Oakes
CORN POPULATION AND ROW WIDTH STUDY
W. Albus, L. Besemann
and H. Eslinger
Row width
studies in the Northern Cornbelt have demonstrated increasing yields as row
widths are narrowed, especially in high yield environments. There has also been interest in corn grown
in paired rows on 30-inch centers. The
paired rows reduce inter-row plant competition while allowing harvest with
30-inch row corn heads. This study was
initiated in 2006 to determine the response of corn grown in 15-inch, 30-inch
and paired rows 8-inches apart (10-inches apart in 2006) on 30-inch centers at
plant populations of 25,000, 30,000 and 35,000 plants/acre. Surprisingly in 2006, corn yield was not
increased in 15-inch rows or paired rows on 30-inch centers over corn grown in
single 30-inch rows. Corn yields in
2006 increased with increasing population from 230 bushles/acre at 25,000
plants/ac to 251 bu/acre at 35,000 plants/acre. This type of response to row width demonstrates the need to
continue testing modern hybrids, grown under current agronomics, for their
reaction to row spacing and population.
MATERIALS AND METHODS
|
Soil: |
Maddock sandy loam pH=7.5; 1.8% organic
matter; soil-P was very high, soil-K was medium and soil-S was low. |
|
Previous crop: |
2006 - soybean; 2005 - sweet corn; 2004 -
carrot, onion and sweetcorn. |
|
Seedbed Preparation: |
Flailed, disked and coulter chiseled in the fall; Coulter
chisel lightly once on April 26. Incorporate fertilizer and
smooth seed bed with a soil finisher on April 30. |
|
Planting: |
Planted on May 2 in 30-inch, 30-inch paired
(2 rows 8-inches apart on 30‑inch centers) and 15-inch row spacing. |
|
Plots: |
Plots were 17 ft long by 10 ft wide. Plots with 30-inch row spacing had
4 rows; 30-paired (30pr) had 4 paired rows; plots with 15-inch spacing
had 8 rows. Corn was planted at 30K,
37K and 44K per acre and thinned to 25K, 30K and 35K per acre on May 25. There were four reps. |
|
Fertilizer: |
November 2006, broadcast 9 lbs N/acre, 43 lbs P2O5/acre,
101 lbs K2O/acre and 13.5 lbs S/acre as 11-52-0, 0-0-60 and
90% elemental sulfur. Applied
200 lbs N/acre as 28-0-0 on April 30 and 100 lbs N/acre as urea on June 20. |
|
Irrigation: |
Overhead sprinkler irrigation as needed. |
|
Pest control: |
Applied Outlook (1 pt/acre on May 2),
Glyphosate Original (32 oz/acre) + AMS + (1 lb/10 gal) + NIS (0.5%v/v) on
June 5 and Cornerstone (32 oz/acre + AMS; (1 lb/10 gal) on June 19. |
|
Harvest: |
Hand harvested on October 23 and October
24. Harvest area was a ten foot by 5
foot section from each plot (two rows from the 30-inch row plots, two paired
rows from the 30-inched paired row plots and four rows from the 15-inch row
plots). |
Go to top of corn population and row width study
Dekalb DKC 47-10 and Pioneer 38H65
were planted in a split, split plot arrangement with hybrid as main plots, row
width as split plots and population as split, split plots. Row width had no significant effect on yield
or other parameters tested. This is the
second year of this study in which corn grown in 15-inch and paired rows on
30-inch centers yielded the same as corn grown in 30-inch single rows. This
is surprising and contrary to past data.
Corn grown in 20-inch rows had a 12 bu/acre yield advantage over corn in
30-inch rows at this same Site when studies from 1977-78 and 1980-82 are
averaged. Dekalb
DKC 47-10 and Pioneer 38H65 averaged 219 and 234 bu/acre. Increasing
plant population increased yield from 218
bu/acre at 25,000 plants/acre to 230 bu/acre at 30,000 and 35,000
plants/acre.
