Warm Season Food Plots
Planting supplemental forages is a popular method of attracting deer. However, one must remember that food plots should not be used as a "quick-fix" or substituted for proper habitat management practices. Food plots can be used to supplement essential nutrients that may be lacking in native forage. They are also valuable as a tool to facilitate harvest and to increase non-hunting viewing opportunities. Regardless of the purpose, consideration must be given to each of the following to insure successful establishment:
- Site Selection
- Soil Analysis
- Liming and pH
- Forage Selection
Warm season supplemental plantings are rated more important than cool season plantings by some biologists, but rarely are they given even equal consideration. Recommended ratios of warm to cool season plantings approach 60:40 in many comprehensive supplemental planting programs. Quality forage in the summer months is important because of the typical decline in native forage quality and the additional nutritive demands experienced by lactating does. Selection of an effective warm season mixture or single forage species can be a challenge. Forages must be selected that are both highly desired by deer and capable of producing an abundance of quality plant material. Warm season forages should also be able to tolerate moderate browsing pressure without significant damage to subsequent plant growth. Cost of establishment, protein content, and even the amount of digestible protein are also important considerations.
The purpose of this article is to provide Mississippi sportsmen and landowners a guide for simply and economically establishing effective warm season supplemental plantings for white-tailed deer.
When choosing a site to use as a food plot, the primary consideration should be soil productivity. Productive soils are those that have adequate fertility, moisture, drainage, and texture. However, other factors such as adequate sunlight, accessibility, size, shape, and arrangement must also be considered.
A good rule of thumb is to make plots a minimum of one acre in size, irregularly shaped, and at least 1 mile apart. We recommend that 3-5% of an ownership be devoted to supplemental plantings that include a diversity of cool season, warm season, and permanent forages.
If land ownership prevents the establishment of food plots in ideal locations, acceptable alternatives may include existing openings such as logging decks, fallow fields, utility right-of-ways, fire lanes, and logging roads. However, the establishment of supplemental forages adjacent to public roads is not recommended because of the increased potential for deer-vehicle collisions and poaching.
Most sportsmen accept the necessity of proper fertilization for optimal forage growth of supplemental wildlife plantings, but rarely do they consider liming or soil pH. The two components, fertilization and pH, work together. Proper systemic uptake of fertilizer is diminished if soil pH is low. For example, if soil pH is around 4.5, close to 80% of the money you spent on fertilizer is wasted. In addition, important soil nutrients such as zinc, manganese, and iron are either unavailable or toxic to some plants if soil pH is not correct. Farmers have long recognized the importance of this relationship. If the wildlife manager of today is to efficiently utilize the soil and produce maximum amounts of quality forage at the most economical rates, he must learn from the successful farmer.
Begin supplemental wildlife plantings by soil sampling several months prior to planting time. The Mississippi Cooperative Extension Service is a valuable and competent source for soil sampling information, analysis, and interpretation. They can provide you with instructions, a soil sampling kit, and have samples analyzed at a cost of $6.00 each. When you receive your soil analysis, you will be provided with specific recommendations for liming and fertilization.
Liming and pH:
Soil pH is a measure of the acidity or alkalinity of the soil. This measure ranges from 1 to 14, with 7 considered neutral. Any value less than 7 is categorized as acidic, while values greater than 7 are alkaline. Normally, soils will not be more acidic than 3.5 or more basic than 10. Most soils in Mississippi, which have not been previously limed, will be moderately acidic (usually around 4.0 - 5.0) due to humid conditions and the decomposition of leaves, twigs, and other plant materials. The goal of the wildlife manager should be to achieve a soil pH of 7.0. A value of 6.7 - 7.0 will net maximum productivity, especially on legumes and, to a lesser extent, on cereal grains such as wheat and oats. Proper inoculation of legumes is even more critical on acidic soils because the bacteria which aid legumes in fixing nitrogen are more limited on acidic soils.
Your soil analysis will be returned with site-specific recommendations on lime application rates. Do not be surprised if you receive a recommendation of 3 tons of lime per acre on some of your sites which have never been limed. (In the absence of soil testing, a rule of thumb for lime application is to add 2 tons per acre every third year.) You may also learn that some types of soils require more lime than others to achieve the same result. Clay soils will typically receive higher recommended lime application rates than some of the more sandy soils.
There are many liming materials available on the market. Each of these materials will have varying efficiency ratings. The only way to be sure of what you are getting is to deal with a reputable dealer. For simplicity, we will limit our discussion to powdered and pelletized forms. The powdered form is the most economical. The drawback to the powdered form is that a commercial spreader truck must be able to access the planting site. But, if access is not a problem, this would certainly be the recommended method of application. You will get the most benefit from the lime if it is applied and disked into the soil up to three months prior to planting time. Adequate soil moisture will also increase the ability of the lime to increase soil pH.
