soybean. soybean growth stages vegetative stagesreproductive stages ve – emergencer1 – beginning...

Soybean

Soybean Growth StagesVegetative Stages Reproductive Stages

VE – emergence R1 – beginning bloom

VC – cotyledon (unrolled unifoliolate leaves)

R2 – full bloom

V1 – first trifoliolate* R3 – beginning pod

V2 – second trifoliolate R4 – full pod

V3 – third trifoliolate R5 – beginning seed

V(n) – nth trifoliolate R6 – full seed

R7 – beginning maturity

R8 – full maturity

When staging a soybean field , each specific V or R stage is defined only when 50% or more of the plants in the field are in or beyond that stage.

* A fully developed trifoliolate leaf node has unrolled leaflets.

Young Soybean Plant (Seedling)

Development and timing of vegetative growth, flowering, pod development, and seed filling.

Days of R Stages

R Stage

(node and leaf development)

VEVEVEVE

VE (Emergence) = Cotyledons above the soil surface.

VE

VC

V1

• Soybean seed begins germination by absorbing ~50% of its weight in water.

•Although soybean can germinate at minimum temperature of 50°F (or less), field emergence is more rapid (~7 days) and uniform if soil temperature is above 65°F.

V2V2 = Two fully developed trifoliolate leaf nodes

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• Rhizobia bacteria have infected roots and nodules become visible shortly after VE.

• N-fixation begins at V2 to V3 stages.

•Lateral roots are growing rapidly into the top 6 inches of soil.•Lateral roots are growing rapidly into the top 6 inches of soil.

Root Nodules(including a sliced nodule)

Root showing nodules

Active nodules have an internal pink color

Active nodules have an internal pink color

NodulesNodules

R1 – Beginning BloomR1 = One open flower at any node on the main stem.

Indeterminate varieties:At R1, plants are in the V7 to V10 stage. Flowering begins on the third to sixth node (depending on V stage at flowering) and progresses upward and downward.

Vegetative growth continues after flowering begins. At R1, less than half of the nodes on the main stem have developed and plants have achieved less than half their final height.

Flowers are purple or white (variety)

Open Flower

R1 – Beginning BloomR1 = One open flower at any node on the main stem.

Determinate varieties:Vegetative growth is complete before flowering begins. Most or all of the nodes on the main stem have developed and plants grow very little in height after R1.

Flowering occurs at the same time in the top and bottom of the plant. R1 and R2 may occur simultaneously.

Flowers are purple or white (variety)

Open Flower

R2 – Full BloomR2 = Open flower at one of the two uppermost nodes on the main stem with a

fully developed trifoliolate leaf node.

The rapiddry weight accumulation initially starts in the vegetative plant parts but then gradually shifts to the pods and seeds between R3 and R6.

50% defoliation at R2 reduces yield about 6 percent.

R2 marks the beginning of a period of rapid and constant (linear) dry weight accumulation by the whole plant which continues until shortly after the R6 stage.

TIME

DRY WEIGHT

g/m2

Vegetative Biomass

Tota

l Bio

mas

s

Seed

Bio

mas

s

Vegetative Stage Seed Fill

Floweringand

Seed Set

PhysiologicalMaturity

Harvest Maturity

Growth and Development of a Crop Commodity

Source: Dennis Egli

R4 – Full PodR4 = Pod is 2 cm (¾ inches) long at one of the four uppermost nodes on the main

stem with a fully developed trifoliolate leaf node.

R4 is start of the most critical period for yield determination.

From R4 through R6, stress (moisture, light, nutrients, frost, lodging, defoliation) reduces yield more than any other period.

Yield reductions at R4 result mainly from fewer pods per plant.

Stress can cause pods to abort.

Period of rapid dry weight accumulation by the pods (R4 to middle of R5).

¾ inchlong pod

R4 – Full Pod

R4 is start of the most critical period for yield determination.

