Most forage producers realize there are benefits of providing plant nutrients to their pastures, hayfields, and other cropland on an annual basis. Often times the fertilizer application is made without knowing what nutrients are currently in the soil. Fertilizer isn’t cheap, and a soil sample will help make the most of the money spent on fertilizer. Forage that receives the proper nutrients will have a higher quality than forages that don’t. Proper nutrients also impact the actual stand of forage. Most are familiar with the decline in Bermuda grass as the potassium levels drop. Forage crops utilize as much potassium as they do nitrogen and if we don’t supply the sufficient amounts of potassium, levels can quickly become deficient.
The pH level in the soil is just as important as the nutrients in fertilizer. If the pH falls out the desirable range, the plant can no longer utilize the nutrients applied. This means the money spent on fertilizer was a waste. Forage crops can vary in their optimal pH level but most grasses do well with pH levels between 6.0—6.5.
The best way to determine the soil nutrient and pH level is through soil testing. Soil samples can be sent to the University of Georgia Soil Testing Lab by dropping off samples as your local Extension Office. Soil samples average $6 each. It’s recommended to take one sample for every15 or 20 acres. If you do the math, that equals $.40 an acre. 40 cents an acre on a soil sample is the cheapest and most beneficial thing you can do on your land!
Just keep in mind that the results are only as good as the sample submitted, so be sure to collect numerous core samples from the area being tested, mix the core samples together thoroughly, and then take the sample to be sent to the lab from that mixture. Previous sampling studies have shown that the number of cores required per composite sample varies with the size of the area being sampled. For example, 20 cores were required for a 20-acre field, 15 cores for a 10-acre field, and 10 cores for a 5-acre field.
Forage growth and quality vary with the nutrients applied. pH has a great affect on how plants use nutrients. Don’t guess. Soil test! You’re spending money blindly without sampling soil to determine nutrient needs.