Soybean Yield, Management and Physiology: Comparison

To Corn

North Central Branch, ASAMarch 16-17, 2005

Soybean Yield, Management and Physiology: Comparison

To Corn

North Central Branch, ASAMarch 16-17, 2005Emerson D. Nafziger

Crop SciencesUniversity of Illinois

Emerson D. NafzigerCrop Sciences

University of Illinois

Outline for TodayOutline for Today

• Current status of soybean yields

• Yield physiology

• Weather interactions

• Management issues

• Summary and “proposal”

• Current status of soybean yields

• Yield physiology

• Weather interactions

• Management issues

• Summary and “proposal”

Illinois Corn Yield

020406080

100120140160180200

1920 1940 1960 1980 2000

Year

Yie

ld, b

u/ac

re

Illinois Soybean Yields

0

10

20

30

40

50

60

1920 1940 1960 1980 2000Year

Yie

ld, b

u/ac

re

IL Corn:Soy Yield Ratio, 1920-2004

0.00.51.01.52.02.53.03.54.04.55.0

1920 1940 1960 1980 2000

Year

Rat

io,

bu

/ac:

bu

/ac

Yield Variability (CV) by IL CRD, 1990-04

0

5

10

15

20

25

NW NE W C E WSW ESE SW SE IL

Crop Reporting District

Yie

ld C

V, %

Corn

Soybean

Corn & Soy Acreage, NW MN

0

200

400

600

800

1000

1200

1400

Ac

res

, th

ou

sa

nd

s

Corn

Soybean

Yields, NW MN

0

20

40

60

80

100

120

140

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Bu

/acr

e

Corn

Soybean

C:S Yield Ratio, All MN

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

95 96 97 98 99 00 01 02 03 04

All MN

NW MN CRD

Corn and Soybean Acreage in Illinois, 1990-2004

6

7

8

9

10

11

12

1989 1991 1993 1995 1997 1999 2001 2003 2005

Year

Acre

s, m

illio

ns

Soybean

Corn

For Soybean Yield, How High is “High”?

For Soybean Yield, How High is “High”?

• R. Cooper (in IL and OH) reported over 100 bu in sub-irrigated semi-dwarf types• 300K seeds/acre in 7-in rows

• The reported world record (Ray Rawson) is 118 in MI

• 100+ bu/acre in county strip test in NW Illinois in 1990 on a “virgin” field

• Highest county average yield was 57 bu/acre in 1998 in JoDaviess County and in 2002 and 2004 in Carroll County, both in NW Illinois

• Highest yield in the UI variety trials was 82 bu/acre at Perry in 2004

• Highest Illinois state avg yield is 50.5 (2004)

• R. Cooper (in IL and OH) reported over 100 bu in sub-irrigated semi-dwarf types• 300K seeds/acre in 7-in rows

• The reported world record (Ray Rawson) is 118 in MI

• 100+ bu/acre in county strip test in NW Illinois in 1990 on a “virgin” field

• Highest county average yield was 57 bu/acre in 1998 in JoDaviess County and in 2002 and 2004 in Carroll County, both in NW Illinois

• Highest yield in the UI variety trials was 82 bu/acre at Perry in 2004

• Highest Illinois state avg yield is 50.5 (2004)

Why Not Higher Soybean Yields?Why Not Higher Soybean Yields?

• A partial list, compared to corn: • Soybean has ~50 percent higher energy

content per lb of seed and 7% heavier bushels than corn

• It does photorespiration, losing up to 1/3rd of photosynthesis to this “useless” process

• It fixes some of its own N• It fills rapidly for ~30 days v 45-50 for corn• More sensitive to air pollutants(?)

• A partial list, compared to corn: • Soybean has ~50 percent higher energy

content per lb of seed and 7% heavier bushels than corn

• It does photorespiration, losing up to 1/3rd of photosynthesis to this “useless” process

• It fixes some of its own N• It fills rapidly for ~30 days v 45-50 for corn• More sensitive to air pollutants(?)

