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In many parts of the state, soybean fields are planted and ready to start growing. I can sense the genetic potential of the 2021 soybean crop. A soybean plant actively absorbs nutrients and moisture as it grows and develops new plant parts that advance through its vegetative and reproductive growth stages.

As the plant undergoes photosynthesis, develops nodules, develops new root zones, and other activities, it utilizes nutrients. These nutrients are referred to as essential nutrients, because without them a soybean plant cannot grow and develop as needed. When a plant needs more ‘supplies’ (nutrients) and the soil is unable to supply them, the plant will express a nutrient deficiency (stunted plant parts or discolored leaves). Generally, when we see these issues, it’s too late – the internal damage has been done.

Tissue sampling has been re-introduced to many producers as a way to be more proactive with plant nutrition, to monitor and detect yield-limiting nutrients prior to us actually knowing. Over the past six years, I have worked with many producers on tissue sampling projects for corn to monitor nutrients all season long and to set nutrient goals to maximize yields. This project has allowed me to better understand plant and soil nutrition and has also challenged many producers on how they manage fertility. Now is the time to take this concept from a corn field to a soybean field. 

I personally send all my plant and soil samples to Midwest Laboratories in Omaha Nebraska, please follow this link to view their Plant Tissue Sampling & Analysis pocketbook, which contains information and recommendations on how to best utilize plant tissue analysis.

Below are some items to consider or keep in mind as you challenge yourself for higher soybean yields and more efficient inputs. 

What a Tissue Sample Can Do:

• It does provide insight as to whether or not there is a nutrient deficiency
• It does point to which nutrient is deficient
• It does allow a producer to start asking questions on “why”
• It does allow a producer the opportunity to learn more about a plant’s season long needs
• It does allow a producer the opportunity to consider thinking about soil fertility differently
• It does provide a producer a license to learn!

What a Tissue Sample Can NOT Do:

• It doesn’t tell if a producer should go make an application later this week
• It doesn’t tell a producer the rate of a given product that should be applied
• It doesn’t tell a producer why a nutrient is deficient
• It doesn’t mean that a producer should go find a foliar product and make a reactive application

1. Like any data driven process, data out is only as good as data in:

a. Make sure to take samples of plants that truly represent the area. Don’t collect samples from plants that standout such as small runts or oddly large plants.

b. Make sure the sample location is a good representation of the area. Don’t collect samples from a wet spot, the peak of a knob, or a spot that’s known to have a scold.

2. Repeatability

a. Make sure to set a GPS pin of the location area for each sampling location so that you can come back several more times throughout the growing season. One tissue sample is like any other sample that’s looked at – the data is useless unless you collect a series of samples over the course of the season to monitor trends. Trends can provide actionable value, but one sample from one day of one growing season, just really doesn’t give us much to go off of. 

3. Clean samples:

a. When collecting plant tissue samples, it’s important not to collect them directly after a product application has been made. If there are nutrients on the outer side of the leaf that haven’t been absorbed or won’t be absorbed into the leaf, these elements will still show up in the tissue sample, which may give a false indication.

4. The sample:

• Since the tissue sample is comprised of H2O, the plants need adequate time and location to dry. Do not store these items in water, in a refrigerator or in a magazine. For best results, contact the receiving labs and order special bags.
• On the sample bags make sure to note all of the important information
  • Customer Name
  • Field ID
  • Sample ID

Additional Resources:

Plant Analysis - Nutrient Management | Mosaic Crop Nutrition