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Soil Fertility Basics

The ideal soil pH not only helps your food plots perform better, it can provide your deer with more minerals essential for antler growth

Soil pH Fertilizer Course 101 Soil Testing

Soil pH

Soil is measured by the pH scale. The pH scale runs from 1 to 14, with 1 being exceptionally acidic and 14 being exceptionally alkaline. Most soils are between 4.5 and 8.5. Soils in the eastern half of the country tend to be acidic while soils in the High Plains and West are often the opposite. There are always exceptions.

Why is pH important for food plots? Quality forages generally perform best in a neutral soil pH (6.5 to 7.5). At a neutral pH level, forages can best utilize the nutrients and minerals in soil. When the soil is overly acidic or alkaline, the plants aren’t capable of absorbing many of nutrients. A neutral soil pH does many things, including:

- Allowing grasses and legumes to perform at their optimal level, producing more leafy growth, which can provide more quality grazing forage and provide more yield.
- Allowing plants to maintain health, which can result in plants living longer and performing better in adverse weather conditions.
- Providing optimal growing conditions, which often allows grasses to out-compete weeds, so pasture owners have fewer weed challenges and herbicide costs.
- Allows your forages to absorb more vital minerals in the soil, minerals such as phosphorous and calcium, which are the building blocks of antlers.

Although there are exceptions, most hunters will have plots soils in the acidic range. Lime neutralizes acid. Get a soil test. The results will indicate how much lime must be applied to reach the ideal soil pH. Pastures often require several tons of lime per acre. But don’t let that scare you. Lime is often less than $50/ton from many parts of the country.

There are two basic forms of lime – agriculture grade and pellet lime. Agriculture lime is in powder form and is bought in bulk, often delivered and spread with a spreader truck by your local farm supply store. Pellet lime is what most people know as bagged lime at lawn and garden centers. This lime is usually much more expensive and is usually only used for small fields that don’t require bulk deliveries.

Lime can take up to six months to fully dissolve into the soil and correct soil pH, so it is beneficial to take a soil test and apply lime, if needed, far in advance of planting.

Just remember, creating the ideal soil pH is more important than fertilizer. You can fertilize often, but if the soil pH is too low, the plants won’t be able to use much of that fertilizer, and the fertilizer will be lost or used to promote weed growth. The adjacent chart shows what nutrients are available to plants according to the pH level. Notice how much more mineral can be absorbed by plants with a neutral soil pH.

Soil pH Fertilizer Course 101 Soil Testing

Fertilizer Course 101

Fertilizer is made up of three basic minerals – nitrogen (N), phosphorous (P) and potassium (K, also called potash). Fertilizer analysis is always given in that order – N, P, K. For example, 10-10-10, is a common fertilizer. The numbers indicate the percentage of each mineral in that bag. So if a 50-lb bag is 10-10-10, there is 10 percent of each mineral in that bag. That would mean a 50-lb bag of 10-10-10 fertilizer has 5 pounds each of N, P and K. A 50-lb bag of 20-10-10 would have 10 pounds of N, 5 pounds of P, and 5 pounds of K.

What is important about N, P and K? Just remember this simple saying, “Up, down, and all around.”

- N promotes increased upward growth – leaf growth. N can also increase protein levels and creates darker green leaves.
- P promotes downward growth – roots. Plants are only has healthy as their roots.
- K promotes all around health, including increased winter hardiness.

A soil test will indicate how many pounds of each mineral are needed for optimal grass growth. If you have a large plot, ask your local farm supply store to mix the fertilizer according to your soil test, and they can deliver and spread the fertilizer or you can rent a spreader buggy pulled behind your truck. For small plots, you can simply use bagged fertilizer. Common fertilizer types, such as 10-10-10 or 13-13-13 usually result in adding more phosphorous and potassium than needed (wasting money on fertilizer).

It's beneficial to apply smaller amounts of fertilizer more often, rather than one giant application. For example, applying half of the plot’s fertilizer needs in the spring and the other half in late summer is better than applying everything at once. Your plot’s forages can only use nutrients so fast. Often, one large fertilizer application will result in much of the fertilizer being dissolved by rain or ground water and flowing into creeks.

Legumes are plants that produce their own nitrogen – clovers, alfalfa, beans, peas, birdsfoot trefoil, peanuts and other plants are legumes. Grasses (including corn, cereal grains and sorghum), herbs (including chicory), forbs (including small burnet) and brassicas all require nitrogen for optimal growth.

Soil pH Fertilizer Course 101 Soil Testing

Soil Test

To take a soil test, take a garden shovel and a sandwich bag out to the plot. Take several samples from each acre or small plot. A sample is nothing more than getting a small amount of soil from a few inches deep. Label the bag so you know which plot the soil came from. You only need to fill one sandwich bag with soil samples from each plot.

Take your soil samples to you local agriculture extension office. They may charge a small fee to send the soil to a lab – many provide the service for free. The results will likely be available at the extension office in two to five weeks.