0

1

2

3

4

5

6

7

3-Jun 23-Jun 13-Jul 2-Aug 22-Aug 11-Sep 1-Oct 21-Oct

Date

LA

I

A3244(97)-54 bu

W82(97)-42 bu

A3244(98)-61 bu

W82(98)-42 bu

Urbana and Monmouth, 1999

0

2000

4000

6000

8000

10000

12000

14000

3-Jun 3-Jul 2-Aug 1-Sep 1-Oct

lb p

er a

cre

W82-plant

A 3244-plant

W82-seed

A 3244-seed

Yield v maturity date, Reg. 3, MG 3 RR, 2004Yield v maturity date, Reg. 3, MG 3 RR, 2004

40

45

50

55

60

65

70

75

80

9/5 9/10 9/15 9/20 9/25

Date of maturity

Yie

ld,

bu

/ac

Yield v maturity date, Reg. 3, RR, 2000Yield v maturity date, Reg. 3, RR, 2000

40

45

50

55

60

65

9/1 9/6 9/11 9/16 9/21 9/26 10/1

Maturity date

Yie

ld

Soybean Yield PhysiologySoybean Yield Physiology

• The ability to maintain high photosynthetic rates throughout seed filling stages defines high yield potential

• Among C3 crops, soybean has relatively high photosynthetic capacity

• The maximum sustained seed fill rate is ~3 bushels per day

• This fill rate sustains for ~30 days under normal temps; can be longer if cooler

• By far the largest reason for decreased Ps causing lower seed fill and yield is inadequate water

• The ability to maintain high photosynthetic rates throughout seed filling stages defines high yield potential

• Among C3 crops, soybean has relatively high photosynthetic capacity

• The maximum sustained seed fill rate is ~3 bushels per day

• This fill rate sustains for ~30 days under normal temps; can be longer if cooler

• By far the largest reason for decreased Ps causing lower seed fill and yield is inadequate water

A Mystery of Soybean Yield Physiology

A Mystery of Soybean Yield Physiology

• There is no clear indication whether soybean is “source-limited” (inadequate Ps) or “sink-limited” (not enough places to accept Ps products = sugars)

• This “confusion” may be of minimal importance as long as breeders can maintain progress, but it’s still of interest in the field

• There is no clear indication whether soybean is “source-limited” (inadequate Ps) or “sink-limited” (not enough places to accept Ps products = sugars)

• This “confusion” may be of minimal importance as long as breeders can maintain progress, but it’s still of interest in the field

Evidence for Source LimitationEvidence for Source Limitation

• Increasing CO2 in the atmosphere increases yields (SoyFACE & others)

• Ozone & other pollutants reduce yield

• Defoliation reduces yield, if it’s severe enough

• Drought reduces yield, often by reducing seed size

• Increasing CO2 in the atmosphere increases yields (SoyFACE & others)

• Ozone & other pollutants reduce yield

• Defoliation reduces yield, if it’s severe enough

• Drought reduces yield, often by reducing seed size

Evidence for Sink LimitationEvidence for Sink Limitation

• Removing some leaves increases Ps rate in remaining leaves

• Pale green (low chlorophyll) mutants yield more than Ps rates would suggest

• Leaves accumulate starch during the day; inability to utilize sugar fast enough?

• Adding N fertilizer (low fixation) fails to increase yields

• Removing some leaves increases Ps rate in remaining leaves

• Pale green (low chlorophyll) mutants yield more than Ps rates would suggest

• Leaves accumulate starch during the day; inability to utilize sugar fast enough?

