Soybean Agronomics Eric P. Prostko Department of Soil & Crop Science The University of Georgia.

Soybean Agronomics

Eric P. Prostko

Department of Soil & Crop Science

The University of Georgia

Soybean Production In Georgia – Acres Planted

0

500

1000

1500

2000

2500

3000

Year

Acr

es (X

100

0) .

Source: NASSSource: NASS

430

Soybean Production In Georgia – Yield

0

5

10

15

20

25

30

35

Year

Bu/A

.

Source: NASSSource: NASS2000-2008 = 27.562000-2008 = 27.561990-1999 = 23.201990-1999 = 23.201980-1989 = 21.401980-1989 = 21.40

Soybean Production In Georgia – Average Price

0

2

4

6

8

10

12

14

Year

$/B

u .

Source: NASSSource: NASS2000-2007 = 6.462000-2007 = 6.461990-1999 = 5.891990-1999 = 5.891980-1989 = 6.081980-1989 = 6.08

General Production Practices - I

• Crop rotation– Soybeans or other legumes once every 2 years

– CBR (peanuts) = Red crown rot (soybeans)

• Soil Fertility Issues– pH = 6.0

– Fertilize according to soil test results

– 40 bu/A soybeans will use 38 lbs/A P2O5 and 144 lbs/A K2O

– Use inoculant if soybeans have not been planted in last 3 years

• Soybeans = Bradyrhizobium japonicum

General Production Practices - II

• In-row sub-soiling in Coastal Plain region

• Planting Date– Optimum: May 10-June 10

– Late: June 11-June 30

– Avoid planting Group V after June 15

• Row Spacing– 15-36”

Row Spacing Effects on Soybean Yield In Georgia

• Carter and Boerma, 1979 (Athens, GA)

– 38” to 19” = 11% yield increase

• Boerma and Ashley, 1982 (Plains, GA)


• Ethredge et al., 1989 (Plains, GA)




• Woodruff, 2007-2008 (Camilla, GA)


Washington County, GA (2008)

What about twin row soybeans?

• No Georgia data available.

• LSU trials indicated that twin rows outyielded single rows by 9%.

• MSU trials indicated that twin rows outyielded single rows by 10%.

• In Texas, twin rows outyielded single rows by 11%

• Will twin rows produce higher yields than narrow single rows??

General Production Practices - III

• Seeding Rate– May-Early June – 145,000 seed/Acre

• 36” rows = 10 seed/ft• 15” rows = 4 seed/ft

– Late June – 160,000 seed/A• 36” rows = 11 seed/ft• 15” rows = 4.6 seed/ft

• Planting Depth– 1”-1.25” deep

• UGA Recommended Varieties

What Group should you plant?

• UGA OVT Results

• 2001-2007 (7 years)

• Planted in early May

• Irrigated

• Six locations– Athens, Calhoun, Griffin,

Midville, Plains, Tifton

51.2 50.3 49.8

0

15

30

45

60

V VI VII,VIII

Maturity Group

Bu/A

.

Planting Early and Late Maturing Varieties Can Spread Drought Risks and Optimum Harvest Time

2008 UGA OVT ResultsGroup V – May PlantingTop 5 Yielding Varieties

Tifton Plains Midville Griffin Athens Calhoun

RT5951N RT5930N P95Y20 Progeny

5650RR

AGS

568RR

RT5760N

AG5905 Progeny 5650RR

RT5160N RT5760N Progeny

5650RR

Progeny

5650RR

P95Y20

Progeny 5706RR

Progeny 5622RR

AG5905 RT5960 Progeny

5622RR

UGA G03-1668RR

Progeny

5650RR

Dynagro

33X55

RT5930N AGS

568RR

UAK R0-976

RT5930N

UAK R0-976

UGA G03-1668RR

Progeny

5650RR

Progeny

5622RR

USG 7582nRR

RT5540N

2008 UGA OVT ResultsGroup VI – May PlantingTop 5 Yielding Varieties


UAK R01-327

RT6207RR AG6702 RC 6298 RC 6298 UAK R03-1232

Musen AG6301 UAK R31-1134

V61N9RR UAK R01-327

UAK R31-1134

UAK R31-1134

USG 7635nRR

UAK R03-1232

AG6301

UAK R01-327

RT6988N DKB64-51

USG 7635nRR

USG 76S17

RT6600N NKS61-Q2 DKB64-51 AGS

606RR

USG 620nRR

RC 6298 AGS

606RR

UAK R03-1232

AG6702 USG 76S17

2008 UGA OVT ResultsGroup VII/VIII – May PlantingTop 5 Yielding Varieties


V76N9RR V72N7RR UGA G00-3209

(Woodruff)

- UGA G00-3209

(Woodruff)

