Oakes
W. Albus, L. Besemann and H. Eslinger
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
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. |
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.
Go to the top of the soybean row width & population study
|
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.
Go to the top of the soybean row width & population study
|
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.
Go to the top of the soybean row width & population study
|
|
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.
Go to the top of the soybean row width & population study
|
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.
Go to the top of the soybean row width & population study
|
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.
Go to the top of the soybean row width & population study
|
|
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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