boll
development
minimal
immature fiber
Loss
Boll opening
none
minimal
Hasten
maturity
When to hold'em
Life at depth.
During early to mid bloom
Hot, dry & windy
Shallow soil moisture
When to fold'em
Life at depth.
Run out of time,
Run out of heat units,
Run out of immature bolls
or
Prebloom when water is limited
Julie A. Huber Science 2015;349:376-377
Thank you
www.cottoninc.com