UACES Facebook Strawberry Plant Tissue Nutrient Program
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Arkansas Fruit, Vegetable and Nut Update

Strawberry Plant Tissue Nutrient Program

by Amanda McWhirt - March 8, 2018

How to participate in the strawberry plant tissue sampling program and results from last year's samples.

Basics of the Strawberry Nutirent Monitoring Program

Sampling the leaves and petioles (stems) of your strawberry plants during bloom, and sending them to be analyzed for basic nutrients is a good way to see if the plants have enough Nitrogen and other nutrients to produce a good crop. The test results will tell you if you need to amend your spring fertility program early in the season when there is still time to effect the crop being made. 

We have a program set up at the University of Arkansas to help strawberry growers sample their strawberry crop in the early spring and understand how to amend their fertility program accordingly

Here is information on the program and the sign up sheet

Be sure to read this thoroughly as there are tips on how to take the sample and when. You will need to separate petioles from the leaves. Contact your local county agent for help. 

Here is a guide to help growers interpret their test results.

 

Results from Last Year's Nutrient Sampling Period

Last year we collected data from all the samples growers submitted to the strawberry plant tissue testing program to see if growers were meeting current recommended ranges for plant tissue nutrient content at different stages of crop development.

Over twelve weeks in the spring of 2017 strawberry leaf tissue and petiole nutrient results submitted to the Arkansas Agricultural Diagnostic Laboratory in Fayetteville Arkansas were collected and analyzed.

Data Collected

One sample consisted of 15-20 leaves + petioles

  • Strawberry growth stage, variety, location and bloom stage for each sample
  • Chandler 87.5% of samples
  • Nutrients analyzed:
      • Leaf (N, P, S and B)- these nutrients analyzed from the leaf samples are used to understand stored nutrients and make changes to P, S or B fertilizer rates
      • Petiole (NO3-N)- The level of nitrate nitrogen (NO3-N) in the stems or petioles is used to amend Nitrogen fertilizer rates for the following week, it is a measure of Nitrogen actively being taken up by the plant. 

  • Locations

    15 growers across AR, 5 growers outside of AR

  • map of locations

                                                                  Data Analysis

  • 20 Growers submitted 136 samples
  • Scatterplots and averages of nutrient results were compared to recommended ranges (Campbell and Miner, 2000) for plant nutrient content based on data collected on phenological crop stage. Individual data points are not tracked to protect grower anonymity.

Results

The orange bars represent where the standard recommended range is for the season or the crop stage. 

For Leaf tissue Nutrients

Most nutrients were within the recommended ranges. Boron was the exception with several growers being too high or too low.

leaf graphs

Excessive boron can cause toxicity symptom like this:

boron toxicity burn on leaf edgestrawberry boron toxicity

Thanks to Karlee Pruitt for sharing these pictures of Boron toxicity!

 

Not enough Boron can result in misshapen fruit. This often appears as fruit that are poorly formed on one side or undersized.

Here is a picture from Cornell:

boron deficient strawberry

Picture Source: https://blogs.cornell.edu/berrytool/strawberries/strawberries-fruits-are-deformed-or-nubby-at-the-tips/

 

If your test comes back as low Boron? Apply a low rate of 0.125 lbs B/ acre to start. 

To get 0.125 lbs of B per acre you could apply:

  • 1 lb of Borax (11% B)
  • 0.5 lb of Solubor (20.5% B)

 

For Petiole NO3 

It is important to remember for petiole NO3-N the recommended range changes based on the crop age. In the early season during bloom the petiole NO3-N level should be between 4000 and 6000 ppm and should drop down to between 3000 and 5000 once fruiting starts. For this reason we ask what the crop stage is on the form when you submit a sample. 

Early in the season a large number of growers where below the recommended range for petiole NO3-N contents. This is significant because early in the season is when fertility rates are likely most important in determining the crop yield potential later in the season.

petiole avergaes over the season See the Area I am referring to highlighted here:

petiole avearges over season, highlight

Growers should quickly amend their fertility programs upon receiving a test result with low petiole NO3-N.  

Here is a guide to helping determine how much nitrogen to put out per acre based on your petiole NO3-N test results. Calcium Nitrate and Potassium Nitrate are commonly used in fertigation programs for plasticulture strawberry production in the spring. 

 fertility conversion chart

I will collect test results again this year and report back again in 2019.

 

Also MANY thanks to Cheri Villines in the lab who processes all the samples and keeps this program going!

 

Sources:

http://www.ncagr.gov/agronomi/documents/StrawberryFertility-Feb2015.pdf

 

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