Potassium Fertilizer Timing in Corn

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Experiment Info


Planted 5/7/2013
Variety: DKC53-78
Population: 31,500
Row Spacing: 30
Previous Crop: Corn
Plot Size: 15’ x 265’
Replications: 4
Potash 11/9/12
PRE 5/8
Sidedress: 6/8
Harvested: 10/15/13


Soil Test Values (ppm)

 pH 6.9
CEC 9.5
%OM 2.1
Bicarb P 10
K 112
S 7
%K 3.0
%Mg 19.5
%Ca 77.2
%H 0
Zn 1.5
Mn 10
B 0.5
Yield Goal: 175 bu
Target Fertilizer Rate: 192-90-48

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To determine the optimum time for fertilizing a corn crop with potassium.

Agro-Culture Liquid Fertilizer’s Sure-K is seed safe to allow application of the required nutrients in-furrow when planting. Sometimes the question of when to apply potassium, if not with the planter, comes up. In determining to answer that question, a broadcast rate of Sure-K was applied in the fall. A comparison of fall broadcasted Potash was also applied. Both treatments were incorporated into the soil by chisel plowing the previous corn crop residue. The spring broadcast treatment of Sure-K was made and incorporated with a soil finisher before planting. Yield results appear in the table below.

potassium fertilizer timing on corn


  • The 4 gal/A rate of Sure-K gave nearly identical yields as the higher rate of Sure-K broadcasted or the dry Potash applications. The in-furrow placement puts nutrients where they are needed.
  • Planter applied, fall or spring broadcast of potassium had no significant yield advantage to each other. The difference comes in the amount of nutrients applied to realize similar yields.
  • In spite of these results, broadcast applications are not recommended at this time until more research is conducted.
  • The no planter fertilizer treatment lacked the necessary nutrients needed to accomplish its yield potential.
  • If Sure-K is going to be broadcast applied, a 20% increase in rate is needed to achieve comparable yields to planter applied rates.