ANR-18, Reprinted Jan 1998. Recommended for Extension use in Alabama by C. Dale Monks, Extension Crop Physiologist, Assistant Professor, and Dennis Delaney, Extension Associate, both in Agronomy and Soils at Auburn University. Previous revision by John B. Henderson, Extension Agronomist, Professor, Agronomy and Soils.

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Soybean Handbook for Alabama

The early history of cultivated soybeans, Glycine max (L.) Merrill, is unknown, but soybean culture apparently originated in North and Central China. The first written record of soybeans is contained in the books of a Chinese emperor who lived around 2838 B.C. The soybean is consistently mentioned in later records and was considered the most important cultivated legume and one of the five sacred grains of China essential for the existence of the Chinese civilization.

For centuries in the Orient, soybeans were grown mainly for the seeds. These were used in preparation of a large variety of fresh, fermented, and dried food products considered indispensable in the diet of Oriental people. Even today, soybeans remain the major source of protein for people in China, Korea, Japan, and other areas of the Orient.

The first mention of the soybean in American literature was in 1804. It is assumed that soybeans found their way to this country around the turn of the century. The early use of soybeans in the United States was primarily as a forage crop. They were used mainly for hay and silage in combination with corn for fattening hogs and sheep and, to some extent, for green manure. Soybeans were grown both alone and in combination with cowpeas, millet, and sorghum for hay. They were frequently grown with corn to supply nitrogen to the corn and enhance the quality of silage.

American grown soybeans were first processed for oil late in 1915 by a few cottonseed oil mills in North Carolina. The first mill known to extract soybean oil from American grown soybeans was at Elizabeth City, N.C. Early production in the United States was in the eastern and southern states. The five leading states in 1919 were North Carolina, Virginia, Mississippi, Kentucky, and Alabama. Acreage expanded into the Midwest around 1924, and this region is now the largest soybean-producing area in the country. lllinois is the largest soybean-producing state.

Prior to the late 1930s, most soybeans in Alabama were grown for hay and for soil improvement. By 1940, about 11,000 acres were being produced for oil, principally in Baldwin, Jackson, and Talladega counties. Soybean acreage in Alabama began to expand rapidly in the early 1960s. Harvested acreage increased from 135,000 acres in 1960 to a peak of 2,150,000 acres in 1979. Acreage has decreased since 1979, with only 295,000 acres harvested in 1993. The crop is grown to some extent in almost all counties, but the Tennessee Valley area in the north and the extreme southern counties of Baldwin, Mobile, and Escambia represent the major areas.

The United States leads the world in the production of soybeans. Other major soybean-producing countries include Brazil, China, and Argentina. Each year foreign markets take about 50 percent of the total soybean production of the United States. In Alabama, about one-half of the annual production moves through export markets, either as whole beans, meal, or oil. Prices Alabama growers receive for their soybeans are quite sensitive to both world economic developments and world production of soybeans.

The value of the soybean comes from its two primary raw products soybean oil and meal. A bushel of soybeans weighs 60 pounds and yields about 11 pounds of oil and 47 pounds of meal. Approximately 97 percent of the oil is used for human food products such as cooking oil, margarine, shortening, and salad oil. The remainder is used in industrial products such as paints, resins, and plastics. Soybean meal is used primarily as a source of protein for livestock and poultry. A small volume of soybeans is used in processed foods for human consumption.

Adaptation

Soil Selection. Soybeans can be produced on a wide range of soil types and under varying climatic conditions. Best yields are on deep, well-drained loams and sandy loams with good water-holding capacity and a high level of fertility. Soybeans should not be planted on extremely acid soils, deep sands, or eroded clays. They usually grow well on soils suitable for good corn production.

Rotation. Gradual decreases in yield have usually occurred where soybeans follow soybeans year after year, even though a high soil fertility level is maintained. Usually this can be traced to the buildup of disease and nematode problems, the development of a hardpan which restricts root growth, or a severe weed problem. A sound rotation program is necessary for profitable soybean production in Alabama.

Rotation with any other commonly grown row crops in the state is better than no rotation at all. Grain crops, such as grain sorghum and corn, are the best. Cotton can serve as a rotation crop, but careful monitoring of nematodes is advised. Winter crops such as small grains should not be considered for rotation because these do not serve to break the cycle of nematode development.

Land Preparation

Conventional. Several methods of land preparation can be used satisfactorily, including flat breaking with moldboard plow, chiseling, or heavy disking. The method chosen depends on the particular soil and situation, but the end result should be a weed-free, firm, and moderately smooth seedbed in which seed can be planted in contact with moist soil. A good seedbed is important for fast emergence, uniform stands, and rapid growth of seedlings. Whatever method is employed, excessive working of the soil] should be avoided in order to reduce compaction problems.