From R4 through R6, stress (moisture, light, nutrients, frost, lodging, defoliation) reduces yield more than any other period.

Yield reductions at R4 result mainly from fewer pods per plant.

Stress can cause pods to abort.

Period of rapid dry weight accumulation by the pods (R4 to middle of R5).

R6 – Full Seed

Dry weight accumulation still rapid in seeds, but begins to slow shortly after R6.

R6 = Pod containing a green seed that fills the pod cavity at one of the four uppermost nodes on the main stem with a fully developed trifoliolate leaf node.

“green bean” stage

Stress reduces seed size (weight)

Sequence of Seed Development (R5 R6)

R5R5R6R6

R5 = Seed is 3 mm (1/8) long

R6 = Green seed fills pod cavity

Soybean Pods and Seeds (R6 R8)

(R8)

(R7)

(R6)

Components of Soybean Yield

• Soybean yield is determined by 3 major components.– Number of pods per plant.– Number of seeds per pod.– Weight per seed (seed size).

University of Kentucky

Soybean: High Yields

University of KentuckyChad Lee © 2007 19

Keys to High Yields

1. Good genetics

2. Maximize days suitable for growing

3. 90 to 95% light interception at flowering (R1) through beginning seed (R5)

4. Adequate nutrients

5. Adequate, timely water and air

University of KentuckyChad Lee © 2007 20

HABITS1. Select fields to plant to soybean2. Rotate crops3. Tillage (minimal): deep ripping, if necessary; no-till

where possible4. Select high-yielding varieties5. Fertilize to soil test and inoculation (if needed)6. Timely planting (full season)7. Narrow rows (15 inches or less)8. Lower seeding rates (100,000 final stand)9. Effective, timely pest control10. Monitor stands

University of KentuckyChad Lee © 2007

Soybean: Crop Rotation

• Continuous soybean: about 5 to 10% lower yields than soybean following corn


Variety Selection

• Are you buying for yield?


More2007 2006 Favorable Potent. Price Potential

Rank of Variety UKSPT2 Variety2 Diff. Acres Addnl. per RevenuePlanted1 MG Bu./A Bu./A Bu./A Planted1 Bu. Bu.4 Lost

1. Pioneer 94M80 L4 56.6 60.5 3.9 92,000 358,800 $9.00 $3,229,200 2. NK S49-Q9 L4 60.2 60.5 0.3 75,900 22,770 $9.00 $204,930 3. Asgrow AG4703 L4 58.8 60.5 1.7 56,350 95,795 $9.00 $862,155 4. Pioneer 94B73 L4 58.5 60.5 2.0 47,150 94,300 $9.00 $848,700 5. Pioneer 94M30 E4 58.4 60.5 2.1 44,850 94,185 $9.00 $847,665 6. Southern Cross Michael E4 57.6 60.5 2.9 40,250 116,725 $9.00 $1,050,525 7. Asgrow AG4903 L4 59.0 60.5 1.5 34,500 51,750 $9.00 $465,750 8. Asgrow AG3906 3 59.5 0.0 0.0 33,350 0 $9.00 $0 8. Vigoro V48N7RS L4 NIT3 ? 33,350 ? $9.00 ? 9. Pioneer 94M50 E4 60.3 60.5 0.2 32,200 6,440 $9.00 $57,96010. NK S43-B1 E4 57.9 60.5 2.6 27,600 71,760 $9.00 $645,840 45% 517,500 912,525 $9.00 $8,212,725

100% 1,150,000 $9.00

1 Data from the 2007 Kentucky Agricultural Statistics Service (Data provided every 3 years)2 Data from the 2006 University of Kentucky Soybean Performance Tests Recommended Table (Data provided anually)3 Not in the 2006 test4 Data from the 2007 Kentucky Agicultural Statistics Service (Data provided annually)5 Data from the 2007 University of Kentucky Soybean Performance Tests Recommended Table