-

AG7502 USG 77U28

UGA G04-2414RR

- UGA G03-1187RR

-

UGA G04-1618RR

NKS78-G6 AG7501 - UGA G04-1618RR

-

UGA G00-3209

(Woodruff)

UGA G04-1618RR

USG 7732nRR

- USG 77S27

-

UGA G04-2215RR

Progeny

7208RR

RT 7355N - NKS78-G6 -

General Production Practices - IV

• Control Weeds

• Control Insects– Boron (0.25-0.5 lb/A) + Dimilin (2-4 oz/A) at R2-R3 stage –

Coastal Plain Region

• Control Soybean Rust if needed

R2

R3

Strobi Fungicides will cause green stem/leaf phenomenon

QuadrisQuadris DomarkDomark

Early Soybean Production Systems

• Planting Date: April 30-May 10• Harvest Date: Mid-September• MG IV or early V varieties (indeterminate)

– Pioneer 94M80 (RR), Southern States RT4808N (RR/STS), Southern States RT 5160N (RR)

• 15-30” row spacing• Increase seeding rates by 10-20%• Concerns

– stink bugs at early pod-fill (July)

– seed quality/shatter at maturity (timely harvest)– August/September hurricanes

2008 Early System Soybean Trial – Sunbelt Ag Expo

• Planting date: April 25• Seeding Rate: 175,000/A

– 6/row foot

• Row Spacing: 18”• Plot Size: 0.365-0.874 A• 3 replications• Fertility: 2 tons/A chicken litter• Irrigated• Fungicides: Headline (2x)• Insecticides:

– Boron + Dimilin– Stinkbugs

• Harvest Date: September 10• Trial conducted by Dr. John Woodruff

78 75 77

0

16

32

48

64

80

SSRT4808

P 94Y80 SSRT5160

Variety

Bu/A

.

P = 0.6597P = 0.6597CV = 4.17CV = 4.17

Soybean Irrigation

• Soybeans will produce ~ 2 bu/A for every 1” of water use.– 40-50 bu/A = 20-25” water

• Water Use by Stage (in/day)– Germination/Seedling = 0.05-0.01”– Vegetative = 0.10-0.20”– Flower to Pod Fill = 0.25-0.35”– Maturity to Harvest = 0.05-0.20”

• When to stop?– Pod-fill (R6)– 50+% of pods– green seed touching in pod

2007-2008 Soybean Irrigation Study

• Stripling Irrigation Research Park (Camilla)

• Varieties (2)– AGS 568– AGS 758

• Row Spacing (2)– 24” or 36 “

• Irrigation (4) (KanSched)– None (except emergence)– 60% irrigation all season– 120% irrigation all season– 60% irrigation during vegetative

growth, 120% irrigation during reproductive growth

2007-2008 Soybean Irrigation Study - Results

• No interaction between year, variety, row spacing, irrigation

• AGS 568 = AGS 758– 65.2/63.6 Bu/A

• 24” > 36” (8%)– 66.9 vs. 62.0 Bu/A

• Irrigation > dryland by 12.5% but no differences in yield between schedules

Irrigation vs DrylandStripling (2007-08) - Yield

5967 66 66

0

15

30

45

60

75

Dryland 60% 120% 60/120%

System

Bu/

A .

bbaa aa aa

Averaged over 2 years, 2 varieties, and 2 row spacings.Averaged over 2 years, 2 varieties, and 2 row spacings.

Irrigation vs DrylandStripling (2007-08) – Cost/Bu

6.647.73 7.92 7.88

0

2

4

6

8

10

Dryland 60% 120% 60/120%

System

$/B

u .

Averaged over 2 years, 2 varieties, and 2 row spacingsAveraged over 2 years, 2 varieties, and 2 row spacingsVariable + Fixed CostsVariable + Fixed Costs

Irrigation vs DrylandStripling (2007-08) – Net Return

139.24

85.0971.28 73.92

0

25

50

75

100

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150

Dryland 60% 120% 60/120%

System

Net

Ret

urn

($/A

) .

Averaged over 2 years, 2 varieties, and 2 row spacingsAveraged over 2 years, 2 varieties, and 2 row spacings$9.00/Bu$9.00/Bu

Stripling Irrigation Research ParkRainfall 2007-2008

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3

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15

May June July Aug Sept Oct

Month

In .

Average 2007 2008

Source: Georgia Automated Environmental Monitoring Network

2009 Soybean Production Guide – Minor Editions

• 2008 UGA OVT Results (pages 109-128)

• MG VI– JGL EXP862 = Croplan Genetics RC 6298

• MG VII & VIII– Pioneer 95Y11 = Pioneer 98Y11

UGA Soybean Web-Pagehttp://www.gasoybeans.uga.edu

Soybean Agronomics Eric P. Prostko Department of Soil & Crop Science The University of Georgia.

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