Deep turning with a moldboard plow is probably desirable on new land coming into row crop production, land having a heavy buildup of crop residue, or land in continuous soybeans that has not been turned for at least the past 3 years.

Chiseling or deep disking can give a good seedbed if a heavy residue is not present. Make sure that the chisels are running at a depth of at least 8 to 12 inches and that the soil is pliable. Where a hardpan is suspected, use subsoiling to break the pan. A hardpan can develop on any soil, but in Alabama it is normally not a severe problem except on sandy soils of the coastal plains.

No-Tillage. Many Alabama growers plant soybeans in unprepared seedbeds with little soil disturbance. This method does have advantages such as conserving soil moisture, reducing erosion, reducing labor requirements, and possibly reducing production costs. It also has some disadvantages, including higher herbicide costs and need for special equipment.

The most common no-tillage practice is to plant into the stubble of wheat or some other small grain following harvest or following the grazing down of the grain crop. The idea is that the stubble or residue from the grain crop will help conserve moisture, shade out weeds, and reduce erosion. Planting into old row crop residue or old unimproved pastures that have little sod growth defeats the basic purpose and is usually not successful. Planting no-till into a bahiagrass sod or some other perennial crop should be avoided because of the severe crop competition.

Weed control is probably the most difficult problem in no-tillage operations, but current herbicides properly used can ensure success. A contact herbicide must be used to kid the existing vegetation at planting, and a residual herbicide or some combination of residual herbicides must also be applied at planting. Do not plant no-tillage in fields infested with perennial weeds such as johnsongrass, bermudagrass, and nutsedge.

Soybean seeds should be covered with about 1 inch of soil to prevent injury from the herbicides. Planting in a depressed furrow should be avoided since heavy rains may concentrate herbicides in these depressions and cause crop injury or stand reduction. It is very important that the herbicides be applied in enough water to wet existing vegetation thoroughly. Read herbicide labels carefully before using, and observe all safety precautions.

Varieties for no-till should be carefully chosen from those recommended for the specific area. Best varieties are those that grow off fast and that will obtain sufficient height for good yields. This usually means mid- to late-season varieties. Factors such as planting date, soil conditions, row spacing, and weed problems should be considered when choosing a variety.

Narrow rows, 30 inches or less, are preferable for no-till planting. Modern no-till drills can be used if good weed control practices and proper seeding rates are followed. Increase the seeding rate by 10 to 15 percent over conventional planting to help insure a good stand. Place seed 1 to 1-1/4 inches deep, depending on sod and moisture conditions, and firm the soil around the seed.

Many factors are involved in no-till soybeans. Management is the key to success. Growers who anticipate trying the no-till approach should begin with a small acreage to become familiar with the method. County Extension offices have current information specifically on no-tillage soybeans.

Minimum Tillage. This term usually means that more land preparation or soil disturbance is done than in the no-tillage practice but less is done than in conventional planting. A technique which falls into this category is stale seedbed planting. This involves breaking the soil well ahead of planting, often in the fall; possibly disking once or twice in the early spring; then planting into the settled seedbed without additional disturbance. This helps conserve moisture and provides good conditions for seed germination. The use of no-tillage equipment is preferred for this type planting, although conventional equipment can be adapted. As with no-tillage, the use of a contact herbicide is often desirable if heavy weed growth occurs before planting. This method can enable earlier planting and a faster growing off time.

Double Cropping. Double cropping refers to the production of two successive crops on the same field during 1 year. In the case of soybeans, it usually refers to a small grain crop followed by the soybean crop. This is a common practice, particularly in the southern area of the state.

The economic considerations of double cropping depend on a grower's particular operation and the relative price of the two crops. Yields for double-cropped beans vary from year to year, depending on lateness of planting, weather conditions, and other factors. In southern areas where small grain is harvested at the normal time and late-maturing soybean varieties can be used, yields have generally been equal to full-season beans. In North Alabama it is more difficult to maintain yields comparable to those of full-season beans. However, if income from the grain crop can more than offset the reduction in yield of beans and if the grower is set up to handle small grain, then it probably is a profitable practice. A decision on double cropping should be an annual affair with the grower taking a look at market price predictions for both commodities. Double cropping is a viable option for Alabama growers and usually increases their chances for profits.

As with other practices, management is the key to success with double cropping. The small grain needs to be harvested as soon as possible so that soybeans can be planted in time to give them a sufficient growing period. One of the major problems is the lack of good moisture conditions at the time soybeans are planted. Planting should be geared to conserve moisture as much as possible. The use of no-tillage equipment has helped in conserving moisture at planting. Where small grain straw is burned or shredded and the soil disked, planting should follow immediately before the soil becomes too dry.

Choose soybean varieties for double cropping based on date of planting, soil type, disease and nematode problems, and harvesting capability. Early-maturing varieties have been grown successfully in the Tennessee Valley area. Later-maturing varieties usually have a better chance for success in most areas of the state.

Liming and Fertilization

Lime. Soybeans are quite sensitive to high soil acidity, and maximum yields cannot be expected unless the pH is at a favorable level. There is no specific pH value at which soybeans grow best on all soils. A pH between 5.8 and 6.5 is optimum to ensure that soil acidity is not a limiting factor. The Auburn University Soil Testing Laboratory currently recommends lime when soil] pH tests below 5.8, except on heavy clay or clay loams where lime is recommended below pH 5.6.

Soil samples should be taken for pH measurement and lime requirements at least every 3 years and preferably more often. It is very important to use only finely ground lime and to mix it thoroughly into the soil as far in advance of planting as possible. When flat-breaking is practiced, turn the soil first; then apply lime and mix with a disk harrow or similar equipment. Calcitic and dolomitic lime are both equally effective for correcting soil acidity.

Fertilizer. Soybeans respond best to a high level of fertility. Build soil up to a high fertility level by soil testing and by applying lime and fertilizer as recommended. Soybeans on soils with a high fertility level or those planted as a second crop after well-fertilized small grains may not respond to additional fertilizer. Do not omit fertilizer, however, except as recommended by a soil test.

The method of fertilizer application does not seem to be extremely important as long as the fertilizer is not placed too close to the soybean seed. It is suggested, however, that fertilizer be broadcast. One exception would be where beans are planted on a soil extremely low in fertility. When fertilizer is applied in the drill, it should be placed at least 2 inches to the side and 2 inches below the seed. If beans will follow small grain, apply all the fertilizer for both crops on the small grain.

Research has shown no increase in yield from applications of nitrogen fertilizer if soybean roots are well nodulated. The soybean plant can obtain its own nitrogen through bacteria that form nodules on its roots. A small amount of nitrogen, about 20 pounds per acre, might help when beans are planted for the first time on unimproved pasture land or newly cleared land. A small application may also be of value on late-planted beans behind small grain if a large amount of residue is worked into the soil.

Most Alabama soils on which soybeans are grown have an adequate supply of micronutrients. The availability of these micronutrients to plants is influenced by the soil pH. Growers who lime on a regular basis and maintain their soil pH in the range of 5.8 to 6.5 should experience no problem with micronutrient deficiency. Exceptions might be manganese deficiency on certain unique soils, iron deficiency on extremely high pH soils, and molybdenum deficiency on low pH soils.

The micronutrient molybdenum is required in extremely small amounts for plant growth and for the normal functioning of nitrogen-fixing bacteria. As the soil pH decreases, molybdenum becomes less available to plants. On soils where lime is recommended but not applied or where a soil test is not made, an application of molybdenum is advisable. Molybdenum is commercially available in small packages for application to the soybean seed at planting. As always, follow directions on the label.

Varieties

Soybean varieties are currently divided into ten groups according to their maturity. Group 00, the earliest-maturing group, is adapted to the short-season conditions of the extreme northern states. Succeeding groups are adapted further south, with Group VIII varieties suited to the longer growing season of the extreme southern part of the United States.

Soybean plants begin flowering and fruiting primarily in response to day length. Each variety responds to a critical period of darkness to change from the vegetative to the flowering stage. An early-maturing variety is sensitive to a shorter night and, therefore, requires fewer hours of darkness to initiate flowering. A late-maturing variety requires more hours of darkness to initiate flowering. It matures later in the season, allowing a longer period of vegetative growth, and is better suited for later plantings.

Flowering begins according to one of two growth habits: determinant or indeterminant. Determinant growth means that plants grow vegetatively until a critical day length triggers flowering, at which time vegetative growth essentially stops. Plants having indeterminant growth continue some vegetative growth during the flowering period.

Most soybean varieties grown in Alabama have a determinant growth habit, as opposed to the indeterminant growth habit of varieties grown in the Midwest. Public and private breeding programs have released some early-maturing varieties that carry some degree of indeterminant growth habit. These varieties in Group IV are being planted by some Alabama growers.

