Soybean
Agronomics
Eric P. Prostko
Department of Soil & Crop Science
The University of Georgia
Soybean Production In
Georgia – Acres Planted
3000
.
2500
Acres (X 1000)
2000
1500
1000
430
500
Year
Source: NASS
20
08
20
06
20
04
20
02
20
00
19
98
19
96
19
94
19
92
19
90
19
88
19
86
19
84
19
82
19
80
0
Soybean Production In
Georgia – Yield
35
30
.
25
Bu/A
20
15
10
5
20
08
20
06
20
04
20
02
20
00
19
98
19
96
19
94
19
92
19
90
19
88
19
86
19
84
19
82
19
80
0
Year
Source: NASS
2000-2008 = 27.56
1990-1999 = 23.20
1980-1989 = 21.40
Soybean Production In
Georgia – Average Price
14
12
.
10
$/Bu
8
6
4
2
20
08
20
06
20
04
20
02
20
00
19
98
19
96
19
94
19
92
19
90
19
88
19
86
19
84
19
82
19
80
0
Year
Source: NASS
2000-2007 = 6.46
1990-1999 = 5.89
1980-1989 = 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)
– 36” to 20” = 17% yield increase
•
Ethredge et al., 1989 (Plains, GA)
– 30” to 20” = 8% yield increase
– 30” to 10” = 11% yield increase
– 20” to 10” = 3% yield increase
•
Woodruff, 2007-2008 (Camilla, GA)
– 36” to 24” = 8% yield increase
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?
– Athens, Calhoun, Griffin,
Midville, Plains, Tifton
60
.
UGA OVT Results
2001-2007 (7 years)
Planted in early May
Irrigated
Six locations
45
Bu/A
•
•
•
•
•
30
51.2
50.3
49.8
V
VI
VII,
VIII
15
0
Maturity Group
Planting Early and Late Maturing Varieties Can
Spread Drought Risks and Optimum Harvest Time
2008 UGA OVT Results
Group V – May Planting
Top 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 G031668RR
Progeny
5650RR
Dynagro
33X55
RT5930N
AGS
568RR
UAK R0976
RT5930N
UAK R0976
UGA G031668RR
Progeny
5650RR
Progeny
5622RR
USG
7582nRR
RT5540N
2008 UGA OVT Results
Group VI – May Planting
Top 5 Yielding Varieties
Tifton
Plains
Midville
Griffin
Athens
Calhoun
UAK R01327
RT6207RR
AG6702
RC 6298
RC 6298
UAK R031232
Musen
AG6301
UAK R311134
V61N9RR
UAK R01327
UAK R311134
UAK R311134
USG
7635nRR
UAK R031232
AG6301
UAK R01327
RT6988N
DKB64-51
USG
7635nRR
USG
76S17
RT6600N
NKS61-Q2
DKB64-51
AGS
606RR
USG
620nRR
RC 6298
AGS
606RR
UAK R031232
AG6702
USG
76S17
2008 UGA OVT Results
Group VII/VIII – May Planting
Top 5 Yielding Varieties
Tifton
Plains
Midville
Griffin
Athens
Calhoun
V76N9RR
V72N7RR
UGA G003209
(Woodruff)
-
UGA G003209
(Woodruff)
-
AG7502
USG
77U28
UGA G042414RR
-
UGA G031187RR
-
UGA G041618RR
NKS78-G6
AG7501
-
UGA G041618RR
-
UGA G003209
(Woodruff)
UGA G041618RR
USG
7732nRR
-
USG
77S27
-
UGA G042215RR
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
R3
R2
Strobi Fungicides will cause
green stem/leaf phenomenon
Quadris
Domark
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
80
– 6/row foot
•
•
64
75
77
P 94Y80
SSRT
5160
.
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
48
Bu/A
•
•
•
•
•
•
•
78
32
16
0
SSRT
4808
Variety
P = 0.6597
CV = 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 Dryland
Stripling (2007-08) - Yield
75
67
66
66
a
a
a
60%
120%
60/120%
60
.
59
Bu/A
45
b
30
15
0
Dryland
System
Averaged over 2 years, 2 varieties, and 2 row spacings.
Irrigation vs Dryland
Stripling (2007-08) – Cost/Bu
10
.
8
$/Bu
6
7.73
7.92
7.88
60%
120%
60/120%
6.64
4
2
0
Dryland
System
Averaged over 2 years, 2 varieties, and 2 row spacings
Variable + Fixed Costs
.
150
Net Return ($/A)
Irrigation vs Dryland
Stripling (2007-08) – Net
Return
125
139.24
100
75
85.09
50
71.28
73.92
120%
60/120%
25
0
Dryland
60%
System
Averaged over 2 years, 2 varieties, and 2 row spacings
$9.00/Bu
Stripling Irrigation Research Park
Rainfall 2007-2008
Average
2007
2008
15
.
9
In
12
6
3
0
May
June
July
Aug
Month
Source: Georgia Automated Environmental Monitoring Network
Sept
Oct
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-Page
http://www.gasoybeans.uga.edu