Don’t Lose a Good Plot

By Dr. Wiley Johnson

            Many things can contribute to the untimely loss of a good plot so a continuing concern of our growers is finding the proper program to maintain a thriving food plot of Imperial clover or Alfa-Rack. Let’s look at these and develop a sensible maintenance program.

            The most common limiting factor is inadequate or unbalanced fertility (including lime). A problem here can be detected and remedied by getting a soil test by a reputable laboratory. If there is a fertility problem it will be identified by the soil test and can be corrected by specific fertilizer or lime application. Legumes like Imperial Clover and especially Alfa-Rack require a nearly neutral soil pH of 6.5 or higher.. Soils that are too acid lead to premature decline. This occurs far too frequently.

The most common fertilizer element contributing to stand decline is potassium. Legumes have a high potassium requirement and are less efficient in getting potassium from the soil than many weeds and most grasses. This means that weeds and grasses can thrive in a soil with inadequate potassium for legumes. Do not apply a high nitrogen fertilizer to a leguminous food plot, nitrogen fertilization does not benefit the legume but will stimulate the competitiveness of any associated weeds and grasses. This also can contribute to early legume stand loss. Some examples of low nitrogen fertilizer are 0-20-20 and 6-24-24.

            Do not allow excessive growth to accumulate. -- herbage produced should be utilized as much as possible. Often the deer herd will do a good job of herbage utilization. Try a wire cage to see how growth is being removed. There will be times, however, when growth exceeds what can be removed by deer. Utilization by domestic livestock is great if it is feasible. This may not be a viable option for many reasons, but take advantage of this option if you can. Mowing is good. Perhaps you can make hay but more likely the cut herbage will be left in the swath to dry and eventually decompose. This is okay provided you don’t smother the plants with too much cut growth. In any event, it is better to mow and chance damage than to let growth accumulate, lodge (fall over) and most surely cause damage.

            Plant diseases can also cause stand decline. Several viruses can infect legumes and cause decline. Viruses are spread from infected plants to clean ones mechanically (mowers or grazing animals) or by an insect vector. Aphids are commonly the carrier but others may be involved. Plant viruses don’t generally kill but they so debilitate plants that normally tolerable stress will cause death. The most effective control is to avoid planting legumes near potentially infected plants, like an old declining stand. In such a case, completely destroy the old stand by disking before making a new planting. Isolation of most food plots probably helps us avoid serious problems.

            Several common and destructive diseases are caused by soil-borne fungi. These disease organisms are found in most soils and can cause disease whenever environmental conditions are favorable. Fungal diseases are commonly spotty. Diseased or dead plants often occur in well defined areas scattered over the food plot. Crop rotation and removing excessive growth are the best preventative measures. You don’t cure a sick plant--you try to keep it from being infected.

            Serious insect problems are rare in an established stand. However, occasionally insects such as armyworms, leaf hoppers, aphids or blister beetles can build up numbers that require control measures. Be aware, but do not be overly concerned with insects.

            Now let me summarize my experiences and thoughts on maintaining productive Imperial Clover or Alfa-Rack plots: