As we prepare for the 2015 corn crop, we’ve been busy making decisions on acres to be planted, maturities, hybrids and planting populations. One of the most impactful things we can do to increase yields is develop a fertility strategy.

To begin developing a fertility strategy, start with an analysis of your soil data derived from taking soil samples. The information we need to pay attention to is nutritional indexes, pH and CEC. From that information, we can determine how much of each nutrient we need to provide to our crop to reach our yield goals. For example, a 200 bu/acre corn yield will require 225 lbs of potassium, 125 lbs of phosphorus, 38 lbs of magnesium, 35 lbs of sulfur, 2.15 lbs of iron, 1.25 lbs of manganese and 0.9 lbs of zinc as well as other micronutrients. If any of these nutrients are limited, you will not reach your yield goal. We don’t necessarily need to apply those amounts, but we must make sure those amounts are available. No amount of fungicide, herbicide, insecticide, or water can overcome a nutrient deficiency.

Timely application of materials is critical for the success of your fertility strategy. Lime needs to be applied at the right time, allowing for the time it takes to dissolve and work through the soil profile. Tillage and soil moisture are factors that can affect reaction time. Dry fertilizer applications will also take time to move into the soil solution and become available for plants.


Soil pH can greatly affect nutrient availability. Many growers are challenged with multiple soil types in the same field. GPS sampling by soil zone is one tool that can help us reach our optimum pH for our crop mix. Another practice that has proven to be beneficial is supplemental foliar feeding. We can apply nutrients in small amounts foliarly that will help us overcome any nutrient “tie up” we may have in the soil. We must be careful in selecting foliar nutritional products in that some may be higher in salts and could result in crop damage. Coastal’s Quantum for Corn is a low salt foliar fertilizer containing steady release nitrogen, manganese, iron, and zinc. This product can be mixed with fungicides, herbicides and insecticides.

At planting, starter fertilizer applications are beneficial in that nutrients are supplied into or close to the root zone which help to ensure a uniform emergence and stand.

2 x 2 vs. In-Furrow Application

There are two ways to apply starter fertilizer. The first is 2×2, meaning 2 inches beside the seed and 2 inches in the ground. Application is made with a nozzle just above soil level, spraying in a trench that is usually made with a coulter. The material used in this application is typically a polyphosphate fertilizer (11-37-0) and is sometimes mixed with liquid nitrogen. Since polyphosphate fertilizers are high in salt, care must be taken to not get too close to the seed as crop damage can occur.

The advantage of a 2×2 application is that we can use significant amounts of nitrogen and phosphorus relatively near the root zone.

The main disadvantage of 2×2 is nutrient availability. Polyphosphates can take time to become available to the plant. They have to break down to orthophosphates before the plant can use them. It can also take time for the roots to grow into the fertilizer. In addition, equipment for this application can be cumbersome and costly.

The other way to apply starter fertilizer is in-furrow using orthophosphate fertilizer. There are different analysis available, and they are low in salt which makes them seed safe. One of the most popular ways to apply orthophosphates is with Keeton® Seed Firmers, which place the solution throughout the seed furrow.

The advantages of in-furrow orthophosphates include:

  • Nutrients are available to the seed immediately
  • Orthos are a complete fertilizer including potassium (e.g., 9-18-9 or 6-24-6 vs. 11-37-0)
  • In-furrow gives you the option of using insecticides and fungicides
  • Low volumes (typical rate 3-5 gal)
  • Every drop contains the same amount of fertilizer
  • Can be used at planting on soybeans as well

The disadvantage of in-furrow is that less actual pounds of nutrients per acre are available.

In either the 2×2 or in-furrow application, micronutrients may be added.

Also with either application, Advance LCO may be added to aid in nutrient availability, solubility and to stimulate root growth. For customers using Advance LCO, Coastal offers an equipment rebate program.

Contact your Coastal representative to get started on your corn fertility plan. We can help you develop a strategy tailored to the specific needs of your operation.

Information provided by Coastal AgroBusiness, Inc.

Keeton Seed Firmers are a product of Precision Planting LLC.
Advance LCO and Quantum for Corn are products of Coastal AgroBusiness, Inc.