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Still time to test, apply fertilizer

Early harvest and a long, dry fall usually mean plenty of time to soil test and apply fertilizer. Many of you have applied lime and fertilizer, whether you could pull a soil test or not. Extremely dry soils complicated pulling soil samples.

If you’re still waiting to pull samples but want to get fertilizer applied before winter, what should you do? Here’s advice from the Crops Corner panel, supplied by the Indiana Certified Crop Advisers association. Panel members include Danny Greene, Greene Consulting LLP, Franklin; Ryan McAllister, Beck’s Hybrids, Parker City; and Jeff Nagel, Ceres Solutions, Lafayette.

We waited for rain to pull soil tests. We’re still waiting, but want to take advantage of any decent weather remaining to apply fertilizer. Should we still pull samples and wait?

Greene: If it’s been more than a few years since you sampled, take samples. Then rebalance to bring some levels up and cut back where levels are already high. If you absolutely can’t wait for recommendations, apply to replace for crop removal and build where past results suggested you should. If you have a soil fertility snapshot taken every few years, you have a basis to make decisions in tough sampling years.

McAllister: Well, in my kitchen I have sugar, eggs, flour, vanilla and chocolate chips. I think I will surprise my wife and bake cookies. I don’t have a recipe, but I have the ingredients. That’s no problem, is it? You wouldn’t attempt to bake cookies without a recipe! Throwing away a few dozen cookies won’t break you, but we’re talking your livelihood here. Wait on the “soil test recipe” before applying fertilizer, and take the chance of having decent weather later.

Nagel: It may depend upon how long you’ve been in a good soil sampling program. If soil pH, phosphorus and potassium levels are in optimum ranges, you could apply after tests are pulled, but before you get recommendations. Consider what you applied and adjust future variable-rate applications.

If you’re just starting a soil sampling program or suspect some problems with low or very high levels or low pH, then wait longer for results. Use information to make a variable-rate application to optimize input costs.

Stay flexible

Should I compensate if samples were pulled very dry?

Greene: Keep a record of soil conditions and seasons when samples are pulled. However, I wouldn’t recommend compensating for it. Instead, compare new results with past results and determine if any samples warrant a re-check to confirm the results.

McAllister: Compensating for P and K is not practical. There is no good way to determine when levels of compensation should be employed. Ideally, wait until soil moisture is adequate. A good way to determine this is simple — you shouldn’t have to jump up and down on the probe and spin around. If you get dizzy from spinning, it’s probably too dry!

Nagel: If soil tests were pulled this fall already, recognize that soil pH and potassium numbers could be more variable. Look at historical numbers to see if results seem reasonable. If not, additional testing may be needed.

This article published in the December, 2010 edition of INDIANA PRAIRIE FARMER.

All rights reserved. Copyright Farm Progress Cos. 2010.