Groups V, VI, VII, and VIII are well adapted for Alabama conditions. The very early-maturing varieties of Group V are recommended for the northern and central part of the state. The very late-maturing varieties of Group VIII are recommended for only the central and southern areas.

In addition to maturity dates, soybean varieties differ in their growth habits, plant height, and resistance to lodging, shattering, and pests. Select the recommended variety best adapted for your growing area and farming situation.

On a long term basis, very early-maturing varieties usually yield less than later-maturing or full-season varieties. However, early varieties may outyield full-season varieties in some years because of rainfall patterns and other weather conditions especially in northern areas. It is best to plant more than one variety in order to spread weather risks and to stagger the harvesting period.

Variety tests are conducted each year to determine which varieties perform best in Alabama. New varieties are continually being developed and evaluated. Auburn University has a full-time plant breeder developing varieties specifically for Alabama conditions. County Extension offices will have current variety test results, information on characteristics of commonly grown varieties, and a list of recommended varieties for different areas of the state.

Planting

Planting Date. Planting on time is necessary in order to obtain sufficient plant height before the onset of flowering. Most growth stops when plants begin to flower, so a delay in planting often results in short plants and reduced yield. Planting too early before day length reaches an optimum for vegetative growth also results in short plants. Planting an early-maturing variety too late can cause pods to set too low on the stalk. Planting a late-maturing variety too early can cause excessive plant height and increased lodging.

Recommended planting dates vary within the state because of differences in clay length. Planting dates for specific areas are developed based on observations made over many years. There is great diversity between varieties so that slight variation in the planting may not be significant in a particular year. But research has shown that planting within these dates increases the chances that the potential yield of a variety will be realized.

Plant from April 25 through June 10 in northern areas, May 1 through June 20 in central areas, and May 10 through June 25 in southern areas. Begin planting within the recommended period just as soon as the soil moisture is adequate for quick germination. When conditions make it necessary to plant earlier or later than the recommended period, variety selection becomes more critical. Check with your county Extension office for suggestions.

Row Width. Research in Alabama and other states in the Southeast has not shown consistent yield differences when row spacings vary from 18 to 36 inches, provided plantings are made within the recommended planting period and all good practices are followed. However, when beans are planted later than the recommended period, there is a significant yield increase for narrow rows. Rows must be narrow enough for soybean plants to form a closed canopy by the time flowering begins. Although no consistent yield increase has been noted from narrow rows when beans are planted within the recommended period, there has been no decrease in yield from narrow rows as long as appropriate seeding rates and good weed control are observed. With changing varieties, double cropping, and better herbicides for weed control, most Alabama growers would benefit by moving to 30-inch rows or less.

Seeding Rate. Seeding rates for soybeans vary, depending on seed size and germination. Varieties may range from as many as 300,000 seeds per bushel for very small-seeded varieties to as low as 150,000 for the larger-seeded varieties.

Seeding rates should be based on number of plants desired per foot of row rather than pounds of seed per acre. For 36- to 40-inch row widths, adjust planters to put about ten seed per foot; for 30 to 36 inches put about eight seed per foot. This will probably require about 35 to 55 pounds of seed per acre, depending on seed size. For narrower rows, adjust planters to put fewer seed per foot of row so that about the same seeding rate per acre is maintained. Where poor quality seed must be used or planting is done under unfavorable conditions for germination, the seeding rate should be increased.

Planting Methods. Both drilling and broadcasting soybeans are acceptable under certain conditions. Planting with some type of grain drill seems to give more uniform planting and more bean growth than broadcasting. The problem of controlling weeds is a major consideration in drilling soybeans, and growers should be selective in determining areas for this practice. Drilling can be a good practice if growers can successfully control weeds and have a drill heavy enough to place and cover seed uniformly.

Planting methods influence row width and seeding rate. For drilled beans in 7-inch spacings, place two to three seed per foot of row. For average-size seed, this will probably require about 45 to 65 pounds per acre, but amounts will vary with the size of the seed. For wider drill spacings, increase the number of seed per foot, but maintain about the same amount of seed per acre. For broadcasting, use 60 to 70 pounds per acre depending on the size of the seed and the percent of germination. There is a tendency to get plants too thick when drilling or broadcasting, creating greater lodging problems.

Depth of Planting. Planting soybeans at the proper depth is necessary so that plants can emerge rapidly. How fast seedlings emerge after planting is one of the most important factors affecting the early development and growth of soybeans. Young plants that emerge rapidly seem to develop better and grow off faster. Because soybean seedlings tend to be weak in their ability to push out of the soil, plant seed only 1 to 1-1/2 inches deep.

