Oakes Irrigation Research Site
Carrington Research Extension CenterNorth Dakota State University
P.O. Box 531, Oakes, ND 58474-0531, Voice: (701) 742-2744, FAX: (701) 742-2700, E-mail: Walter.Albus@ndsu.edu

SOYBEAN ROW WIDTH & POPULATION STUDY

W. Albus, L. Besemann and H. Eslinger

 

Results summary

Table 31.  Results of the soybean row spacing by plant population at the Oakes Irrigation Research Site in 2006.

                 Variety

                 Row spacing

                 Population

                 Variety by row width

                 Variety   by   population

                 Row width by population

                 Variety by row width by population

                

INTRODUCTION

                                                                      

           From 1984-87 Walter Albus found irrigated soybeans at plant populations of 100,000, 150,000 and 200,000 averaged 52, 53 and 55 bu/acre respectively and 56 and 50 bu/acre in 15 and 30-inch rows respectively, at the Oakes Irrigation Research Site.  With the introduction of roundup ready soybeans (RR) the effect of row width and population needs to be revisited.  Increasing early soybean canopy through narrow rows and higher populations for weed control is less of an issue with RR beans.  The increased cost associated with RR beans forces a more conservative approach to planting rates.  Also increasing pressure from Sclerotinia (white mold) has producers looking to 30-inch rows to provide better air-flow for foilage to dry.  Richard Greenland initiated a row, population study in soybeans in 2005 to address these issues.  Results from 2005 showed no significant impact of either row width (10, 20 and 30-inch) or plant population (73,000, 108,000 and 143,000 plants/acre) on soybean yield.  Two soybean varieties, were grown at three row widths; 10, 20 and 30-inch rows and at three populations; 100,000, 150,000 and 200,000 plants/acre in 2006

 

MATERIALS AND METHODS

 

 

Soil:

Embden sandy loam, Helca sandy loam and Maddock sandy loam; pH=5.9; 2.3% organic matter; soil-P and soil-K was very high; soil-S were medium.

Previous crop:

2005 - sweet corn; 2004 - pumpkin and soybean; 2003 - field corn.

Seedbed preparation:

Fall disk.  Multiweed (field cultivate) three times; once on May 4 to incorporate fertilizer and twice on May 9 to smooth the seedbed and to incorporate herbicide.

Planting:

Planted on May 12 in 10, 20 and 30-inch rows.  All beans were inoculated just prior to planting.

Plots:

Plots were 17 ft long by 10 ft.  Plots in 10-inch rows had 10 rows per plot, 20-inch row plots had 5 rows per plot and 30-inch row plots had 4 rows per plot.  Two varieties were planted in each row width at 100K, 150K and 200K plant populations per acre.  There were four reps.

Fertilizer:

On April 10, broadcast 20 lbs N/acre, 45 lbs P2O5/acre, 51 lbs K2O/acre and 13 lbs S/acre as 21-0-0-24, 11-52-0 and 0-0-60.

Irrigation:

Underground drip irrigation as needed.

Pest control:

Treflan (1 pt/acre on May 9), Glyphosate Original + NIS + AMS (1qt/acre + 0.05%v/v + 1 lb/10gal on June 1 and June 18) for weed control and Warrior (3 oz/acre on August 24) for control of soybean aphids.

Harvest:

Harvested on October 2 with a Hege plot combine.  Harvest area: the center two rows in the plots with 30-inch row spacing, the center three rows in plots with 20-inch row spacing and the middle 8 rows in plots with 10-inch row spacing.  All plots harvested were 17 feet in length.

 

RESULTS

 

           Croplan 995 and Asgrow 801 were planted in a split, split plot arrangement, variety as main plots, row width as split plots and population as split, split plots.  Harvest populations of 110,400 163,600 and 203,900 were close to the target populations of 100,000, 150,000 and 200,000 plants/acre.  Croplan 995 and Asgrow 801 averaged 63 and 56 bu/ac, respectively.  Row width and plant population had no significant effect on yield.  Lodging increased from a score of 2.7 in 10-inch rows to 4.7 in 30-inch rows.  Lodging increased from 3.0 at 100,000 plants/acre compared to 4.5 at 200,000 plants/acre.  There was an interaction between variety and row width.  Lodging was higher in 801 than in 995 at low populations, but lower at high populations.  There also was an interaction among variety, row width and population.  Lodging in 801 increased more than 995 with increasing populations in 10-inch wide rows.  Conversely lodging in 995 increased more than 801 with increasing populations in 30-inch wide row.  These studies will be continued to collect data in a multiple of environments. 

 

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Table 31.  Results of the soybean row spacing by plant population at the Oakes Irrigation Research Site in 2006.

 

Yield

Test wt.

