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What is an ideal soybean planting population?

Agronomy Bulletin 11 ─ Planting Population for Soybeans

The ideal population varies by variety type.

Situation

Soybean growers can maximize the yield potential of their crop by ensuring it is planted at an ideal population. Plant populations vary by geography, so it is important to consider local conditions as well as the variety, row width, seed treatments and other factors.

Factors to Consider

  • Variety of soybeans
  • Planter row width
  • Seed treatment use
  • Plants per acre
  • Planting date

Action Plan

  1. Select varieties appropriate for the environment. Soybean varieties vary on yield potential, disease tolerance as well as numerous other agronomic characteristics. Increased yield potential is but one of many key considerations when new varieties are released for commercial sale. Often, higher plant populations may not deliver an additional yield increase.
  2. Choose a row width appropriate for variety. Generally, drilled soybeans or those planted in narrow rows require higher plant populations than those planted in wider rows. Attention should be given to the growth habit of the selected variety: Is it a bushy or narrow canopy soybean? Understanding how the soybeans will be planted, including the planting depth, can help determine planting populations.
  3. Determine if seed treatment will be used. Seed treatments, especially fungicide-based treatments, have been shown to help improve emergence. Instead of relying on tighter plant spacing to aid in emergence, seed treatments can help the plants emerge more uniformly regardless of in-row spacing, allowing growers to consider reducing seeding rates
  4. Realize having fewer plants per acre isn't always better. Growers should evaluate the pros and cons of different population rates before making planting decisions. Many growers believe they can get higher yields by planting fewer soybean plants per acre. However, certain varieties can be planted too thin in the wrong environment. Higher populations produce a tighter canopy, which can enhance weed control, but also may increase disease pressure. Take these factors into consideration and understand the ideal population varies by variety type.
  5. Understand how planting date can impact populations. Because early planting may put more stress on seedlings than later planting, higher seeding rates can sometimes be considered. However, the planting date can be less critical to final yield potential when using seed treatments and higher-yielding genetics like those found in new and improved varieties.

Summary

Once you select the right variety for the yield environment, determine the appropriate planting population to maximize yield potential. The right population for each variety should be based on the plant type, row spacing, seed treatments, date of planting disease factors and prior experience with the variety. For more information, contact your local Mycogen Seeds commercial agronomist or trusted agronomic adviser.

Published on Monday, March 20, 2017