Soil Sampling Pays

A common question asked by hunters and wildlife managers is, " I am only planting a food plot, do I need to soil test and apply lime?" The answer is "It depends". If you want to maximize the productivity of the food plot and provide as much forage as possible for the dollars spent, the answer is YES. If you only want to plant a green spot to hunt near and do not care if it is nutritious and do mind-wasting money the answer would be I GUESS NOT.

All plans to plant good food plots should include a soil test. Soil testing is the basis for your decision about how much fertilizer and lime to apply. Many producers soil test only to determine the need for lime. As a habit, they apply the same amount of fertilizer every year without soil testing. Is this a good habit? Normally it is not. Let me explain.

Lime is extremely important to you because it increases fertilizer efficiency. How would you feel if you gave $500.00 to a charitable cause and later discovered that they had used only 50 percent of your money for charity and the rest was tied up and lost to administrative costs? Yet, this could be happening to you when you apply fertilizer to soils with low pH values. Your crop of winter grass or other plant material can only use what does not get tied up in the soil chemistry. When the pH is low (acid), fertilizers are chemically "bound" in the soil profile and are not totally available. Depending on how acid the soil is, you could be suffering a loss in efficiency of 30 to 60 percent of the nitrogen, phosphorus and potash you apply.

A study of the chart above will reveal that nutrients such as calcium and phosphorus are not available at the maximum rate until the pH is up to 6.5.

It does not make sense to apply fertilizer to crops and lose as much as 50 percent of your investment. It's not that the nutrients are not there; they can be there just not totally available to the plant. Lime will simply make your nutrients more available to the plants, increase efficiency and save you money. It is not too late to apply lime.

Bulk Lime can normally be spread for $40 - $50 per ton.

The best time to apply lime is any time you can get a truck into the field. The very fine particles begin to neutralize acidity almost immediately and some benefit is realized within the first two months. However, the remainder of the larger particles break down more slowly and can take as much as 6 months to take effect. A good lime application will usually last for 3 years.

There is another way the soil test can save you money. If an area has been fertilized on a regular basis and there is no crop removing the nutrients ( hay, corn, etc.) from the field or food plot, these nutrients can build up on the site to high levels. A soil test ranks your phosphorus (P) and potash (K) level as very low, low, medium, or high. Nitrogen is recommended for the particular crop and is not really based on any particular reading of the soil test. If your soil tests high for P, then no phosphorus fertilizer is required. The same goes for the potash as well. Could you save money by applying fertilizer according to soil test? Consider the following true story as an example.

A local wildlife manager who plants 20 acres of food plots recently evaluated his soil tests. Due to a good liming and fertility program, all of his plots were OK for lime and almost every one of his food plots tested HIGH for P and K and very little of this type of fertilizer will be required. Many persons apply 13-13-13 at 300 pounds or more per acre without the benefit of a soil test. A routine application of 13-13-13 at 300 pounds per acre would have cost him $690 for the 20 acres. He can apply fertilizer according to soil test for less than $100. That is a significant savings of money ($30 per acre) and labor. If you plant only one or two acres, the savings are still there but of course not that great.

For more information on soil testing, contact your local Mississippi State University Extension Service County Director for instructions and boxes. The $6.00 per sample fee will be well spent.