Germination. Plant soybeans only when moisture is adequate for good germination. Soybean seed must absorb about 50 percent moisture by weight in order to germinate. When sufficient moisture is not present, seed may swell but not germinate and emerge, resulting in poor stands and weak plants. Delay planting until sufficient moisture is available for seed germination.

Always buy high-quality seed having 80 percent germination or better. Seed grown and stored on the farm should be satisfactory if they are cleaned well and have good germination. The State Seed Laboratory will make germination tests upon request. Most growers do not have the facilities to adequately store seed beans and maintain quality. Purchasing certified seed usually pays dividends.

Inoculation. The soybean is a legume and will extract nitrogen from the air through the association of bacteria which form nodules on the soybean roots. If these bacteria are not present in the soil, they must be added through the process of inoculation. This involves coating soybean seed with a mixture of appropriate bacteria. An inoculant should be added to soybean seed planted on new land or on land that has not been in soybeans for the past 3 years. Where a well-nodulated crop of soybeans has been grown within the past 3 years, the addition of an inoculant would probably not be necessary. If there is any question as to whether or not the soil contains sufficient nodulating bacteria, be sure to inoculate. Use a good peat-base inoculant specifically prepared for soybeans. Bacteria prepared for other legumes are not effective on soybeans. Keep inoculant in a cool, dry place, and blend with seed at planting according to directions on the label.

Soybean inoculants are living organisms, and research has shown that premixing a seed treatment (fungicide) or molybdenum (micronutrient) with the inoculant ahead of planting may reduce its effectiveness. Application of these materials with the seed in the hopper box immediately ahead of the actual planting operation may cause some injury to the inoculant. However, in most cases this process appears to work satisfactorily When seed quality is poor and a fungicide is advised, treat with the fungicide first and then inoculate just prior to planting. On land going into soybeans for the first time, it is best to use only inoculant and not to apply a fungicide or molybdenum.

Weed Control

Weed problems in soybeans might be classified as perennial grasses such as johnsongrass, annual grasses such as crabgrass, small-seeded broadleaf weeds such as pigweed, and large-seeded broadleaf weeds such as sicklepod. Annual grasses and small-seeded broadleaves can be rather easily controlled with preplant and preemergence herbicides.

Perennial grasses and large-seeded broadleaves, including cocklebur, sicklepod, and morning glory, require more management. With proper application and optimum moisture and weather conditions, herbicides can control these. But under less-than-optimum conditions, preplant and preemergence herbicides often fail to give consistent control of large broadleaf weeds. Growers need to be prepared to use post-emergence or post-directed herbicides. The application of post-directed sprays when weeds are small offers an effective and economical approach. Using post directed equipment makes a grower flexible enough to use several weed control alternatives. No single herbicide will control all weeds. However, a preplant or preemergence herbicide followed by postemergence applications and mechanical cultivations can yield clean beans. Timeliness and proper application is the key to success.

A good arsenal of herbicides exists for use on soybeans, and new ones are continually being developed. A list of recommended herbicides is not included here because the list changes from year to year. Your county Extension office will have a list and complete information on use of herbicides for soybeans.

The following steps are necessary for a successful weed control program on soybeans:

• Know your weed problem. Any program must be geared toward controlling the major weed problems. Planning an effective herbicide program is impossible unless the specific weed problem is known. Problems vary from field to field, and a different program may be required for each field. A weed map of different fields is a very helpful tool.
• Select the right herbicide. Most herbicides used in soybeans are quite selective. They may give very good control of one weed and have essentially no effect on another. Determine the major weed problem and select herbicides which have been shown most effective on that specific problem.
• Apply herbicides at correct rates. Rates of herbicides necessary for effective control vary with soil types, size of weeds, size of soybeans, conditions at application, and other factors. Follow closely the recommendations on rates for the specific conditions. The various soybean herbicides are applied either as preplant (prior to planting), preemergence (after planting but prior to emergence of soybeans), or post-emergence (after beans have emerged). Postemergence may involve over-the-top or post-directed sprays. How a herbicide is applied depends on the nature of the herbicide and the various conditions. A herbicide must be applied properly if it is to have the desired effect.
• Recognize limitations of herbicides. The performance of herbicides depends on temperature, moisture, and other climatic conditions. Most preemergence herbicides, for example, depend on moisture in the form of either rain or irrigation to activate them. If moisture is not received within a certain period, these herbicides become less effective. Be aware that factors may develop which cause herbicides to perform poorly, and be prepared to use an alternative weed control method.
• Use mechanical control. Successful weed control generally requires a combination of chemical and mechanical control methods. Use sweeps or a rolling cultivator frequently enough to control small weeds. Set sweeps to run flat and shallow. Deep cultivations can bring up untreated soil and prune soybean roots. Do not throw soil around the base of plants during cultivation. This could increase disease problems and interfere with harvesting operation. Soybeans planted in moist soil should be up in 3 to 5 days, should have the drill shaded in about 3 weeks, and should have a complete ground cover in about 6 to 7 weeks under good growing conditions. Growers relying strictly on cultivations must complete operations by the time beans are about 6 to 8 weeks old.
• Use good production practices. Other production practices have a tremendous influence on a weed control program. Planting soybeans on time and under conditions favorable for rapid emergence makes weed control easier. Proper liming and fertilization make for better growth of soybeans and improve the chances for controlling weeds. Variety selection, crop rotation, uniform stands, pest control, and row spacing all influence weed control.