On small areas or on plantings which are inaccessible by the spreader truck, pelletized lime can be utilized. This form of lime is packaged in 50-pound bags. Accompanying this price is the added burden of uniformly applying the pelletized lime on the planting site. This application is normally made with a fertilizer/seeder spreader attached to a small farm tractor. Smaller electric versions of the seeder are now available as ATV attachments. The opportunities to utilize an ATV and assorted attached implements for disking, seeding, fertilizer/lime application, harrowing, herbicide application, and even culti-packing are creating situations where supplemental wildlife plantings can be incorporated in remote areas of a landowner's property.
Intelligent and economical fertilization of supplemental wildlife plantings will consist of applying a specific amount of three basic elements. These elements are expressed as nitrogen (N), phosphorus (P), and potassium (K). They are usually expressed in numerical form, such as the standbys 13-13-13 and 6-8-8. In these mixtures the number is actually the percent of that particular element in the mixture. For example, in the 13-13-13 mixture, the first 13 is the percent of total nitrogen, the second 13 is the percent of available phosphorous, and the third 13 is the percent of available potassium. These nutrient values can be 0, so do not be surprised to see a recommendation of a mixture such as 0-46-46 on a soil analysis form.
Local feed stores do not carry every combination of fertilizer mixtures. However, larger dealers will custom blend almost any mixture you request. Allow them several days notice to prepare your mixture. If custom blending is not possible, you can adjust pre-mixed combinations to fit most of your basic needs. For example, 5-10-10 supplies the same equivalent mixture as 10-20-20. But, where you would apply one ton of 5-10-10/acre you would only need to apply 1 ton of 10-20-20.
- Legumes fix their own nitrogen so they do not require nitrogen in the fertilizer mixture after stands are established in the plots.
- In the absence of a soil test, "rule of thumb" fertilizer applications are available for most forage species.
Combination plantings will reduce the risk of total crop failure due to insects, disease, or adverse weather since different species grow and mature at different rates. Plants are most palatable, and subsequently most nutritious, when they are actively growing. However, as plants mature, fiber content (lignin) increases and protein levels decrease.
Recommended Warm Season Annual Legumes:
Iron clay cowpeas are highly recommended. Production trials on wildlife management areas in Mississippi yielded 65,000 to 105,000 pounds of high quality forage per acre. In the same trials, crude protein measured 19.8% for the total plant. Most biologists consider 15-16% crude protein to be optimal for deer growth and maintenance. For green leaves only, the part most preferred by deer, the value was an exceptional 28.9%. An additional benefit of cowpeas is an apparent avoidance of browsing pressure by deer during early stages of plant growth. This allows cowpeas to be produced in areas where high deer densities would prevent the establishment of other warm season legumes. Moreover, when the cost per pound of forage produced is considered, cowpeas outperform most other warm season legumes.
Soybeans are also highly recommended annual legumes. Our wildlife management area production trial value was approximately 45,000 pounds of forage per acre, with 20.9% total plant crude protein content. However, due to their high desirability in the two-leaf stage, deer can inflict serious plant, and subsequent crop, damage even in areas of low to moderate deer densities. A benefit of soybean selection is the availability of Roundup Ready varieties that can be utilized in areas where grass and weed competition is a chronic problem. Late-maturing (Group VII) or forage (e.g., Tyrone) soybean varieties should be chosen to maximize production and utilization throughout the summer months.
Alyce clover is not actually a true clover, but it is an erect annual summer legume with a thin stem, pink flowers, and rounded leaves. Height at maturity can approach 4-5 feet. Our tests showed its production values ranged from 18,000 to 20, 000 pounds per acre. Total biomass crude protein exceeded 16% on all sites, with a maximum of 17.6%. Alyce clover exhibits poor seedling vigor, but can tolerate even heavy browsing pressure during later stages of growth.
American jointvetch, also known as deer vetch or Aeschynomene, is an annual warm season legume native to the Deep South. It is an erect plant approaching 6 feet in height at maturity. Production tests yielded a maximum value of over 43,000 pounds of forage per acre, with 13.4% and 20.7% crude protein for whole plant and leaf samples, respectively. A benefit of jointvetch is that it tolerates wet, relatively infertile, and moderately acidic soils. In addition, it is also quite shade tolerant, and therefore can be used in locations unsuited for other forage species. The primary disadvantage of jointvetch is its establishment cost when compared to other warm season legumes.
