Ohio State University Extension Bulletin

Agronomic Crops Team On-Farm Research Projects 2000

Special Circular 179-01


Placement of P and K on Corn

Jeff McCutcheon, Extension, Agriculture/Natural Resources, Agent
Phil Rzewnicki, On-Farm Research Coordinator

Objective

To compare corn yields under three different fertilizer programs.

Background


Cooperator: Keith Dennis Soil Test: pH 6.5, P 23 ppm,
County: Perry   K 114 ppm, CEC 9 meq/100g
Nearest Town: Rushville Variety: Seed Consultants 1118
Major Soil Types: Centerburg & Luray Row Width: 36 inches
  silt loams Planting Rate: 27,000/A
Drainage: Tiled Planting Date: May 11, 2000
Tillage: Minimum Till Harvest Date: November 28, 2000
Previous Crop: Corn  


Methods

A study was designed to compare corn yield under three different phosphorus and potassium fertilizer programs. Plots were field length (>750 ft.) and 54 ft. wide, replicated six times and completely randomized. Application of 190 lbs. per acre actual nitrogen was applied as anhydrous to all three plots. One fertilizer program was 18-46-60 actual applied by broadcasting before tillage. The second fertilizer program was 18-46-60 actual applied with the anhydrous and placed about eight inches in the soil profile. The applicator was a DMI Ecoltill 2500 with shark-fin points fed by a Harmonšs 3100 air system. The third program was 9-23-30 actual applied with the anhydrous and placed at the same depth as the second program. All fertilizer applications, including anhydrous, were made on April 27 or 14 days before planting.

All plots received a surface tillage pass with an Aerway unit. The shallow tillage probably incorporated the broadcasted fertilizer to a depth of two to three inches. This is the third year for this trial using the same treatment areas as the previous years.

Results


Treatment Average
Yield Bu/A1
Treatment
Cost/A2

Broadcast Full Rate 161.98 $19.04
Full Rate Deep Placement 166.12 $24.40
Half Rate Deep Placement 160.18 $16.15

F<1 NS3  

1 15% moisture.
2 Includes actual fertilizer cost, plus estimated machinery and fuel cost based on "Ohio Farm Machinery Economic Cost Estimates for 2000."
3 NS = Not Significant at P = 0.05, CV = 4.6%.

Summary

Finding no significant differences between the three treatments was not surprising since the soil-test values are above the critical level for both phosphorus and potassium. Past research indicates that if soil-test values are above the critical level, then specific placement of the fertilizer will have no significant effect on yield. This trial should also be done on a field that has soil-test values below the critical level. In that case, past research indicates that fertilizer placement will have a greater effect on yield.

For more information, contact:

Jeff McCutcheon
Ohio State University Extension, Perry County
104 S. Columbus St., P.O. Box 279
Somerset, OH 43783
740-743-1602
mccutcheon.30@osu.edu


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