Phosphorus Nutritionof Cotton

Outline - P Nutrition of Cotton

• U.S. cotton yields since 1975

• Growth and developmentof the cotton plant

• Nutrient uptake

• General P nutrition andresponse

• P placement options

• Conclusions

U.S. Cotton Yield,1975 to Present . . . An Increasing Trend

300

350

400

450

500

550

600

650

700

750

Lint, lb/A

Year

Source: USDA-NASS

Source: R. Boman

Approximate days after planting

Approximate heat units after planting

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160

Emergence Squaring Peak bloom Harvest1st bloom 1st open boll

May June July August September NovOctober

0 80 525 1060 1470 1640 2280

95% mature

A Production Timeline for Irrigated Cotton in the Texas High Plains

Early Season Root Development of the Cotton Plant

Source: Oosterhuis, 1990

Cotton Root Length as Affected by Days After Planting (Field Study)

Source: Schwab, Mullins & Burmester, 2000

Roots, ft/plant

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

0 37 49 64 87 99 112 122 134 151Days after planting

4 true leaves

First bloom

Late bloom/early boll filling

Based on 36,000 plants/A, there were 9,545 miles of roots /A

Dry Matter Accumulation,and Nitrogen andPhosphorus Uptake of Cotton

Time (Days)

0 30 60 90 120 150

Ma

xim

um

Accu

mu

latio

n (

%)

0

20

40

60

80

100 Dry weight and phosphorus

Nitrogen

* First Square

* First Flower

* Peak Bloom

* First open boll

* 20% open boll

* 50% open boll

Source: D. Krieg

Cotton Nutrient Uptake Compared to Yield

* Irrigated tests

Where – Who Year Cotton Type Lint Yield (lb/A) N P2O5 K2O

- - lb per 100 lbs. of lint - -

GA-Olson 1942 Upland 760 18 8 18

CA - Bassett* 1970 Acala 1,450 10 3 11

Israel - Halevy* 1976 Acala 1,580 14 6 12

AL - Mullins 1990 Upland 880 20 6 18

LA - Breitenbeck 1993 Upland 1,230 14 6 13

AZ – Unruh* 1996 Upland 1,186 15 5 23

1996 Pima 965 21 7 25

Removal in harvested crop

IPNI 6.7 2.9 4.0

Cotton Peak Nutrient Uptake Rate 60 to 100 Days After Planting

Source: Mullins and Burmester, 1990

GA *CA *Israel AL

1942 1970 1976 1990

N 3.8 1.8 4.1 3.5

P 0.7 0.3 0.8 0.6

K 2.5 3.0 4.1 3.1

* Irrigated tests

lb/A per day

Location and year

P Functions of Phosphorus in Cotton Production

• Essential for vigorous root and shoot growth

• Promotes early boll development and hastens maturity

• Helps overcome the effects of compaction

• Increases water use efficiency• Necessary for energy storage and

transfer in plants• A two-bale crop can take up more

than 50 lb P2O5/A

P Uptake by Modern Cotton Varieties – 880 lb/A

0

5

10

15

20

0 21 35 49 63 77 91 105 119

Days after planting

P,

lb/A

Shoots Leaves Burs Seed

Averaged across four varietiesDeltapine 90, Stoneville 825, Coker 315, Paymaster 145

Source: Mullins & Burmester, 1990

P Compartmentation by Developing Cotton Bolls

0

5

10

15

20

25

30

35

40

0 10 14 21 28 35 42 49 56

P, mg

Days After Pollination

Seed

Bur (x 2)

Fiber (x 2)

Mature boll oven-dry weight ~ 6.5 grams

Source: Leffler, H.R. 1986

Reasons to BuildSoil Test P

• Increase root growth for efficient uptake of other nutrients

• Capitalize on “good weather” years• Minimize risk associated with “bad weather” years• Raise soil productivity• Increase yield potential of all crops in the rotation• Improve grower profit potential• Rules of thumb for raising soil test P

– 6 to 14 lb P2O5 needed above crop removal to build soil test P by 1 lb/A on sandy loam to silt loam soils

Probability of a Phosphorus Response . . . An Example

Soil test P, Probability of

category response

Very low > 80% Low 60-80%

Medium 40-60% High 20-40%

Very high < 20%

Category definitions vary among laboratories

Source: Cox, F.R. and J.S. Barnes, 2002

Cotton Relative Yield Response to Mehlich 3 Soil Test P in North Carolina

0

20

40

60

80

100

120

0 10 20 30 40 50 60 70 80 90 100

0 to 8-inch Mehlich 3-P, ppm

Soil test for 95% of maximum yieldR

ela

tiv

e y

ield

, %

6-Year Average Cotton Response to P Rate and Tillage in Tennessee

700

800

900

1,000

1,100

1,200

0 40 80 120

Disk Till No-till

lb P2O5/A per year

Lint, lb/A

Low initial soil P

Source: Howard & others, 2001

Soil P Levels After 3 Years of P Fertilization on loessial Silt Loam Soil in Tennessee

Source: Howard & others, 2001

0

5

10

15

20

25

30

35

40

0 40 80 120

DT-1997

DT-1998

DT-1999

NT-1997

NT-1998

NT-1999

Mehlich 1 P, ppm at 0 to 6 in. depth

lb P2O5/A per year

Tillage & Year

DT=Disk-tillNT=No-till

P Placement Options

• Broadcast• Banded 2 x 2 (2 in. to the side and 2 in. below seed)• Surface banded• Deep banded• In-furrow with the seed (rates are limited due to possible

seedling damage and toxicity)– Rates of 11-37-0 greater than 2.5 to 2.8 gal/A have been

shown to reduce cotton stands and yield, and rates greater than 1.5 gal/A are not recommended (Burris et. al., 1992)

