The pre-sidedress nitrate test (PSNT): Sampling, standards & values to know

University of Minnesota Extension’s two-day field School for Ag Professionals is coming up July 29 and July 30, 2026. If you’re an agronomist, a retailer, dealer or consultant, if you’re a summer field scout - we encourage you to attend these small-group, hands-on sessions led in the field by experienced instructors. 12 Certified Crop Advisor CEUs credits are available! For all the details, including info on lodging, visit z.umn.edu/AgFieldSchool2026

Brad and Jeff continue their discussion about variable rate nitrogen technology by zeroing in on the pre-sidedress nitrate test (PSNT). What are key differences between the PSNT and the pre-plant nitrate test (PPNT)? What growth stage should the crop reach before taking a PSNT? How have sampling and storage procedures evolved from past years? How variable can samples actually be within the same zone and between zones? What should farmers watch out for when interpreting test results? Do different methods of N application produce different PSNT results? How about timing? Manure? What's N's 'critical value' in Minnesota? All these answers and more in-depth discussion on today's episode of the Advancing Nitrogen Smart Podcast.

Guests:

• Brad Carlson, Extension educator (Mankato)
• Jeff Vetsch, Lead researcher, Southern Research and Outreach Center (Waseca)

Additional resources:

• What’s the right PSNT number? New research refines the critical threshold for corn nitrogen decisions in Minnesota
• Video: 6 takeaways on the pre-sidedress nitrate test
• Tips for Accurate Pre-Sidedress Nitrate Tests
• Split-applying nitrogen for corn: Three keys for successful sidedress applications
• Understanding nitrogen in soils

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