Hybrid had a
significant effect on test weight and there was a significant interaction
between hybrid and test weight. Test
weight in DKC 4710 declined 1.4 lb/bu as population increased from 25,000 to
35,000 whereas 38H65 declined 0.5 lb/bu.
Increasing population increased ear height from 37 inches at 25,000
plants/acre to 42 inches at 35,000.
By mid-August a
visible difference in the number of leaves senescing below the ear was noticed
among treatments. September 1, at the
R5.3 growth stage estimates were made of leaf firing below the ear. No leaf firing equaled a 0 score and all
leaves fired would equal a score of 9.
Pioneer 38H65 had a score of 4.5 compared to 5.8 for DKC 4710. Population had a very significant affect on
leaf firing (P=0.0001). Pioneer
38H65 and DCK 47-10 averaged 1.01 and 1.02 ears/plant. Increasing
populations decreased ears/plant from 1.04 at 25,000 plants/acre to 1.01 at
35,000 plants/acre.
This study will be continued with particular interest in the
effect of row width on yield. It was
somewhat baffling to find no response to narrow or paired rows in 2006 or
2007. It will be very interesting to
see if this is a fluke or if current hybrids grown with current agricultural
practices respond differently to row width than past data would indicate.
Table
1. Results of the field corn row width and population
study at the Oakes Irrigation Research Site in 2007.
Row width |
Yield |
Moisture |
Test wt. |
Ear height |
Leaf firing |
Stalk # |
Ear/plant |
|
bu/acre |
% |
lb/bu |
inches |
R5.3 |
1000s/A |
|
|
|
15 |
228.1 |
18.8 |
58.8 |
38 |
5.4 |
31.9 |
1.02 |
|
30 |
223.6 |
18.8 |
58.9 |
41 |
4.9 |
31.0 |
1.01 |
|
30pr |
226.7 |
18.8 |
58.9 |
39 |
5.2 |
31.2 |
1.02 |
|
C.V. % |
5.3 |
3.8 |
0.7 |
9 |
14.8 |
5.4 |
3.34 |
|
LSD (0.05) |
NS |
NS |
NS |
NS |
NS |
NS |
NS |
|
Go to top of the corn population row width study |
|||||||
Hybrid by row width
|
|
|
|
|
|
|
|
|
221.2 |
17.6 |
59.1 |
38 |
6.1 |
31.8 |
1.03 |
|
|
Pioneer 15 |
235.1 |
20.0 |
58.4 |
38 |
4.8 |
32.1 |
1.01 |
|
Dekalb 30 |
214.8 |
17.4 |
59.1 |
40 |
5.5 |
30.5 |
1.01 |
|
Pioneer 30 |
232.4 |
20.2 |
58.6 |
41 |
4.3 |
31.4 |
1.00 |
|
Dekalb 30pr |
219.7 |
17.6 |
59.4 |
38 |
5.9 |
31.5 |
1.02 |
|
Pioneer 30pr |
233.7 |
20.0 |
58.4 |
40 |
4.5 |
30.9 |
1.01 |
|
LSD (0.05) |
NS |
NS |
NS |
NS |
NS |
NS |
NS |
|
|
|
|
|
|
|
|
|
Hybrid by population
|
|
|
|
|
|
|
|
|
Dekalb 25K |
216.5 |
17.8 |
59.9 |
37 |
5.3 |
25.8 |
1.06 |
|
Pioneer 25K |
220.4 |
19.9 |
58.7 |
38 |
3.9 |
26.0 |
1.02 |
|
Dekalb 30K |
219.7 |
17.5 |
59.1 |
39 |
5.8 |
31.4 |
1.00 |
|
Pioneer 30K |
240.4 |
20.2 |
58.5 |
41 |
4.5 |
32.8 |
0.99 |
|
Dekalb 35K |
219.5 |
17.2 |
58.5 |
41 |
6.5 |
36.6 |
1.00 |
|
Pioneer 35K |
240.4 |
20.0 |
58.2 |
41 |
5.2 |
35.6 |
1.01 |
|
LSD (0.05) |
NS |
NS |
0.4 |
NS |
NS |
NS |
NS |
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