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Based on Yields from 2006 Trials and expected performance in 2007.(The 2006 Soybean Performance Trial was predicting yields for 2007)


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More2007 2007 Favorable Proj. Price Projected

Rank of Variety UKSPT Variety Diff. Acres Addnl. per RevenuePlanted1 MG Bu./A5 Bu./A5 Bu./A Planted1 Bu. Bu.4 Lost

1. Pioneer 94M80 L4 34.4 42.2 7.8 92,000 717,600 $9.00 $6,458,400 2. NK S49-Q9 L4 33.9 42.2 8.3 75,900 629,970 $9.00 $5,669,730 3. Asgrow AG4703 L4 40.5 42.2 1.7 56,350 95,795 $9.00 $862,155 4. Pioneer 94B73 L4 44.4 0 0 47,150 0 $9.00 $0 5. Pioneer 94M30 E4 43.2 0 0 44,850 0 $9.00 $0 6. Southern Cross Michael E4 39.3 40.4 1.1 40,250 44,275 $9.00 $398,475 7. Asgrow AG4903 L4 39.5 42.2 2.7 34,500 93,150 $9.00 $838,350 8. Asgrow AG3906 3 39.7 0 0 33,350 0 $9.00 $0 8. Vigoro V48N7RS L4 40.6 42.2 1.6 33,350 53,360 $9.00 $480,240 9. Pioneer 94M50 E4 43.8 0 0 32,200 0 $9.00 $0 10. NK S43-B1 E4 N.I.T. ? 27,600 ? $9.00 ? 517,500 1,634,150 $9.00 $14,707,350

(Based on performance in 2007.)


Large Strip Trials, Populations

Hardin County, 2006Hardin CountyReplicated strips 50K, 100K and 150K seeds/acre3.9 maturity, full seasonBob Wade, Jr., Back Forty Farms


Previously Recommended Seeding Rates

Row Width (inches)

Seeding Rate

(seeds/acre)

7 119,000 - 179,000

15 139,000 – 167,000

30 111,000 – 139,000

AGR-130 SOYBEAN PRODUCTION IN KENTUCKY PART III: PLANTING PRACTICES AND DOUBLE CROPPING James H. Herbek and Morris J. Bitzer, Department of Agronomy


Cost of Soybean Populations

Population RR Seed

(seeds/acre) (bu/acre) ($/acre)

100,000 0.56 20

120,000 0.67 24

150,000 0.83 30

180,000 1.00 36

200,000 1.11 40

Assuming 3,000 seeds per pound$30 per 50 lb bag (RR Seed)


34,800

121,800

17,400

70,000

192,000

1 2

3 4

5


Minimum plant densities required for optimum yield

Seeding Date Cultivar MaturityMinimum Plant

Population1

plants/acre

24 April 03 full season Stressland 4.5 42,500

24 April 03 full season CF 461 4.6 53,400

24 April 03 full season CF 492 4.9 49,800

21 May 04 full season B283 2.8 92,300

21 May 04 full season B336 3.3 72,100

21 May 04 full season CF461 4.6 85,800

21 June 04 late B283 2.8 91,400

21 June 04 late B336 3.3 93,1001 Exponential rise to maximum, 3 parameter model: density required for 95% of yield that was achieved at maximum plant density.

Lexington, KY, 2003 and 2004


Population Effect on YieldDry Weather, 2005

Full Season

Full Season

Late Planting

Late Planting

B283 B336 B283 B336

Population Yield Yield Yield Yield

(seeds/acre) Bu/Acre Bu/Acre Bu/Acre Bu/Acre

17,400 17.1 23.9 27.1 28.8

34,800 23.9 35.5 33.4 33.6

70,000 15.6 35.5 38.0 38.7

121,800 16.3 35.6 49.4 44.3

192,000 12.0 31.2 50.1 46.5U.K. Spindletop FarmLexington, KY3 replications2005 Growing Season


