Soil sampling seems to be a forgotten part of any farm operation. Whether that is pasture/hay ground or crop ground, soil samples will give you some very valuable information that can help you get the most out of your farming operation.
Why is information about the soil so important you might ask. Well, the dirt under your feet contains so many different nutrients that affect and determine how grasses and crops grow and flourish. The different micro- and macro- nutrients work together in different ratios to determine the outcome of whatever is being grown. The topic of soil could lead us down a rabbit hole of never ending information, but today we are going to focus on the 5 most important things to look at when evaluating soil samples!

First things first is the pH level of the soil. When soil pH levels aren’t sitting in an optimum range the levels of nutrient availability are being obstructed. Soil pH is the measure of the acidity or basicity of the soil. It is said that the optimal range for a soil pH is 6-7.5. This will help your crops use the nutrients in the soil to the best of their ability.
For organic matter I am going to give you an analogy. Organic matter is the living, the dead, and the very dead. The living are organisms that are alive in the soil like worms, bugs, roots, and etc. The dead are those exact organisms after they have died. They are still there, but decomposing and are being used as food for the living. Lastly is the very dead, which is dead organisms that have essentially wiggled into a part of the soil that can’t be reached by living organisms. This includes spaces like extremely compacted soil or in abandoned spacings left by living organisms. All of those organisms in the soil, whether they are alive or dead, contribute to a higher organic matter. The higher the organic matter the better the soil structure, the better the water holding capacity, the better the erosion control, and the more “free” nutrients from the soil you’ll be able to utilize instead of paying for them in forms like fertilizer. Have you ever been to Iowa and noticed that their soil is typically darker? This is because they tend to have soils that are higher in organic matter and the higher levels of sodium influence the deeper coloring in the soil.

The Cation Exchange Capacity (CEC) essentially tells you how well your soil is going to hold nutrients and how it is going to react to different fertilizers and treatments. The difference between a high CEC and a low CEC will help you determine when and if you should apply lime, nitrogen, potassium, and other related fertilizers. The CEC is also measuring how many cations, or positively charged ions, the soil can hold. Cations can be replaced by other cations which makes them exchangeable. This is good because when you don’t have a sufficient amount of one soil nutrient cation then another one can take its place to aid in the growth of the crop. The more cations your soil has the more nutrients the crops will absorb and there are six common soil nutrient cations which are calcium, magnesium, potassium, and ammonium, hydrogen, and sodium.
Nitrogen is one of the most essential nutrients in the growth of plants. It gives the plant a key source of protein to grow and develop throughout the crop’s life cycle. Since plants can’t utilize atmospheric nitrogen they rely on nitrates in the soil that they absorb through their roots. Nitrates serve as a readily available form of nitrogen that the plant can utilize as it develops. Unfortunately, nitrates are water soluble and easily erode through the soil, which is why you will see operations applying nitrogen fertilizers to their fields through different forms like urea, anhydrous ammonium, dry diammonium phosphate, etc.
The fifth component of soil sampling is looking at the ratio of macro and micro nutrients. This ratio is important because the ones called macronutrients are needed in larger quantities and the micronutrients are needed in smaller quantities. It’s not a matter of if the soil needs any of the nutrients, it's a matter of in what ratio do they need to be applied to the soil in order to have a sufficient amount for the crops to flourish. When it comes down to it, it's kind of like a game on deciding how much of any of the nutrients you should be applying, because too much or too little can harm the plant growth cycle resulting in diseases, reduced growth, yield loss, etc.

For decades lots of farmers just kind of guessed what their soil needed, which a lot of them got good at because overtime they learned how their soil and crops reacted together. With today’s technology and research, soil samples are a fantastic tool to help give a more accurate and exact measurement of the soil health on your operation. In turn this will help you save money on input costs because you know exactly what your soil needs instead of guessing and possibly wasting valuable products. With the way the agriculture economy is today, saving money where you can is very much needed!
Love,
Olivia, Tabby, Gina, & Kendra
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