Lodging1

population

Variety

bu/acre

lb/bu

 

1000s/A

Asgrow 801

56.3

57.8

3.6

145.5

Croplan 995

62.9

58.3

3.8

173.2

 

 

 

 

 

LSD (0.05)

6.0

0.3

NS

13.9

C.V. (%)

13.4

0.6

46.5

1.8

1Lodging: ) is no lodging; 9 is flat.

 

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Yield

Test wt.

Lodging1

population

Row spacing

bu/acre

lb/bu

 

1000s/A

10

60.5

58.3

2.7

149.7

20

60.9

57.8

3.6

168.2

30

59.3

58.0

4.7

160.0

 

 

 

 

 

LSD (0.05)

NS

0.4

1.0

7.9

C.V. (%)

9.9

0.9

37.0

2.4

1Lodging: ) is no lodging; 9 is flat.

 

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Yield

Test wt.

Lodging1

population

Population

bu/acre

lb/bu

 

1000s/A

100K

59.4

58.2

3.0

110.4

150K

59.3

57.9

3.5

163.6

200K

59.9

58.1

4.5

203.9

 

 

 

 

 

LSD (0.05)

NS

NS

0.8

6.8

C.V. (%)

8.2

0.9

35.5

0.8

1Lodging: ) is no lodging; 9 is flat.

 

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Yield

Test wt.

Lodging1

population

Variety by row width

bu/acre

lb/bu

 

1000s/A

Asgrow 801

10

56.4

58.0

3.3

134.2

Croplan 995

10

63.2

58.6

2.1

165.2

Asgrow 801

20

57.1

57.6

3.5

152.5

Croplan 995

20

63.3

58.1

3.8

184.0

Asgrow 801

30

55.2

57.8

4.0

149.9

Croplan 995

30

62.1

58.2

5.4

170.2

 

 

 

 

 

 

LSD (0.05)

NS

NS

1.4

NS

1Lodging: ) is no lodging; 9 is flat.

 

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Yield

Test wt.

Lodging1

population

Variety   by   population

bu/acre

lb/bu

 

1000s/A

Asgrow 801

100K

55.2

58.0

3.3

100.1

Croplan 995

100K

63.6

58.4

2.7

120.8

Asgrow 801

150K

56.1

57.5

3.3

152.0

Croplan 995

150K

62.6

58.3

3.8

175.2

Asgrow 801

200K

57.4

57.9

4.3

184.4

Croplan 995

200K

62.4

58.2

4.8

223.5

 

 

 

 

 

 

LSD (0.05)

NS

NS

NS

9.6

1Lodging: ) is no lodging; 9 is flat.

 

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Yield

Test wt.

Lodging1

population

Row width by population

bu/acre

lb/bu

 

1000s/A

10

100K

61.2

58.5

2.3

102.8

20

100K

59.8

58.0

2.8

113.1

30

100K

57.2

58.2

3.9

115.4

10

150K

61.6

58.1

2.5

149.6

20

150K

58.2

57.6

3.1

168.1

30

150K

58.3

58.1

5.0

173.0

10

200K

56.6

58.4

3.4

196.6

20

200K

62.6

58.0

5.0

223.6

30

200K

60.5

57.8

5.3

191.7

 

 

 

 

 

 

LSD (0.05)

NS

NS

NS

11.7

1Lodging: ) is no lodging; 9 is flat.

 

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Yield

Test wt.

Lodging1

population

 Variety by row width by pop

bu/acre

lb/bu

 

1000s/A

Asgrow 801

10

100K

53.6

58.1

2.3

  91.2

Croplan 995

10

100K

68.9

58.8

2.3

114.5

Asgrow 801

20

100K

57.8

57.8

3.8

103.9

Croplan 995

20

100K

61.8

58.2

1.8

122.2

Asgrow 801

30

100K

54.2

58.2

3.8

105.2

Croplan 995

30

100K

60.2

58.2

4.0

125.7

Asgrow 801

10

150K

59.0

57.8

2.8

136.3

Croplan 995

10

150K

64.1

58.4

2.3

163.0

Asgrow 801

20

150K

54.6

57.3

3.0

157.6

Croplan 995

20

150K

61.8

57.9

3.3

178.7

Asgrow 801

30

150K

54.8

57.6

4.0

162.1

Croplan 995

30

150K

61.7

58.6

6.0

184.0

Asgrow 801

10

200K

56.7

58.2

5.0

174.9

Croplan 995

10

200K

56.5

58.6

1.8

218.3

Asgrow 801

20

200K

58.8

57.8

3.8

196.0

Croplan 995

20

200K

66.4

58.2

6.3

251.1

Asgrow 801

30

200K

56.7

57.8

4.3

182.3

Croplan 995

30

200K

64.3

57.9

6.3

201.0

 

 

 

 

 

 

 

LSD (0.05)

NS

NS

1.9

NS

1Lodging: ) is no lodging; 9 is flat.

 

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