Ohio State University Extension Bulletin

Agronomic Crops Team On–Farm Research Projects 2000

Special Circular 179–01

Effect of Planter Unit Repair and Calibration
on Yields of Corn

Steve D. Ruhl, Extension Agriculture and Natural Resources Agent

Objective

To evaluate the effect of calibration and repair of planter units on yields of corn.

Background

Site I
Cooperator: Tom Weiler
County: Morrow
Nearest town: Chesterville
Soil Type: Sloan silty clay loam
Drainage: Systematic
Tillage: Conventional
Previous Crop: Soybeans
Variety: Golden Hrvest 2495
Soil test: pH = 7.0, P = 23 ppm
K = 154 ppm
Fertilizer: 206-70-99 actual N-P-K lbs./A
Planting Date: May 1, 2000
Planting Rate: 30,100 seeds/A
Harvest Date: October 23, 2000
Herbicides: PRE ­ Dual II Magnum (1 qt./A),
Atrazine (1.5 lb./A),
Balance (1.0 oz./A)
POST ­ Clarity (1 pt./A)
Row width: 30 inch
Site II
Cooperator: Steve Ruhl
County: Morrow
Nearest town: Williamsport
Soil Type: Sleeth silty clay loam
Drainage: Systematic
Tillage: Conventional
Previous Crop: Soybeans
Variety: Golden Harvest 2515
Soil test: pH = 6.5, P = 56 ppm
K = 162 ppm
Fertilizer: 167-69-30 actual N-P-K lbs./A
Planting Date: April 29, 2000
Planting Rate: 30,100 seeds/A
Harvest Date: October 31, 2000
Herbicides: PRE ­ Bicep II Magnum (1 qt./A),
Balance (1.5 oz./A)
POST ­ Clarity (0.5 pt./A)
Row width: 30 inch

Methods

Three seeding units were removed from a John Deere 7000 six-row planter. These units were calibrated and any needed repairs and adjustments were made. The calibrated units were compared to the non-calibrated units in a split-planter study. The study was replicated at two sites. The treatments were replicated four times at each site, and the entire six rows were harvested and measured using a weigh wagon. The lengths of the plots ranged from 715 to 766 feet. The speed of planting was 5 mph. The harvest population was not counted at the Chesterville site.

Results

Treatments Site I
Corn Yield
(bu/A)		 Site II
CornYield
(bu/A)		 Site II
Population
(plants/A)
Calibrated, repaired adjusted units 158.1 a 181.8 a 28,000
Other units 146.0 b 174.8 b 26,250
LSD (0.05) 5.2 6.0 NS
F 54.8 13.9 4.2
CV (%) 1.5 1.5 4.5

Summary

The results of this study did show that the calibration and repair and adjustment of the planting units of the J.D. 7000 planter did affect yields. The calibrated, repaired units out yielded the other units by 12 and 7 bushels per acre at the two sites. Population counts at the Williamsport site were not statistically different. There were probably not enough replicates to differentiate a 5 to 6 percent difference in the stand counts.

It appears that calibration and repair of planter units can make a significant difference in corn yields. Producers should periodically calibrate, repair, and adjust seed-planting units.

Acknowledgment

The author and collaborating farmer would like to thank Pioneer Hybrids for calibrating and repairing the three units so the study could be completed. Also, thanks are extended to Royster Clark for weighing the plot at the Williamsport location.

For additional information, contact:

Steve Ruhl
Ohio State University Extension, Morrow County
871 W. Marion Rd., Suite 102
Mt. Gilead, OH 43338
419-947-1070
ruhl.1@osu.edu

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