How Well Do You Know Your Soil?

Feb 21, 2022


Fertilizer investments require soil nutrient knowledge
If you are going to spend hundreds of thousands of dollars on your farming business, it’s a good idea to know a lot about it, and that “knowing” should start with your farm’s soil, according to Nick Schaps, Federated agronomy sales rep at the Ogilvie location.

Although your Federated Agronomist or your “favorite fertilizer guy” may provide recommendations for your farm, the final decisions rest squarely on your shoulders. Being able to interpret soil test data, ask good questions, and intelligently assess the recommendations you receive are a good way to potentially “gain more yield – and perhaps save money,” said Schaps, again highlighting the thousands of dollars growers put out for fertilizer each year.

Federated is committed to helping growers get the most bang for their fertilizer buck and accurate soil tests are a critical part of that effort. Plus, “there are some key points about soil tests that most people don’t look at closely enough,” said Schaps.

Carefully note these three factors when you get your soil test results:

1. Soil pH. When the pH is at the right level, soil nutrients are most available to the crop. “This should always be the first thing you look at on a soil test,” said Schaps.  A pH level of 6.8 is ideal for most crops. If pH is below 6.3, add lime. (High pH levels – which aren’t a big problem in most of Federated’s service areas – may indicate a drainage issue; tiling a field can help with those issues.)

2. Base saturation. This is the ratio of five key nutrients in relation to each other: potassium, magnesium, calcium, hydrogen, and sodium. Schaps said, “Don’t let someone tell you base saturation isn’t important, and here’s why.” A soil test could, for example, reveal high potassium levels, but if the soil test also shows high levels of magnesium, calcium, and hydrogen, the potassium may not get into the plants (which can be proven by plant tissue analysis). Looking at the potassium levels alone won’t provide an accurate picture of what the soil needs.

The key is to understand base saturation and use it along with other information from the soil test. Here are examples of good ranges for soil elements.
  • Potassium – 4% to 8%
  • Magnesium – 12% to 25%
  • Calcium – 65% to 80%
  • Hydrogen – less than 10%
  • Sodium – less than 1%
“If you find these ranges are off in your soil, work with your Federated Agronomist [to find] methods of balancing them,” said Schaps.

3. Cation Exchange Capacity (CEC). This is a measure of the soil’s holding capacity. The higher the number, the more water, nutrients, and pesticides the soil can hold. 

One of the most basic uses for CEC is to measure nitrogen (N) capacity. Multiply your CEC by 10, and “that will tell you roughly how much nitrogen your soil can hold at any one time,” said Schaps. 
 
He offered this example:
 
“Let’s say your CEC is 15. That means your soil can hold about 150 lbs. of N. However, you may need to apply 200 lbs. for your yield target. Should you do it all at once? No, you will need to split-apply the N,” said Schaps, adding that it would be good to consider a controlled-release N product, such as SuperU™, or a stabilizer coating such as Factor Plus™.

As soon as the ground thaws, get your soil tests done for 2022, “and you will be one step closer to keeping your farm efficient and profitable,” said Schaps. “A small investment in good soil tests will really pay off in managing inputs,” and although pH, base saturation, and CEC may not be “glamourous,” [these tests] are “just as important as finding out your levels on N, P, and K,” he said.
 
Fertilizer is a costly investment, but commodity prices are high this year. Talk to your Federated Agronomist to discuss ways to make 2022 the year to maximize crop potential.

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