The end of the growing season is an ideal time for your growers to reflect on what went right and what could be improved. However, without the right information and data in front of them, it can be hard to chart the best course for next year’s planting.
Soil health testing gives both growers and you, as a retailer, a clearer picture of current fertility conditions. But understanding how to read soil test results is only the first step. Comparing results year to year can reveal trends in soil nutrient management and help growers make more informed decisions for the season ahead.
When is the best time to do this? January is the sweet spot, when harvest is in the rearview mirror and spring planting is just around the bend.
Compare soil nutrient analysis trends, not just numbers
A single phosphorus, potassium or soil pH result can tell you something about current soil fertility conditions. It’s a snapshot of the story your soil is telling. But with several year’s worth of soil tests, that story becomes more vivid and informative.
By comparing several years of soil nutrient analysis, you can help growers understand how soil fertility is changing over time.
- Is soil pH gradually declining?
- Are P or K levels being drawn down?
- Are nutrient levels accumulating above the desired range?
- Are some areas of the field changing faster than others?
- Does the current test reinforce something seen in previous years, or is it an anomaly worth investigating?
These questions can help identify nutrient deficiencies or excesses and lead to more useful fertility conversations with growers before they head to the field in spring.
Use soil pH trends to improve soil nutrient management
Soil pH is one area where soil health and nutrient management overlap. Tracking pH trends can help identify fields where lime applications may need adjustment. Because pH can vary within the same field, grid or zone sampling can help identify where lime is actually needed rather than relying on one uniform rate.
University of Georgia researchers found that variable-rate liming reduced lime costs from about $60 per acre to $32 per acre in one example. Even after adding roughly $10 per acre for precision sampling and analysis, the approach still saved about $18 per acre.1
As you review soil tests with your growers this winter, look for fields with declining pH or significant variability. Those fields may be good candidates for more intensive sampling and variable-rate lime applications before spring.
Turn soil results into field-specific fertilizer plans
Once you help your growers understand how to measure soil nutrients and where those levels are headed, use that information to build field-specific fertilizer recommendations. A soil nutrient analysis, paired with locally calibrated recommendations, can help determine which nutrients are deficient and how much supplemental fertilizer may be needed.
Soil test levels can indicate whether growers should build nutrient levels, maintain them based on crop removal, or reduce applications when soil levels are already adequate.2
Nitrogen recommendations may require additional information, including soil type, organic matter, previous crops, manure applications and soil nitrate testing. Micronutrient recommendations should also be based on soil or plant analysis rather than assumed deficiencies.3
January gives you time to turn last season’s soil test data into a more targeted soil nutrient management plan for the year ahead. Comparing trends and building field-specific recommendations now gives growers a clearer fertility plan before spring gets busy.
Experts are available to help you make your soil test analysis decisions. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative.
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Endnotes
- Variable-Rate Liming Pays for Itself.” Extension Precision Ag and Irrigation, University of Georgia, 6 Feb. 2023, precisionagirrigation.extension.uga.edu/2023/02/variable-rate-liming-pays-for-itself/.
- Warncke, Darryl, Jon Dahl, and Lee Jacobs. Nutrient Recommendations for Field Crops in Michigan. Extension Bulletin E2904, Michigan State University Extension, Aug. 2009,www.canr.msu.edu/fertrec/uploads/E-2904-MSU-Nutrient-recomdns-field-crops.pdf.
- Bundy, L. G. Corn Fertilization. Publication A3340, University of Wisconsin-Extension, Cooperative Extension, 1998, soilsextension.webhosting.cals.wisc.edu/wp-content/uploads/sites/68/2014/02/A3340.pdf.
