Depending on your wildlife habitat focus you may be looking to enhance existing native habitat, or you may be thinking of adding other things such as food plots or tree plantings. It is generally safe to say that on sites where agricultural practices have NOT been previously implemented that you likely have the soil properties and natural fertility levels to promote more native vegetation. Generally native, perennial vegetation and trees have adapted to being able to gather nutrients from deeper in the soil profile and to utilize the nutrients naturally present. Annual agricultural crops as a general rule have higher input needs in terms of fertility and may be also hampered by soil pH. How do you get a reading for what may be lacking in your soil and the amount of fertilizer and possibly lime needed to raise pH levels - a soil test.
Soil testing is a fairly straight forward process. Soil can be collected with a clean shovel, avoid inaccurate readings by removing soil stuck to the shovel between sampling locations. Samples are taken from a specified soil profile, such as from the ground surface to 8" deep or profiles can be taken from deeper depths depending on the crop you may be planting. You can also use a manufactured soil probe to collect that same sample. Probes are handy if you have multiple samples to take. Relatively little soil is required to have a test run. I would say a cup of soil is more than likely sufficient. Soil samples can be kept separated in plastic Ziplock bags that are labeled so that you know which test results came from which location. Overly wet soil samples should be allowed to dry out a bit before sealing the bag. Those samples are then submitted to a testing lab. There are many different places that will run a soil sample. Many land grant universities have a soil testing lab available to the public or there are commercial labs such as Ward Labs in Kearney, NE. Your local county extension agent can probably provide a list of the closest testing labs.
The testing labs can run a variety of tests on your soil sample. For most of us our needs can be met with the simplest tests. Knowing the major soil fertility levels of Nitrogen, Phosphorus and Potassium as well as pH (with a lime application recommendation) is going to get us good food plot and tree planting results. High production agriculture requires more refined testing to maximize crop production. Micronutrient, organic matter and CEC testing can also be done. Some of those results can be handy when monitoring soil conditions over time, but typically aren't required from a food plot or tree planting perspective. The last time I looked basic, professionally conducted soil testing done by a lab is anywhere from $12 to $24 / sample. The number of samples you submit comes down to the size of you planting area and how much observable variance there is in your soil. If soil is fairly consistent on your property and you have some planting history, then I think a sample for every 3-5 acres is sufficient. If you know that the soil within a food plot varies from one end to the other you are probably better served by sampling in more locations to be able to get a clearer picture of what fertilizer or lime applications you may need to do. Let's face it seed, fertilizer and fuel are not cheap, our time is not free. Soil testing lets us make appropriate applications if needed to help us grow a productive plot. In the ideal situation, with minimal tillage and good crop selections we can reduce the amount of synthetic fertilizers we need to apply over time. Getting soil tests done prior to planting trees is also valuable. It is much easier to incorporate amendments into the soil prior to planting than to do so after the trees are planted. Phosphorus is known to move very slowly through the soil profile, but it is essential for good root growth. So if we wait to add phosphorus after the trees are planted it is going to take multiple years for it to work down into the root zone.
In some instances it may be beneficial to collect soil samples every year, but in all honesty unless you are making large changes in what crops you are planting you can probably take a test every other year or longer. If you see very little change to your test results from one sampling date to another you can wait longer between tests. It is important to take your soil samples in the same time of year for consistent comparisons. Most often soil samples are taken in later Winter prior to Spring or Summer planting season. In a future blog we will look at the finer points of reading the soil test results and application methods for fertilizer and lime.