By Scout Nelson
The pre-sidedress nitrate test (PSNT) is an important tool used by farmers to manage nitrogen levels more effectively during the growing season. In a recent episode of the Advancing Nitrogen Smart Podcast, experts Brad Carlson and Jeff Vetsch continued their discussion on variable rate nitrogen technology, focusing on how PSNT can help improve crop decisions.
Brad Carlson, an Extension educator based in Mankato, and Jeff Vetsch, a lead researcher at the Southern Research and Outreach Center in Waseca, explained the key differences between PSNT and the pre-plant nitrate test (PPNT). While PPNT is conducted before planting to estimate available nitrogen, PSNT is performed later in the season to measure nitrogen levels when crops are actively growing. This makes PSNT more useful for adjusting nitrogen applications based on real-time crop needs.
Timing is critical when using PSNT. The experts noted that farmers should wait until crops reach the appropriate growth stage before collecting soil samples. Taking samples too early or too late can lead to inaccurate results and poor decision-making.
The discussion also highlighted how sampling and storage methods have improved over time. Proper sample handling is essential to maintain accuracy. Farmers must also be aware that nitrogen levels can vary widely within the same field or even within the same management zone. This variability makes careful sampling and interpretation very important.
Carlson and Vetsch also addressed how different nitrogen application methods, including fertilizer type, timing, and the use of manure, can influence PSNT results. These factors should always be considered when analyzing test data to avoid over-application or under-application of nitrogen.
Another key point discussed was the “critical value” of nitrogen, especially in Minnesota. Understanding this value helps farmers decide whether additional nitrogen is required for optimal crop growth.
The podcast provides valuable insights for farmers looking to improve nutrient management practices. Listeners are encouraged to subscribe to the Nutrient Management Podcast for the latest updates. Questions and comments can be sent via email to nutmgmt@umn.edu.
Advancing Nitrogen Smart is supported by Minnesota farm families through their corn check-off investment with Minnesota Corn, helping promote efficient and sustainable farming practices.
Photo Credit: gettyimages-shotbydave
Categories: Minnesota, Crops, General