Effects of P Placement on Relative Cotton Yield

Source: Nelson & others, 1949. See notes for application methods

lb P2O5/A applied and placement method

5060708090

100

Low P soil(29 lb/A extractable P)

Relative yield, %

bab

a aa a

5060708090

100

High P soil(126 lb/A extractable P)

Relative yield, %

No significant differences

Effects of P Placement on Relative Cotton Root Length (Laboratory study)

Source: Mullins, 1993

Applied P per pot was identical within a soil

Low P Dewey soil (CEC=10)14 lb/A (7 ppm) Mehlich 1-P

2030405060708090

100

0 12.5 25 50 100

Percent of soil volume fertilized

Relative total root length %

b

a aa a

50

60

70

80

90

100

0 12.5 25 50 100

Percent of soil volume fertilized

High P Marvyn soil (CEC=5)88 lb/A (44 ppm) Mehlich 1-P

Relative total root length, %

No significant differences

Effects of P Placement on Percent of Roots in Fertilized Soil (Laboratory study)

Applied P per pot was identical within a soil

Low P Dewey soil (CEC=10)(14 lb/A Mehlich 1-P)

0

20

40

60

80

100

0 12.5 25 50 100

Percent of soil volume fertilized

% of roots in P-treated volume

0

20

40

60

80

100

0 12.5 25 50 100

Percent of soil volume fertilized

High P Marvyn soil (CEC=5)(88 lb/A Mehlich 1-P)

% of roots in P-treated volume

Source: Mullins, 1993

Effect of In-furrow Starter Fertilizer on Cotton Yield (Louisiana)

Source: Kovar et. al., 1993.

In-furrowYear Soil texture Check Starter Difference

1990 Silt loam 1255 1400 145*

1991 Silt loam 1184 1191 7

1991 Silt loam 1503 1586 83*

1992 Silt loam 878 889 111992 Silt loam 922 911 -11

1992 Silt loam 999 1040 41

1992 Clay 515 697 182*1992 Silt loam 734 837 103*

1993 Silt loam 941 1174 233*Average 992 1081 88

* Differences were significant a the 0.05 level of probability.11-37-0 starter was applied at the rate of 1.5 gal/A.All soils tested high to very high in P.

lint yield, lb/A

Effect of Surface Banded Starter Fertilizer on Cotton Yield (Louisiana)

SurfaceYear Soil texture Check banded Difference

1990 Silt loam 1,255 1,443 188*1990 Silt loam 823 895 721990 Silt loam 1,045 1,032 -131991 Silt loam 1,184 1,331 147*1991 Silt loam 949 1,073 124*1992 Silt loam 999 1,144 1451992 Silt loam 878 957 79*1993 Silt loam 860 969 109*

Average 999 1,106 106* Differences were significant a the 0.05 level of probability.11-37-0 starter was applied in a 3 inch surface band at the rate of 12 gal/A.All soils tested high to very high in P.

lint yield, lb/A

Source: Kovar et. al., 1993.

Effects of Fertilizer Placement on Cotton Seedling Growth (Louisiana)

Source: Kovar et. al., 1993. High soil test P level

Check 12 gal/A 11-37-0surface banded

1.5 gal/A 11-37-0in-furrow

Effect of Starter Fertilizer (11-37-0) on Cotton Root Length Density (Louisiana)

Seedling

Ro

ot

len

gth

den

sity

, cm

/cm

3

------- Early bloom -------

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

0-4 inch 0-4 inch 4-8 inch

Check Surf. band (12 gal/A)In-furrow (1.5 gal/A) In-furrow (2.5 gal/A)

Source: Kovar et. al., 1993. High soil test P level

Effect of P Fertilizer and Delivery Method on three-year Average Irrigated Cotton Yield (Texas)

Source: Reiter and Krieg - Means with same letter are not different at the 5% level

c818

b916

c824

a972

0

200

400

600

800

1000

Control Pre-plant Sidedress LEPAfertigation

P fertilizer application method

Lin

t yi

eld

, lb

/A

P Fertilizer and Delivery Method effect on BollNumber in Irrigated Cotton (Texas)

P fertilizer application method

10

20

30

40

50

60

Control Pre-plant Sidedress LEPAfertigation

Bo

lls p

er s

q. m

53 5751

58

0

Source: Reiter and Krieg

Effect of P Fertilizer and Delivery Method on Boll Size in Irrigated Cotton (Texas)

1.54 1.58 1.61.66

1

1.1

1.2

1.3

1.4

1.5

1.6

1.7

Control Pre-plant Sidedress LEPAfertigation

P fertilizer application method

Lin

t p

er b

oll,

g

Source: Reiter and Krieg

Effect of P Fertilizer and Delivery Method on Micronaire of Irrigated Cotton (Texas)

P fertilizer application method

Mic

ron

aire

20

25

30

35

40

45

Control Pre-plant Sidedress LEPAfertigation

35.6

39.3

36.6

39.7

Premium range 37-42

Source: Reiter and Krieg

Conclusions

• Adequate P nutrition is critical in optimizing yield, quality, and profit in cotton production.

• While placement of P fertilizer is not as important as in the production of many other crops, banding P can increase yields in some situations (e.g., reduced or no-till, compacted soil conditions).

• Soil test levels should be maintained in the medium to high range to assure consistent production, and that P does not limit cotton yield and quality.

International Plant Nutrition Institute (IPNI) 655 Engineering Drive, Suite 110Norcross, GA 30092-28326047Phone: 770-447-0335; Fax: 770-448-0439E-mail: info@ipni.net

Reference 06128