Choosing the right warm-season forage for deer

Soybean with high weedsjpeg Cowpea podJPG Browsed soybeanjpeg

From left, soybeans growing with heavy weed competition. A pod growing on a cowpea plant. Soybeans browsed by deer.

As a natural resource professional, one of the most common questions I receive is, “What food plot should I plant for deer?” The answers to this question are fairly complex because decisions must take into account the crops’ adaptability to soil site index, the landowner’s specific goals and objectives for deer management, and the current condition of the deer herd. Before a supplemental food plot program is initiated, it is important to evaluate and measure herd dynamics to balance the deer population with the surrounding native habitat. Examples of herd dynamics include population density, sex ratio, recruitment rate and age structure.

Warm-season food plots are an excellent place to begin as this season and the planting options provide exceptional nutrition when deer need it most. At this time, bucks are growing antlers and does are fawning. Both tasks are nutritionally demanding for the individual. Among the warm-season forages that are often planted for deer here in Louisiana are soybeans (Glycine max), cowpeas (Vigna unguilata) and American jointvetch (Aeschynomene americana). All these species meet or exceed the nutritional demands of a deer herd. With the many options available, it can sometimes be difficult to weed through the marketing and be sure that what you have selected is truly appropriate for your situation. The purpose of this publication is to shine a little light on common warm-season forages to better equip you in the decision-making process.

Soybeans are often referred to as the “king of warm-season forages.” No argument here. When soybeans and cowpeas are planted side by side in a demonstration plot, he soybeans are clearly the more preferred of the two species at that point in the growth stage, demonstrated by how aggressively the soybeans have been browsed. Soybeans can be established by drilling at 50 pounds per acre or broadcasting at 60 to 80 pounds per acre.

Cowpeas are commonly planted in the Southeast because of their versatility. They will grow in just about any soil condition and don’t require much fertilizer. Establishment can be achieved by drilling at 60 pounds per acre or broadcasting at 100 to 120 pounds per acre into a well-prepared seed bed. Studies indicate that, much like soybeans, cowpeas are susceptible to over-grazing in early growth stages. This is another reason for a complete native habitat management program. This would entail creating diverse plant communities and plant structure often accomplished through various disturbance practices (e.g., logging, disking, herbicides) and then maintaining deer populations at or below the native nutritional threshold.

Cowpeas are a vining legume with relatively weak stems and will produce long pea pods that are relished by deer. Because of their tendency to lodge and grow along the ground it is often recommended to plant a companion plant with them, such as sunflowers, so that the cowpeas can climb upright and remain available to browse. According to recent research conducted on the LSU AgCenter Northeast Research Station, cowpeas become extremely competitive to weeds and grazing pressure once they’ve reached approximately 28 days after emergence. This attribute makes cowpeas an excellent choice for moderate to high deer densities with significant weed pressure. Establishment can be achieved by planting in larger plot areas and keeping the deer herd in check. Cowpeas are among my favorite due to their long planting periods and tolerance to drought. Here in northeastern Louisiana, environmental scenarios often consist of prolonged flooding into May, June and even July followed by droughtlike conditions. Landowners that find themselves in those types of weather patterns should consider cowpeas as their go-to warm-season forage.

American jointvetch is a warm-season annual legume that is often underutilized but can have tremendous impacts in a food plot program. In an LSU AgCenter study, researchers found that when American jointvetch was available in a pine-dominated landscape it composed 33% of summer-fall deer diets. They also found that when compared to other available native forages, American jointvetch was higher in crude protein and was the most digestible. American jointvetch has pinnately compound leaves and can reach heights of 4 to 6 feet. Establishment can be achieved by broadcasting 20 pounds per acre onto a firm seedbed and then covering seed to a one-quarter inch to one-half inch depth. This can be accomplished by the use of a cultipacker across the plot area before and after planting. American jointvetch tolerates wet soils as well as acidic pH levels, making it ideal for heavier clay soils prone to inundation and low levels of pH. American jointvetch also tolerates shade quite well, making it suitable for long, narrow woods rows that will receive a few hours of sunlight each day. There are many options to incorporate American jointvetch into your summer programs due to its environmental versatility and high forage output characteristics. American jointvetch is resilient to overgrazing and is extremely competitive, so it is a good choice for small plot areas with moderate to high deer densities. Don’t overlook this one as a potential prospect for your situation.

We have covered a lot of general ground regarding some of the more common species used in warm-season food plots. There are many other options not mentioned that could be considered for specific situations. Understanding the environmental conditions of your property along with the anticipated impacts of the deer density will help aid you in creating a successful planting. For more detailed information, email or call at 318-649-2663.

There are many soybean varieties out there with many characteristics, and before choosing a variety you should ask yourself several questions:

  1. What is my deer density? Soybeans have a tendency to be over-browsed in their younger vegetative (leaf and stem producing) stages, so if your deer density is high, then planting in small acreage plots should not be considered. If large plots aren’t an option, then soybeans aren’t likely the right option for your situation.
  2. What is my weed density and weed spectrum? In marginal soil types weeds can often be prolific, and they can quickly cause food plot failure. Sites with high broadleaf weed densities are where soybeans are advantageous because they lend themselves to numerous herbicide options that will aid in reducing competitive weed species.
  3. What time of year am I wanting to make an impact with nutrition? The answer to this question might be the deciding factor in choosing either a late maturity group forage variety or a more commercial variety intended for row crop use. Forage soybean varieties with indeterminate growth habits will continue vegetative growth later into the growing season, producing high quality forage. A typical southern row crop variety will be an earlier maturity group (maturity group 4 or 5) and move from being vegetative to reproductive earlier in the growing season, causing a decline in overall palatability and nutrition of the leaves. If the goal is to provide high-quality nutrition late in the growing season while native plants are beginning to decline, then a forage variety should be considered. If you want to extend the life of your soybean plots by providing grain throughout the fall and winter months, then maybe a higher-yielding commercial variety is more suited for your situation. Either way, soybeans make an excellent warm-season forage. For more information, check out the LSU AgCenter 2020 Soybean Variety Yields and Production Practices Guide at

Luke Stamper is an assistant extension agent for wildlife for the LSU AgCenter in the Northeast Region.

6/29/2020 9:15:22 PM
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