Posted 27 April 2015. PMN Crop News.
Back to Basics With the Hefty Brothers: Spring Soil Testing Helps Get Most for Your Fertilizer Budget
Source: United Soybean Board Press Release. www.unitedsoybean.org
Chesterfield, Missouri (April 14, 2015)--Is it OK to soil test in the spring? The simple answer is YES; spring soil testing is fine. However, itís not quite that simple.
Fall soil tests equal spring soil tests if you test late in the fall, your ground then freezes rock hard immediately after that, and in the spring you test as the ground is thawing. If you are in an area with a mild winter or if you test early in the fall or late in the spring, your fall vs. spring results could vary significantly. For example, you may get a bunch of rain in between, which could leach out nitrates, sulfates and boron. On the other hand, you could get more organic matter mineralization. And if you donít have a crop (or weeds) growing over the winter, your soil test levels could actually rise in the spring, compared to fall.
Here is my number one message for you today: Donít just do what youíve always done.
At least soil sample one or two fields on your farm. Get the results. Look at the recommendations. Learn what these things mean.
I am almost positive that your fertilizer dollars could be better spent, at least in areas on your farm. Is it possible that taking $10 out of your nitrogen budget and investing that in potassium, phosphorus, sulfur or micronutrients could pay? Is it possible you are just flat-out over-fertilizing? Is it possible that across the board you are under-fertilizing?
You donít know, and I donít know unless you pull some soil tests and get a complete analysis of those samples. Isnít it worth a couple hours and a few dollars to find out?
Best practices for soil sampling
What we typically advise is that you pull your soil tests at the same time of year each time you sample. That way you have taken out one of the variables, meaning you should get a more accurate read on whether or not your fertility levels are truly rising or falling over time.
Personally, I would prefer to see you test in the fall. That way, you can apply fall fertilizer more accurately. That also gives you all winter to better analyze and scrutinize your soil tests.
All that said, itís springtime now, so if you still need to test, we encourage you to get it done. The number one question we had all winter was, ďHow can I cut my expenses in 2015?Ē Letís face it, itís fun to save 10 cents on glyphosate, but glyphosate costs a grand total of $4 or less per acre. When you invest $100 or more per acre in fertilizer, where do you think the big savings will come from?
Reading the results
If you donít know how to read a soil test, hereís our best advice for you today:
1. Go to agphdsoiltest.com today. Set up your fields, and at least take one or two of those fields and soil sample them this spring.
2. Pull your own soil tests in those fields using the free Ag PhD Soil Test app for your smartphone. This allows you to grid sample your own fields quickly and easily. If you only sample a couple of fields, it should take no more than a couple hours to pull all the tests and send them to the lab.
3. You will get your sample results within a week. When you do, thoroughly look through the tests and talk to a Hefty agronomist or directly to Darren and me on Ag PhD Radio (844-442-4743). In addition to getting the soil labís recommendations, you will get our recommendations for free as part of the Ag PhD Soil Test program.
4. Once you have your soil-test results, you can use the program to make variable-rate-fertilizer-application maps and controller files that can be downloaded and used in your equipment.