Insects

Soybean insects are a major production problem in Alabama. The severity of the problem varies, but each year some growers experience losses from the various insect pests. Fortunately, soybeans can tolerate considerable foliage loss at certain growth periods without loss in yield. Research has shown that prior to flowering, soybeans can tolerate a foliage loss of up to 35 percent if growing conditions are favorable. After flowering, yield can be reduced if more than 20 percent of the foliage is lost.

To estimate amount of foliage loss, pull several plants from different areas of the field, hold them toward the sky, and examine all the leaves. Most foliage-feeding insects prefer the new succulent growth in the top of plants. This causes a ragged appearance in the tops. Fields may appear to have more damage than actually exists, so pull up and observe plants to determine the amount of foliage loss.

Soybean insects are generally grouped, for convenience, into stem feeders (those that attack the young seedlings), foliage feeders (those that feed primarily on the leaves), and pod feeders (those that principally damage the pods). Some insects can fit in more than one of these groups. The podworm (corn earworm), for example, is both a foliage feeder and pod feeder although it is considered to be most destructive as a pod feeder.

The selection of an insecticide and the rate and method of application should be based on the specific insect or insects in a field. Fields should be checked at regular intervals to determine which insects are doing the damage.

Insects are identified by their physical characteristics. The more important species of worms that attack soybeans can be identified by the number of legs near the center of the body, known as the prolegs (Figure 1). Worms that have the same number of prolegs are identified by other characteristics. The podworm and velvetbean caterpillar, for example, both have four pairs of prolegs, but the podworm curls up when shaken off the plant while the velvetbean caterpillar bounces around vigorously. Most insects also have different color markings that help separate them.

Be sure of the insect problem and its severity before beginning a control program. Applying an insecticide before it is needed not only costs money but can create greater problems later by killing beneficial insects.

To check for insects, spread a shake cloth or white sheet of paper between two rows of soybeans. Kneel and encircle the foliage of both rows with your arms (about 3 feet of row), and shake it vigorously to throw the insects onto the cloth or paper. Then check quickly to determine the kind, size, and number of insects present. Repeat the procedure at random locations to get an average for the entire field. Check fields at least once a week and more often during periods when insect populations are building up rapidly.

Changes in insecticide recommendations may be necessary from time to time because of the development of new or improved insecticides, methods, and techniques of application and changes in labeling by regulatory agencies. Your county Extension office will have current insecticide recommendations for local soybean insect problems. They will also have descriptions of insects, suggested methods for surveying fields, and all the current insecticide information.

Diseases and Nematodes

Diseases. Various diseases attack seedlings, foliage, and roots of soybeans. These diseases are caused by fungi, bacteria, viruses, and nematodes. Damage varies from year to year, depending on the particular diseases present and the occurrence of weather conditions favorable for their development. Most diseases develop more rapidly when the temperature is warm and when rain, fog, or heavy dew cause humid conditions. This is especially true with leaf, stem, and pod diseases.

Control of soybean diseases is based more on preventive measures than on chemical treatments. There are, however, certain fungicides recommended under specific conditions for treating poor quality seed and for controlling the complex of foliage, stem, and pod diseases.

The following practices, when used in conjunction with other sound production practices, can help keep soybean diseases to a minimum.

• Use resistant varieties. Most recommended varieties are resistant to certain diseases. The effectiveness of these varieties will depend on the kinds and severity of diseases present.
• Rotate soybeans. A good system in which soybeans are rotated with grain crops or other non-host crops can reduce diseases.
• Turn soil deep. Many disease organisms overwinter on old soybean residue. Turning this material deep in the soil can prevent many organisms from surviving and infecting new plants the next season.
• Use good quality seed. This is very effective in reducing seed rot and seedling diseases which can result in poor stands and stunted growth.
• Use fungicides. When weather conditions are favorable for disease development, fungicide applications have often proven effective in improving soybean yields and seed quality.

