By Bob Robb
OK, if you are a food plot kind of guy, you know you need to fertilize to get maximum results. Sounds simple, right? Then head down to the feed store and look at all those different fertilizers. But, what do those three numbers on a bag of fertilizer mean exactly?
“They indicate the ratio of nitrogen (N), phosphorous (P) and potassium (K),” said David Hale, half of the legendary Knight & Hale game calling team. “And they always appear in the same order on the bag, no matter what the number actually is.”
Those numbers simply represent the percentage of each element in the bag. For example, a 10-10-10 fertilizer has equal parts (10 percent) nitrogen, phosphorous and potassium, with the remaining 70 percent filler designed to help spread the fertilizer evenly. In some cases, the remaining percentage also consists of trace minerals and other nutrients that benefit the soil as well. The higher the number, the more of each nutrient in the bag—which means you won’t have to use as much with each application.
OK, fair enough. Now the question is, what’s the right fertilizer, and perhaps more important, how much should you use? According to Hale, a farmer before he became a game callmaker and celebrity, the only way to determine exactly how much you need is with a soil test. “Without this test, you are wasting time and money,” Hale said. “In fact, applying fertilizer willy-nilly can actually harm or even kill your food plots by feeding them too much.”
A soil test is a simple, inexpensive process that tells you exactly how much of each nutrient to put down. Virtually every state cooperative extension office and even seed manufacturers like Whitetail Institute and Mossy Oak BioLogic will conduct soil tests for a small fee, usually under $10. Simply send a small bag of dirt along with a standard form and you’ll receive recommendations for fertilizer and lime applications, usually in pounds per acre. You’ll have to do a little math to figure out exactly how much to put on your plots, but it’s certainly some of the best money to spend on a food plot.
You also need to fertilize depending on the type of plants you want to grow. For example, clover actually converts nitrogen from the air and puts it into the ground, meaning that if you spread additional nitrogen it likely won’t have any benefit to the clover, but it will feed unwanted grasses in your food plot, creating more competition for nutrients, moisture and root space. That’s why it’s a good idea to fertilize clover with a mix higher in phosphorous, which promotes root growth, and lower in nitrogen. Clover and other legumes like beans and alfalfa also benefit from higher doses of potassium, which protects against heat and cold stress and helps protect against diseases. However, grasses like corn, wheat and rye require lots of nitrogen, so a fertilizer with a high first number and lower second and third numbers like 28-4-8 are best for annual grasses.
Just as a soil test will determine how much and what type of fertilizer you need, it will also tell you your soil’s pH level, which is a measure of a soil’s acidity. A measure of 7.0 is neutral; anything lower is acidic while a higher number indicates basic soil. Generally, a pH level of between 6.0 and 7.0 is good for most food plot plants, with 6.5 the best all-purpose pH level. Hale said he believes that lime is even more important than fertilizer because a proper pH level allows plants to take in the nutrients in the soil. “
“If the pH isn’t right, your fertilizer won’t give you the results you will get with a proper pH level,” Hale said. “Make sure the pH level is right before doing anything else.”
Like right about now.