Soybean management practices

A producer can utilize a variety of different management practices to raise a soybean crop. Type of tillage, plant population, row spacing, and planting date are four major management decisions that soybean farmers over the world must consider. How individual producers choose to handle each management application depends on their own farming circumstances

Tillage

Tillage is defined as disturbing the soil in preparation for a crop. Tillage is usuallydone to warm the seed bed up, help dry the seed bed out, break up disease, and reduce early weed pressure. Tillage prior to planting adds cost per acre farmed and has not been shown to increase soybean yields significantly.

“No till” is the practice of planting seed directly into the ground without disturbing the soil prior to planting. This practice eliminates the tillage pass, saving the farmer its associated costs. Planting no-till places seed directly into a cooler/wetter seed bed which can slow down the germination of the seed [Hoeft 96] . This process is considered a good conservation practice since tilling disturbs the soil crust, causing erosion. The practice of no-till is currently on the rise among farmers in the midwestern United States.

Plant Population

15 inch rows125,000 to 140,000

30 inch rows125,000 to 140,000

Plant population is the number of seeds planted in a given area. This is usually expressed as plants or seeds per acre. Plant population is one of two major factors that determine canopy closure (this refers to when the plants cover the space in between the rows) and other yield components [Pedersen] . Higher seed populations will close the canopy faster and reduce soil moisture loss. But high plant populations do not mean high yields. The recommended seeding rate is 125,000 to 140,000 seeds per acre [Pedersen] . The ultimate goal is to achieve a final stand of 100,000 plants per acre [Pedersen] . Planting the extra seeds gives the producer added insurance that eachCourtesy of Iowa State Extensionacre will attain a final stand of 100,000 plants.

Row Spacing

Row spacing is the second factor that determines canopy closure and yield components [Pedersen] . Row spacing can either refer to the space between plants in the same row or the distance between two separate rows. Row spacing is important because it helps in determining plant to plant competition [Pedersen] . Rows planted closer together at a given population will increase the space between plants within the row. Likewise, the farther apart the row widths are at any given population, the less space there will be between plants within the row. Closer row widths decrease plant to plant competition for nutrients and water while increasing sunlight use efficiency. According to Iowa State University Soybean Extension [http://extension.agron.iastate.edu/soybean/] Specialist Palle Pedersen, current recommendations are to plant rows that are less than 30” apart. This increases light interception, increases plant spacing within rows, and decreases weed competition.

Planting Date

Planting date refers to the date that the seed is sown. This concept is of prime importance in growing soybeans because yields are strongly correlated with planting date. Data from Iowa State University shows that earlier planted soybeans tend to have higher yields than soybeans planted later in the growing season. Producers seeding early need to check that the seedbed is in the right conditions (temperature, moisture, nutrients) since planting into a sub-optimal seedbed will lose yield instead of gaining it [Pedersen] . Other special considerations include soil pathogens, insect pressure, and the possibility of frost. Fungicide treatment and insecticide treatment are options used to help reduce the risk of soil pathogens and insect pressure [Hoeft 89] . Knowing the chance of frost in a given area prior to planting will help determine how early seed can safely be sown [Pedersen] .

General Recommendations

Although these guidelines provide a solid starting point, producers should always check with local, state, and university agronomists when making a decision. These management practices form the base of successful soybean production, but many other management decisions apply as the crop matures. These are sound decisions that apply wherever soybeans are grown, but more specific practices may be applied depending upon the growing area. Soybean growers, breeders, and researchers are continually pushing the envelope, producing new genetic lines and new management practices to increase soybean yields across the globe. New management techniques will undoubtedly replace outdated management practices as research continues to unlock the key to higher soybean yields.

References

* Pedersen, Palle. "Soybean Production." Iowa State University Soybean Extension and Research Program. 4, January 2008. Iowa State University Extension. 20 Feb 2008 .
* Robert G. Hoeft, Emerson D. Nafziger, Richard R. Johnson, and Samuel R. Aldrich . Modern Corn and Soybean Production. '1st ed. Champaign, IL: MCSP Publications, 2000.