Nematodes. There are several species of nematodes that attack soybeans. These small, microscopic worms feed on the roots of soybean plants and reduce their ability to obtain water and nutrients for normal growth. Only by taking a soil sample and having it analyzed can you know the kind and number of nematodes present.

When nematodes are limiting yield, some effort must be taken to control them. The following are some suggestions on ways to manage the nematode threat:

• Rotate crops. Nematodes build up to extremely high levels in soils, especially where soybeans have been grown continuously in the same field or in rotation with vegetables, peanuts, cotton, and other susceptible crops. Rotate with corn, grain sorghum, small grain, or some other non-leguminous crop. Usually a 2- to 3-year rotation is necessary to reduce nematode populations to a manageable level. Then a regular system of crop rotation should keep populations at a manageable level.
• Use resistant varieties. Breeders are continually developing varieties with resistance to one or more species of nematodes. While this has met with some success, the number of nematode species which attack soybeans, as well as the ability of certain ones to form new pathogenic races, has made it difficult to depend on this as the only control method. But the selection of varieties is critical and deserves special consideration.
• Treat with nematicides. There are only a few nematicides available that give effective control of nematodes in soybeans. Nematicides in soybeans are not always economically feasible, and at present there is limited use in Alabama.

Soil tests are available to determine the type and number of nematodes in a field. The optimum time to sample for nematodes is during September, October, and November. Your county Extension office will have complete instructions on taking soil samples for nematode analysis as well as the current nematicide recommendations.

Harvesting

Think of harvesting when you plan your production program. Varieties, date of planting, and weed control can influence shattering, height of pod set, and time required for harvesting. Plant flat or on a slightly raised bed, and do not throw soil up around the base of plants when cultivating. Automatic height control devices, flexible floating cutter bars, and individual row crop headers will pay for themselves quickly.

Soybeans usually mature rapidly and uniformly. When the leaves have turned yellow and most of them have dropped, take a seed sample about every 3 days for moisture determination. Start harvesting when beans get down to 16 percent moisture. Soybeans usually dry rapidly in normal fall weather, so the moisture will be down to 13 percent in only a few days. Harvesting at high moisture content can reduce harvest losses. On-farm drying facilities make it feasible to start harvesting at moisture contents as high as 18 percent, unless threshing problems develop. Moisture below 12 percent will result in excessive shattering, splitting, and cracking.

Shattering at the cutter bar is normally the point of greatest harvest loss. Excessive ground speed, over 3 miles per hour, can be a major cause of high shatter loss. Shatter losses can be reduced by slowing ground speed and by operating the cutter bar just below the bottom pods.

Proper operation and adjustment of the combine can make the difference between a good job and a poor job of harvesting. Follow the operator's manual for cylinder and separation unit adjustment. An average of four beans per square foot on the ground means a loss of a bushel per acre. An easy and fast method of determining harvest loss is available from your county Extension office.

Drying and Storage

Alabama soybean growers use on-farm storage and drying facilities as well as commercial facilities, and there are advantages to both. The main advantages of on-farm storage and drying are: (1) the crop may be harvested earlier and at higher field moisture content, thus reducing the possibility of field losses from adverse weather conditions and shattering; and (2) an adequate storing and drying system will help both harvesting and marketing programs. By having storage facilities on the farm, the producer is assured a place for his crops during the rush harvest period. Commercial elevators and storage facilities often become overcrowded at this time, causing trucks, trailers, and other transportation equipment to be tied up while waiting to be unloaded. Stored beans can be marketed during the period when prices are normally higher instead of at harvest time.

There are some disadvantages of on-farm storage, including the initial expense and the annual cost involved in having such facilities. Additional management and labor are also required.

Alabama has a relatively large number of commercial storage facilities. There are certain advantages to commercial storage, such as: (1) less management requirements; (2) less labor; (3) no worry about the condition of beans; and (4) no investment in storage and handling equipment. But most growers find that on-the-farm storage offers them more flexibility.

When using on-farm storage, put soybeans in a drying bin immediately after harvesting, and dry them to a moisture content of 11 percent or less before placing in storage bins. Soybeans must be maintained at this moisture level if they are to be stored for long periods. When moisture content within stored beans exceeds 11 percent, spoiling and heating may occur.

After beans are dried and placed in storage bins, some means of aeration should be provided. Small volumes of air must be forced through the beans to cool them and to equalize temperatures within the bin.