Soybean Population Study(Princeton UKREC, 2005)

Seeding Rate(viable seeds/A)

Avg. Final Stand*(Plants/A)

Soybean Yield**(Bushels/A)

50,000 45,000 73 a

75,000 65,000 72 a

100,000 85,000 75 a

125,000 110,000 73 a

150,000 130,000 74 a

175,000 150,000 74 a

200,000 175,000 74 a

225,000 195,000 72 a

*Avg. approx. final stand of two varieties.**Avg. of two varieties (3.9 RM and 4.7 RM). Varieties were not significantly different.• Planted May 25, 2005. Row spacing = 15 inches.


Light Interception: Soybeans

Shibles and Weber, 1965 (Fig. 2.3 in in Gardner et al. 1985. Physiology of Crop Plants)


Light Interception:Soybean Plant Density

Fig. 2, Purcell et al. 2002. Crop Sci. 42: 172-177.

Fig. 2. Fraction of light intercepted at 11, 22, and 46 d after emergence (DAE) was regressed against population density for ‘Manokin’ (MG IV) soybean at Fayetteville, AR, in 1999, using a monomolecular model .

Arkansas (36°5' N)

81,000 162,000


KentuckyPredicted Number of Days to First Flowering

0

10

20

30

40

50

60

70

4/28 5/8 5/18 5/28 6/7 6/17 6/27 7/7

Planting Date

Day

s

MG II

MG III

MGIV

MGV

Average of 29 years of weather data, Spindletop Farm, Lexington, KY.Standard deviation: measurement of variation, expressed by bars.Flowering dates generated from CROPGRO and verified from field data by Dr. Dennis Egli.


Large Strip Trials, Populations

Hardin County, 2006Hardin CountyReplicated strips 50K, 100K and 150K seeds/acre3.9 maturity, full seasonBob Wade, Jr., Back Forty Farms


Hardin CountyReplicated strips 50K, 100K and 150K seeds/acre3.9 maturity, full seasonBob Wade, Back Forty Farms

52K

150K

100K

55.7 bu/a55.7 bu/a 53.3 bu/a53.3 bu/a

55.6 bu/a55.6 bu/a

Hardin CountyReplicated strips 50K, 100K and 150K seeds/acre3.9 maturity, full seasonBob Wade, Jr., Back Forty Farms


Worth and Dee Ellis FarmsPhoto taken: August 4, 2006Full season planting3.9 maturity?Soybeans at R390K, 110K and 150K seeds/A

50 bu/a50 bu/a


Current Recommendation

• 15-inch rows, full season soybeans– 100,000 plants/acre final stand – Higher populations for DC soybeans

Response of Full-Season Soybean Crops to Narrow Rows, Kentucky

54

44

70

24

4340

66

18

0

10

20

30

40

50

60

70

80

1977 1978 1979 1980 1981 1982 1981-82 1983

Bu

/A 8" to 10"

16" to 19"

30" to 33"


40

*Data for each year has been averaged over varieties and/or locations. All plantings occurred before June 8.


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44

70

24

4340

66

18

50

45

64

26

44

40

20

0

10

20

30

40

50

60

70

80

1977 1978 1979 1980 1981 1982 1981-82 1983

Bu

/A 8" to 10"

16" to 19"

30" to 33"


41



54

44

70

24

4340

66

18

50

45

64

26

44

40

20

4144

54

23

41

36

54

22

0

10

20

30

40

50

60

70

80

1977 1978 1979 1980 1981 1982 1981-82 1983

Bu

/A 8" to 10"

16" to 19"

30" to 33"


42


Row spacing, Indiana2006

Row spacing (inches)

Yield (bu/ac)