• Adding N fertilizer (low fixation) fails to increase yields

“Practical” Yield Physiology“Practical” Yield Physiology

• With exceptions, soybean plants initiate enough seeds for high yields, but may fail to adequately sustain pods or fill seeds due to reduced Ps during critical stages (R5-R6)

• Canopies and leaves are usually adequate, but root systems often fail to provide enough water to maintain Ps

• With potential seedfilling rates of 3 bu/day, reductions in Ps for even short stretches in August hurt yields

• Starting to fill seeds slightly earlier or extending seedfilling slightly longer can increase yields greatly

• With exceptions, soybean plants initiate enough seeds for high yields, but may fail to adequately sustain pods or fill seeds due to reduced Ps during critical stages (R5-R6)

• Canopies and leaves are usually adequate, but root systems often fail to provide enough water to maintain Ps

• With potential seedfilling rates of 3 bu/day, reductions in Ps for even short stretches in August hurt yields

• Starting to fill seeds slightly earlier or extending seedfilling slightly longer can increase yields greatly

Days after flowering0 10 20 30 40 50 60 70

R1R2 R3 R4 R5 R6 R7 R8

Seed Filling

Pod Development

Flowering

Vegetative Growth

Soybean Reproductive Development

Indeterminate Growth

©Palle Pedersen

Seed and Pod DevelopmentSeed and Pod Development

©Palle Pedersen

R5 R6R8 (all)

R7 (1)

Freeport, Illinois

0

10

20

30

40

50

60

70

80

90

100

Ave

rag

e h

igh

tem

per

atu

re, F

2003

2004

Freeport, Illinois

0

10

20

30

40

50

60

70

Av

era

ge

low

te

mp

era

ture

, F

2003

2004

Freeport, NW Illinois

0

1

2

3

4

5

6

Ra

infa

ll, in

ch

es

2003 2004

Soybean management goals:Soybean management goals:

• To enable to crop to take full advantage of good weather when it happens

• To protect the yield of the crop, at least partly, from disastrously low yields when the weather is poor

• In practical terms, we need to “position” the crop for maximum seedfilling rates

• To enable to crop to take full advantage of good weather when it happens

• To protect the yield of the crop, at least partly, from disastrously low yields when the weather is poor

• In practical terms, we need to “position” the crop for maximum seedfilling rates

Planted Apr. 5Photo May 24

Planting Date & Rateave. 9 No. IL sites, 2001-03, mid-maturity, 4 seeding

rates

Planting Date & Rateave. 9 No. IL sites, 2001-03, mid-maturity, 4 seeding

rates

42.4

47.9 47.9

45.8

40

42

44

46

48

50

Early Apr Late Apr Early May Late May

Planting Date

Ave

. Yie

ld, b

pa

Effect of Planting Date on Maturity and Plant Height

(response to day length)

Effect of Planting Date on Maturity and Plant Height

(response to day length)

Planting Date

Maturity Date

Plant Height-in.

