Skimping On Fertilizer Is A Two-Edged Sword

CORN ILLUSTRATED: Applying less fertilizer to trim the budget only works if you know soil test levels.

Published on: Mar 4, 2014

One camp of folks preparing for the 2014 season are all about cutting the input budget. You have to have seed and weed control, and everybody knows you need nitrogen to grow corn. That leaves P and K fertilizer as the obvious choices when looking for places to cut the budget.

Most agronomists say that may be OK, as long as you know where your soil test levels are. And, those levels need to be in the good or higher category for each nutrient.

Soils that test low in a nutrient still need fertilizer. University research from across the Corn Belt confirms that when fertilizer levels are low, there is a very good chanced of payback for the application through increased yields in the first year.

APPLY OR PASS: You can save money by not applying P and K, but will it help profitability or hurt it? Most agronomists say that depends largely upon soil test levels in any given field.
APPLY OR PASS: You can save money by not applying P and K, but will it help profitability or hurt it? Most agronomists say that depends largely upon soil test levels in any given field.

Get a soil test
It all starts with soil testing. It may sound like a cliché, but it's true. If you don't know where soil test levels are, you're shooting in the dark without a guiding light.

Tom Stein, a certified crop adviser and manager of the Ceres Solutions branch near Templeton, Ind., says after you review your most recent soil test results on a field, determine if they are high enough to sustain optimum yields without replacing those nutrients.

If you decide they won't do that, or if they will but you want to maintain soil test levels anyway, consider asking your dealer to write a fertilizer prescription that meets your needs, Stein says.

Related: Expect Your Agronomist to Talk About Soil Health Tests

His recommendation is to go with a variable rate application based on actual crop removal. To do this, he suggests using raw data from your yield monitor so that you get the most accurate prescription map possible, tailored to the need of each area within the field where you will apply nutrients.

Remember that crops remove nutrients. How soon you need to replace them depends on where soil test levels are in the soil.