Get the Dirt on Dirt-
Great food plots start with great soil.
By Matt Coffey
Courtesy of the National Wild Turkey Federation
Although the spring season has passed and deer hunting is on the minds of most hunters this time of year, now’s not the time to neglect those food plots. With a little patience —along with some sweat equity — your spring food plots could be even better than last year.
We talked to some of the experts at the National Wild Turkey Federation to get the scoop on dirt, because, let’s face it, if your soil isn’t properly prepared, then your crops suffer.
“The first thing any land manager wanting to plant a food plot should do is test the soil,” said Scott Vance, director of conservation field operations for the NWTF. “You can save yourself a lot of time — and money — by figuring out what exactly your soil needs.”
A soil test is available from your local extension office and will determine if your soil is acidic or alkaline, based on the pH scale. The pH scale runs from 0.0, which is the same as battery acid, to 14, or liquid drain cleaner. Ideally, you want your soil at a pH of 6.0 to 7.0, right in the middle.
“Most food plot plants grow best at a pH of 6.0 to 7.0,” Vance said. “At pH levels lower than that, the soil does not provide the necessary nutrients to the plant even if you add them through fertilizers. Research has indicated that you may be wasting as much as 40 percent of your added nitrogen fertilizer when the soil pH is below 6.0. With fertilizer prices as high as they are now, most folks just can’t afford to do that.”
After you get your results back from the extension office and have an idea where your pH stands, you can then add lime or fertilizer to bring your number up or down, depending on where your soil tested.
If the soil test suggested adding lime to your soil, it should be tilled in to a depth of 4 to 6 inches for best results. A good rule of thumb is to add 1 ton of lime per acre to achieve the desired pH point increase. Most sandy loam soils are going to require at least 2,000 pounds of lime per acre, and most clay soils are going to require a whopping 5,000 pounds of lime per acre to achieve the ideal pH level.
“This may sound really time consuming and expensive, but compared to fertilizer, lime is very inexpensive and most agricultural cooperatives offer it very affordably,” Vance said.
One of the problems with heavy lime applications is that it will take the soil more than a year to incorporate the lime. Therefore, you should plan to add lime at least 8 to 12 months prior to planting your food plots for optimal results.
Soil tests are designed with the assumption that the soil sample was taken at a total depth of 6 inches and the liming recommendations are designed to increase the soil pH to 7.0 in one acre of soil that is 6 inches deep. If you place the recommended amount of lime only 2 inches deep, then you’ve over-limed your food plot and have made the situation worse by creating a high pH soil. The key to making sure your food plots receive the correct amount of lime is to make sure you cultivate to a depth of at least 4 to 6 inches. By going the extra inch or two when you till, you can make sure your food plots get the recommended amount of lime throughout the entire area.
While getting the deep soil pH too high is a rare problem for food plots, it is worth noting that very high pH soil can cause stunting and stresses the plants in the early stages of growth. When the roots hit the lower pH after being in a higher pH soil on the surface, it is like being in a hot shower and having ice water poured down your back.
If fertilizer is recommended by the soil test, it will tell you how much nitrogen, phosphorus and potassium (a.k.a. potash) you will need per acre. Nitrogen is the first major element responsible for plant growth above ground. With a good supply of nitrogen, plants grow sturdily and mature rapidly, with rich, dark green foliage. Without enough nitrogen plants grow slowly and tend to be yellowish or light green.
The second major element in plant nutrition is phosphorus. It is essential for healthy growth, strong roots, fruit and flower development, and greater resistance to disease. A lack of phosphorus will result in poor yields for plants like corn, soybeans and sunflowers. And finally, potassium oxide helps plants resist disease and protects them from cold and dry weather by preventing excessive water loss.
If nitrogen and/or potassium are recommended by the soil test you should add them right before, or even after, the food plot is planted and starting to grow. Phosphorus moves through soil very slowly, so it should be added early and incorporated into the soil. A good practice in phosphorus-poor soils is to apply the phosphorus in the appropriate amount at the same time you put out your lime. This gives you to time incorporate it and gets the soil chemistry right before you plant your seeds.
Fertilizer is expensive, but it’s an integral part of the equation. Don’t scrimp on lime, fertilizer or quality seed and you’ll have food plots to be proud of this year.