The main purpose of aeration is to cool the beans. Operate aeration fans only when the outside air temperature is 15 or more degrees lower than the temperature of the soybeans or when the relative humidity is 60 percent or less. Your county Extension office can provide detailed information on storing and drying soybeans.

Marketing

Most Alabama soybeans are sold at harvest time. The rest of the crop is stored on the farm or in commercial elevators for later sale. Most soybeans go from the farm to county elevators; some go directly to processors or exporters. Alabama has a highly developed soybean marketing system. Most growers have ready access to a marketing outlet. Sound marketing is one of the producer's most important practices. Decisions about marketing often mean more than yields in determining a grower's net profit. Growers should carefully consider available marketing alternatives and seek assistance in making marketing decisions.

Crop prices fluctuate sharply from month to month and from year to year. Prices may vary considerably during the crop year. Therefore, timing sales correctly presents one of the best opportunities to increase profits.

The market structure for soybeans is such that you may price your crop any time from several months before planting until several months after harvest if you have storage. By following a well-thought-out marketing plan, you can remove much of the risk of fluctuating prices. Producers have three major choices or methods of selling: (1) sell at harvest; (2) store for later sale; and (3) forward price with a cash contract or futures hedge. Some combination of the three methods may be the most practical for many farmers. Detailed information on marketing alternatives is available at county Extension offices.

Soybeans are bought and sold on the basis of grade according to official grade standards of the United States. Soybeans of top quality are graded No. 1, and price quotations are usually given on the basis of No. 1 beans. Table 1 gives the official standards for soybeans as established by U SDA.

Table 1. United States Department of Agriculture Official Standards for Soybeans

Grade	Minimum Test Weight Per Bushel (lb.)	Maximum Limits Of
		Damaged Kernels					Brown, Black, or Bi-colored Soybeans In Yellow Or Green Soybeans (%)
		Moisture (%)	Splits (%)	Total (%)	Heat Damaged (%)	Foreign Material (%)
U.S. No. 1	56	13.0	10.0	2.0	0.2	1.0	1.0
U.S. No.2	54	14.0	20.0	3.0	0.5	2.0	2.0
U.S. No. 3(a)	52	16.0	30.0	5.0	1.0	3.0	5.0
U.S. No. 4(b)	49	18.0	40.0	8.0	3.0	5.0	10.0
U. S. Sample Grade: Sample grade shall be soybeans which do not meet the requirements for any of the grades from No. 1 to No. 4, inclusive; or which are musty, sour, or heating; or which have any commercially objectionable foreign odor; or which contain stones; or which are otherwise of distinctly low quality.
(a) Soybeans which are purple mottled or stained shall be graded no higher than No. 3. (b) Soybeans which are materially weathered shall be graded no higher than No. 4.

Soybean marketing firms maintain a schedule of discounts for soybeans. Factors for which substantial discounts are charged are moisture, kernel damage, and foreign material. Soybeans containing crotalaria seed can be rejected because of their toxicity to livestock, especially poultry, or discounted to cover the cost of special handling and cleaning.

Economics

Profitable soybean production requires good management, which means following a complete program of recommended practices and performing operations on time. Many Alabama growers have more acreage than they can efficiently manage with their present labor and equipment. Time spent on careful analysis of the overall operation and on detailed planning prior to the cropping season can bring large returns to a soybean producer.

Many factors influence production costs and profits from soybeans. Size and efficiency of the operation, price received for beans, and many other variables help determine profitability. Increasing the yield offers one of the most promising areas for more net profit. It costs little more to produce a 40-bushel soybean crop than it does to produce a 20-bushel crop. The most successful producers are usually those who consistently average relatively high yields.

County Extension offices have budget guides which give estimated costs and returns for soybeans under a given set of conditions and yield.

Production costs, conditions, and prices of beans vary within the state and from year to year, so these budgets can only serve as a guide. However, growers can take these guides, insert figures applicable to their operation, and calculate estimated cost and returns per acre.

World Markets

The United States is the world's largest soybean producer and exporter. Soybeans and soybean products are the leading U.S. agricultural export commodity, and dollars derived from soybeans are important to the U.S. balance of payments.

Japan is the largest single customer for whole beans. The countries of Western Europe represent the largest market for U.S. soybeans and soybean products going into foreign trade. Prices for soybeans are influenced greatly by the world market for protein meal, fats, and oil. Soybeans presently enjoy a market preference due to their high percentage of protein and oil, but they face heavy competition in the oil market from palm oil and other oilseed crops.