Ed Lentz, Extension District Specialist, Agronomy
John Smith, Extension Agent, Agriculture and Natural Resources
Anne Dorrance, Extension State Specialist, Plant Pathology
To evaluate the effect of seeding rate on white mold development in soybeans.
| Cooperator: | Jim Becher | Soil test: | Unavailable |
| County: | Auglaize | Fertilizer: | None |
| Nearest Town: | Wapakoneta | Planting Date: | June 4, 2002 |
| Drainage: | Naturally well-drained | Planting Rate: | See treatments |
| Soil type: | Blount and Pewamo | Row Width: | 7.5-inch |
| silt loam | Herbicides: | Roundup Ultra | |
| Tillage: | No till | 1 qt/A + AMS | |
| Previous Crop: | Corn | Harvest Date: | October 8, 2002 |
| Variety: | Asgrow AG3302 |
Experimental design was a randomized complete block with three treatments replicated five times. Treatments were three seeding rates: 110,000; 165,000; and 220,000 seeds/A. A John Deere 750 Drill was used at planting. Plots were 30 feet wide and 400 feet long. The center of each plot (20 feet wide) was harvested for grain yield. Grain weight was estimated by a weigh wagon. A Dickey John tester was used for grain moisture. Yield was adjusted to 13% moisture. Harvest population was estimated by counting plants from four adjacent rows for 50 feet.
Even though the field has a history of white mold, environmental conditions were not conducive for disease development. Thus, the results only discuss the relationship between grain yield and seeding rate.
Table 1. Soybean Grain, Harvest Moisture, and Population Response to Seeding Rate.a
| Seeding | Grain | Harvest | Harvest |
| Rate | Yield | Moisture | Population |
| (seeds/A) | (bu/A) | (%) | (plants/A) |
| 165,000 | 42.8 a | 11.4 a | 141,622 b |
| 220,000 | 42.4 a | 11.2 b | 169,431 a |
| 110,000 | 39.8 b | 11.2 b | 80,359 c |
| LSD (0.05) | 2.0 | 0.2 | 18,898 |
| F-test | 6.9 | 3.3 | 62 |
| a Means followed by the same letter within a column are not significantly different. | |||
The yield for the lowest seeding rate was statistically less than the other two treatments. However, the harvest population for the lowest seeding rate was 73% of the target population, whereas the other treatments were approximately 85%. The lack of stand establishment would affect the lowest seeding rate more than other treatments.
The results of this study would suggest that a grower might be able to reduce production costs by reducing seeding rate. Approximately $7/A may be saved by reducing seeding rate 50,000 seeds/A, assuming a 50 lb bag of Roundup Ready Soybeans cost $20, and 3,000 seeds/lb. Estimating cash market price of $5.50 per bushel, the 165,000 seeds/A rate would have resulted in 9 to 10 dollars per acre more profit than the other two seeding rates. Further studies are needed to determine if lower seeding rates might be used for years with larger yields.
For more information, contact:
Ed Lentz
OSU Extension
Northwest District
1219 W. Main Cross St., Suite 202
Findlay, OH 45840
419-422-6106
lentz.38@osu.edu
John Smith
OSU Extension
Auglaize Couny
208 S. Blackhoof St.
Wapakoneta, OH 45895
419-738-2219
smith.132@osu.edu
Anne Dorrance
Plant Pathology
OARDC
1680 Madison Ave.
Wooster, OH 44691
330-202-3560
dorrance.1@osu.edu