Top Crop Manager

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Tissue-testing tips shared at SCDD

July 9, 2024  By Top Crop Manager


Horst Bohner, OMAFRA soybean specialist, discusses various nitrogen supplement treatments applied to soybean trial plot. Photos by Top Crop Manager.

This year’s annual Southwest Crop Diagnostic Days (SCDD) was held at the Ridgetown, Ont., campus of the University of Guelph on July 3 and 4. Field crop specialists from the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) and the University of Guelph, as well as a few other industry speakers, were on hand to offer eight practical agronomy sessions. The event is an excellent opportunity for certified crop advisers (CCAs) to earn necessary continuing education credits, and for anyone connected to field crop production to catch up on the latest, most relevant concerns and research in the industry.

One such session had Joanna Follings, OMAFRA cereals specialist, and Ben Rosser, OMAFRA corn specialist, present on tissue-testing, more specifically in the context of fertility management.

Why tissue test?

  • Confirm visual symptoms of nutrient deficiencies, disease, etc.;
  • Identify underlying deficiencies;
  • Plan for future fertility programs and identify trends; and
  • Improve yields.

Rosser (left) and Follings explain corn sampling tactics to attendees.

On the topic of collecting samples, here are some best practices the duo listed:

  • Timing matters:
    • Avoid sampling during peak daytime temperatures (late morning/early afternoon);
      • The temperatures at which it’s possible to sample, regardless of timing during the day, differ between crops, but in general sample in the morning or late afternoon/evening.
    • Avoid sampling after a herbicide application;
      • According to Follings, some British high-yield wheat croppers advised that they also avoid sampling following fungicide applications;
      • The window of time following application differs depending on whether it’s fungicide or herbicide.
  • Avoid contaminating tissue sample with soil:
    • Rosser suggests cutting plant above the soil to avoid contamination, instead of pulling the plant from the ground;
    • Soil contamination largely affects micronutrient level measurements.
  • Sample management:
    • Collect and store tissue samples in paper bags;
      • Samples stored in Ziploc/plastic bags tend to rot and are unusable;
      • Do not freeze tissue samples – nutrients can leach out when the sample is thawing, which will affect the results of the test;
      • Deliver the sample directly to the lab, if possible;
      • Dry samples out slightly – in the sun, if possible, or in an oven at 65 C or lower.

Danny Jefferies, OMAFRA soil management specialist, horticulture, shows the results of blue dye water infiltration demonstration.

The other seven sessions included topics such as corn rootworm management, disease identification and management, winter canola as a rotation addition, crop sensitivity to herbicides, and more.

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