With sky-high fertilizer prices, you want to take a Goldilocks approach for applications — not too much, not too little but just right. How can you perfectly sync your rates to each field’s needs?
“If you’ve not been regularly soil testing, this year is a great year to start,” says Jason Troendle, economist for The Fertilizer Institute. “You want to completely understand your nutrient needs.”
To harvest the most insights possible from soil tests and more comprehensive soil health assessments, you must aim for uniformity in your sampling methods, says Stacy Zuber, Illinois state soil health specialist with USDA’s Natural Resources Conservation Service.
“Overall, the most important thing is to be consistent with your sampling,” she says. “While fertility tests are usually $7 to $10 per sample, soil health tests are around $50 to $110. These tests can be expensive, so take the time to do them right.”
When you collect samples, Zuber encourages you to note and record all of the following data:
- GPS coordinates of the center of your sample area (or measurements from a permanent post or marker)
- Soil depth of your samples
- Crop or residue on the field when sampling
- Proximity of samples to crop or cover crop row
- Soil moisture and temperature
- Most recent precipitation event
- Date of the most recent tillage activity and type of tillage implement
- Date of application of other amendments (manure, NPK, lime, etc.)
Take a picture of the soil and residues on the soil surface when you sample, Zuber suggests. Also, record your process so you know what you did and can repeat it next time.
“It seems like this is a lot of work, but if you actually want to find out the impact of your management practices, you need to follow these recommendations so you can minimize variability,” she says.
Additionally, when you review your soil test results with your agronomist or other advisers, many of the field and climate factors can impact your soil’s biology, Zuber says.
Sara Schafer uses her Missouri farm roots to cover crop management, business topics, farmland and more.