April 11 Sept. 16 28.9

April 24 Sept. 17 30.5

May 11 Sept. 22 31.6

May 29 Sept. 28 33.2

Monmouth

Planting Date and Seeding Rate

Data from J. Gander, Pioneer Hi-BredData from J. Gander, Pioneer Hi-Bred

E. Central Illinois, 4 yr

0

10

20

30

40

50

60

50 100 150 200 250

Seeding rate, 000/acre

Yie

ld, b

u/a

cre

Mid-Apr

E. May

Mid-May

E. June

Planting Date and Seeding Rate

University of IllinoisUniversity of Illinois

0

10

20

30

40

50

60

50 100 150 200 250

Seeding rate, 000/acre

Yie

ld, b

u/a

cre

6-Apr

24-Apr

9-May

26-May

Planting Rate and Variety

Data from J. Gander, Pioneer Hi-BredData from J. Gander, Pioneer Hi-Bred

East Central Illinois

30

35

40

45

50

55

50 100 150 200 250

Seeding rate, 000/acre

Yie

ld, b

u/a

cre

92B74

92B84

93B01

93B26

93B36

93B47

Seeding Rate and Row Spacing

E. Adee, University of IllinoisE. Adee, University of Illinois

Avg of 14 Site-Years, N. IL

30

35

40

45

50

55

60

100 125 150 175 200 225 250

Seeding rate, 000/acre

Yie

ld, b

u/a

cre

Drill

15-inch

30-inch

Seeding Rate and Row Spacing

P. Pedersen, Iowa State Univ.P. Pedersen, Iowa State Univ.

Iowa, 3 site-years, 2004

0

10

20

30

40

50

60

70

80

50 100 150 200 250

Seeding rate, 000s/acre

Yie

ld, b

u/a

cre

15-inch

30-inch

Seeding Rate Economics

University of IllinoisUniversity of Illinois

$15.00/125K unit; $5.00 per bu soybean

30

35

40

45

50

50 100 150 200 250

Seeding rate, 000/acre

Yie

ld,

bu

/acr

e

↑ Optimum

Variety Maturity & Planting Date, 2001-03

Avg. of 9 N. Ilinois Trials

0

10

20

30

40

50

60

Early Apr Late Apr Early May Late May

Planting date

Yie

ld,

bu

/ac

re

Early

Mid

Late

Inoculants on Soybean, 2004

56

58

60

62

64

66

68

70

North Central South Average

Illinois locations (2 per region)

Yie

ld,

bu

/acr

e

Untreated

Optimize

Launcher

Prosurge

Lactofen on Soybean, Urbana, 2004

40

45

50

55

60

65

70

Control Cobra Phoenix

Yie

ld, b

u/a

cre

Planting ManagementPlanting Management

• 100,000 plants per acre is enough to maximize yield, if they’re all healthy and evenly distributed

• Variety, varietal maturity, row spacing, and planting date don’t seem to affect seeding rate/plant population response much

• Good quality soybean seed responds little if any to seed fungicidal seed treatment or inoculant

• Planting in the first half of May is appropriate for soybean, with little loss 1-2 weeks on either side of that period

• 100,000 plants per acre is enough to maximize yield, if they’re all healthy and evenly distributed

• Variety, varietal maturity, row spacing, and planting date don’t seem to affect seeding rate/plant population response much

• Good quality soybean seed responds little if any to seed fungicidal seed treatment or inoculant

• Planting in the first half of May is appropriate for soybean, with little loss 1-2 weeks on either side of that period

Monmouth Rotation, 2002-04

0

10

20

30

40

50

60

70

WCS CWS SSS CS

Rotation

So

ybea

n y

ield

Tilled

No-till

Monmouth CCS Soybean, 2004

56

58

60

62

64

66

68

70

72

CCS CS

Rotation

Yie

ld, b

u/a

cre

93B67 HY

93B47 DEF

6 Illinois Soybean Sites, 2000-03

44

45

46

47

48

No-Till Chisel Deep Rip

Yie

ld, b

u/a

cre

Spr NT

Spr Till

According to Some…According to Some…

High corn yields are an accomplishment

While

High soybean yields are an accident

High corn yields are an accomplishment

While

High soybean yields are an accident

Now We Know Better!Now We Know Better!

• Still, it’s clear that managing soybean within our weather and soils will disappoint sometimes

• But, the US remains a good place to grow soybeans, and with continued attention to genetics and inputs, we can continue to compete

• Still, it’s clear that managing soybean within our weather and soils will disappoint sometimes

• But, the US remains a good place to grow soybeans, and with continued attention to genetics and inputs, we can continue to compete

Seedfill Monitoring in SoybeanSeedfill Monitoring in Soybean

• As a pilot in 2005, we are going to take weekly samples of soybean pods from 25-30 plants

• Dry and thresh to determine seed wt per plant

• Relate ΔDW to temperature, moisture, and solar radiation during past week

• Care to join us? ednaf@uiuc.edu

• As a pilot in 2005, we are going to take weekly samples of soybean pods from 25-30 plants

• Dry and thresh to determine seed wt per plant

• Relate ΔDW to temperature, moisture, and solar radiation during past week

• Care to join us? ednaf@uiuc.edu

Thank YouThank You