7.5 70.2

15 70.5

30 65.6

LSD (0.05) 2.3


43Courtesy: Shawn Conley, Purdue University


44

(A) [1] Louisiana, 30, 20 v. 40, (9);[2] Kansas, 38 to 39.84, 8 v. 30, (12);[3] Illinois, 40.12, 7.5, 20 v. 31, (6);[4] Nebraska, 40.5, 10 v. 30, (17);[5] Nebraska, 40.5, 20 v. 30, (17);[6] Nebraska, 40.5, 10 v. 30, (17);[1] Nebraska, 40.5, 20 v. 30, (17);[8] Iowa, 42.09, 10, 20 v. 30, (36);

[9] Ontario, 42.3, 10 v. 30, (1);[10] Michigan, 42.7, 15 v. 30, (10);[11] Michigan, 42.7, 7.5 v. 30, (10);[12] Michigan, 42.7, 7.5 v. 30, (25);[13] Wisconsin, 43.3, 7.5, 15 v. 30, (29);[14] Wisconsin, 43.35, 8 v. 30, (28);[15] Wisconsin, 43.35, 8 v. 30, (28);[16] Minnesota, 44.2 to 45.58, 10 v. 30, (23).

Lee, C. D. 2006. Reducing row widths to increase yield: Why it does not always work. Online. Crop Management doi:10.1094/CM-2006-0227-04-RV.


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(B) [1] Arkansas, 35.69, 7.5 v. 38, (5);[2] Arkansas, 35.69, 7.5 v. 38, (5);[3] Louisiana, 30, 20 v. 40, (9);[4] Kansas, 39.77, 8 v. 30, (12);[5] Wisconsin, 43.35, 8 v. 30, (3).

Lee, C. D. 2006. Reducing row widths to increase yield: Why it does not always work. Online. Crop Management doi:10.1094/CM-2006-0227-04-RV.

Row Spacing 10 Environments (2004-2005)

Iowa

71.9 72.473.9 74.0

67.368.6 68.7

68.0

60.0

65.0

70.0

75.0

80.0

75 125 175 225

Seeding rate (X 1000)

Yie

ld (

Bu

/acr

e)

15 inch 30 inch

Chad Lee, Grain Crops Extension, © 2006 46

LSD 0.05 RS = 1.7 buLSD 0.05 RS X PPA = NS

©2003-2006. Palle Pedersen www.soybeanmanagement.info

Row Spacing Effect on Soybean Yield in Wisconsin (1997-1999)

6660

50

70

60

50

6354

45

0

10

20

30

40

50

60

70

80

Southern WI Central WI Northern WI

Yie

ld (

Bu

/acr

e)

7.5" 15" 30"


47(Bertram and Pedersen, 2004)©2003-2006. Palle Pedersen www.soybeanmanagement.info

Light Interception

• The crop must produce sufficient leaf area to intercept light completely as early as possible for maximum yields.


48

Ball et al. 2000b


49

Yield Cost of Delaying Weed Control in Soybean: Cost = 2-3% in soybean yield loss for every crop leaf stage of delay

0 9 14 19 24 28 32 3638 43 49 55

Timing of weed removal (Soybean growth stage or DAE)

0

5

10

15

20

25

30

35

40

45

50

So

yb

ea

n Y

ield

Lo

ss

(%

of

we

ed

fre

e)

V1 V2 V3

- 15" rows - 7.5" rows

- 30" rows

V4 V5 V6 V7 R1 R2 R3

5% yield loss line

Knezevic and Evans, 2000, University of Nebraska

©2003-2006. Palle Pedersen www.soybeanmanagement.info


50

Time of Removal in Soybean

Row spacing Weeds must be removed by (inches) soybean growth stage DAE

7.5” V3 19 days 15” V2 15 days 30” V1 9 days

V1 = 1st trifoliateV2 = 2nd trifoliate V3 = 3rd trifoliateV4 = 4th trifoliate

(Stevan Knezevic, UNL)©2003-2006. Palle Pedersen www.soybeanmanagement.info


Questions?

soybean. soybean growth stages vegetative stagesreproductive stages ve – emergencer1 – beginning...

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