Recommended Warm Season Annual Legumes:
SPECIES PLANTING DATES SEEDING RATE* FERTILIZATION RATE AT PLANTING** Cowpeas April - June 60- 90 lbs/ac 100 lbs/ac of 10-20-20 Soybeans April - May 60-100 lbs/ac 300 lbs/ac of 10-20-20 Alyce clover May - June 15-20 lbs/ac 200 lbs/ac of 10-20-20 American jointvetch May - June 20 lbs/ac 300 lbs/ac of 10-10-20 * Based on broadcast application of single species; adjust combination rates proportionally. ** Contrary to information found in most planting guides, we recommend a moderate amount of nitrogen at planting time to encourage seedling establishment.
A mixture of two or more compatible forage species provides diversity in wildlife plantings. Within mixtures forage species may be utilized that can complement one another. For example, One species may be tolerant of drought conditions, while another may be more resistant to browsing pressure. Mixtures should be intelligently formulated to provide full benefits of their individual species. Any of the four aforementioned warm season annual legumes can be planted individually or in any combination if seeding rates are adjusted proportionally.
One mixture which has proven successful in most soil regions of Mississippi contains two of these warm season annual legumes - iron clay cowpeas and American jointvetch. To establish this mixture, the following seeding rates are recommended:
- Iron Clay Cowpeas: 40 - 60 lbs./acre broadcast.
- American jointvetch: 10 - 15 lbs./acre broadcast.
The seeds in this mixture should be inoculated and planted at the same time, but separately, around May 1. The cowpeas should be planted first and covered about one inch deep, followed by the jointvetch, covered to about 1 inch. This can be easily accomplished by first planting and lightly covering the cowpeas by harrowing, followed by planting and lightly covering the jointvetch. The double harrowing of the cowpeas results in a greater planting depth than the single harrowing of the jointvetch.
Another recommended mixture that can sometimes be used effectively in high deer density areas is Alyce clover and jointvetch. To establish this mixture, the following seeding rates are recommended:
- Alyce clover: 10 lbs./acre broadcast.
- American jointvetch: 10 lbs./acre broadcast.
The seeds in this mixture should be inoculated, mixed, and planted at the same time, normally during May. Seeds should be covered to about 1 inch.
Seedbed preparation should begin with thorough disking of the selected site. The plot should then be harrowed to achieve a uniform planting surface. After seed distribution, do not disk-in seeds, but cover the broadcast seed by lightly harrowing. A culti-packer can be used at this point to help preserve existing soil moisture and to insure seed/ soil contact. Covering seeds by disking causes the planting depth to be highly variable and too deep, a common cause of failure in plantings.
Proper inoculation of legumes will increase forage production and ultimately reduce fertilizer cost by fixing nitrogen in the soil. Therefore, when establishing forage legumes, it is critical that seeds be inoculated with the required Rhizobium bacteria for the forage species used. For example, the same specialized Rhizobium inoculant can be used for Alyce clover, jointvetch, and cowpeas, but a different one is needed for soybeans.
Legume seeds are inoculated by applying live bacteria to the seed with a sticking agent. Sticking agents serve a dual purpose by adhering the inoculant to the seed and by feeding the bacteria until the seed germinates. Although commercial sticking agents are available, a 10% sugar solution or a soft drink works well. Seed should be lightly moistened with the sticking agent prior to applying the inoculant. Apply and mix the inoculant well to insure all seeds are covered . Allow the seed to air dry in order to ensure even distribution from a seeder. However, inoculated seed should be planted within 24 hours to retain viable bacteria.
Several precautions are in order when planting forage legumes. Rhizobia bacteria are very susceptible to heat and all inoculants should be stored in a refrigerator until ready for use. Inoculated seed should only be planted when soil contains sufficient moisture. Although the seed might survive if planted on dry soil, most of the bacteria will die before the seed germinates, resulting in poor forage production. Some varieties of forage species can be purchased pre-inoculated. Pre-inoculated seeds generally have a lime coating that not only protects the bacteria, but also adheres them to the seed. However, the bacteria will not remain alive for extended periods of time. Fresh seed should be purchased and stored in a cool location until planted.
The use of exclosures is an easy and inexpensive method of determining the amount of production and utilization in your food plot. They are easily constructed out of suitable fencing material, such as 1x4 or 2x4 wire. Light gauge wire (such as chicken wire) is generally not sturdy enough to withstand adverse weather conditions and contact from foraging deer. The exclosures should be about 3 feet in diameter and 4 feet in height. As a general rule, locate one exclosure for every acre of food plot.