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The Clorox® Soak Test

Written by Brent Turnipseed, Assistant Department Head and Professor.

This test is used in the field to determine the percentage of soybean (Glycine max) seed damage due to combining or threshing. It is also adaptable to use in the laboratory. The test can be used for beans (Phaseolus vulgaris) and other large dicotyledonous seeds which may be injured in combining, threshing, or seed cleaning.

Materials Needed

  • Two or more small trays, plastic is preferable, large enough to hold 100 or more seeded are needed.
  • Clorox® (household bleach, 5.25% sodium hypochlorite) and ordinary tap water are used.

Procedure

1. Mix approximately three fluid ounces (3/16 of a pint) of Clorox® in one gallon of water. In the laboratory where only small quantities may be needed, a three to five percent solution of Clorox® in water may be used.

A manila envelope next to a yellow, plastic tray containing 100 soybean seeds.

2. Count out one or more replicated (depending on the accuracy desired) 100 seed sets excluding “splits” or obviously broken seeds. Place each of the 100 seed replicates in a tray or ice cream bucket.

A pair of hands carefully pouring a Clorox® solution from a brown, glass bottle into a yellow plastic tray containing soybean seeds.

3. Pour a sufficient amount of the Clorox®-water solution over the seed so it covers all the seeds.

A hand gently shaking a yellow, plastic tray containing soybean seeds soaking in a  Clorox® solution.

4. Gently shake the tray to cover the seeds with the solution.

Soybean seeds soaking in a Clorox® solution. Red arrows indicate several damaged seeds that have begun rapidly swelling.

5. After a few minutes you will see some seeds rapidly sweilling. These are the damaged seeds.

A group of soybean seeds drying on a paper towel. A small group of 13 damaged, swollen seeds is set aside from the pile.

6. After 10–15 minutes, pour off the Clorox®-water from each 100 seed replicate, then spread the seeds on toweling so they may be checked.

    7. Count the number of swollen seeds in each 100 seed replicate. If more than one replicate is included, average the number of swollen seeds in all of the replicates.

    Conclusion

    In the field it is generally considered that if there is over 10 percent swollen seed, seed damage is excessive. This degree of damage indicates that an adjustment should be made in the combine. In a cleaning plant the percentage of swollen seeds should be determined on a lot both before and after cleaning to determine the damage caused in cleaning.

    Notes

    • Avoid handling the Clorox®-water solution over varnished or painted surfaces.
    • If seeds are left in Clorox® solution more than 15 minutes, non-damaged seeds will begin to absorb the solution.
    • The Clorox®-water solution poured off the seeds may be reused but probably should not be saved more than a day.
    • Clorox® may be obtained from any supermarket.