Presidedress Nitrogen Test.
- Farms that grow corn and side-dress nitrogen should do preside-dress nitrogen tests. Farms who don't side-dress nitrogen may want to do a PSNT to see if it makes sense for them to try to incorporate nitrogen fertilizer side-dress into their practices. At this time there are PSNT recommendations for field corn, sweet corn, pumpkins, winter squash, and peppers, but not for any other crops.
- Quicker Results.
- Normally the PSNT soil sample must be dried before sending and the results are mailed back both of which delay getting results sometimes taking up to a week. Last year I used a special sample bag that does not require drying sample so you can mail immediately and had results returned via web or fax so was able to often turn around results in 48 hours.
- Why PSNT?
- Based on numerous field studies in Vermont, researchers at UVM developed the PSNT, the only real test for nitrogen. The test must be done during the growing season at the time plants need to have nitrogen because nitrogen availability in the soil is greatly influenced by weather (temperature, rainfall), soil leaching, and microorganism activity.
The PSNT tests for the actual amount of nitrate found in the soil at side-dress time and recommendations are based on the test results and your projected yields, manure application and previous sods or legumes and soil drainage. These recommendations are better for your fertilizer management decisions than regular soil test recommendations.
In a regular soil test there is no lab test for nitrogen. Regular soil test nitrogen recommendations are estimates of what you need for nitrogen based only on your projected yields, manure application and previous sods or legumes, and soil drainage.
The proper time to do the test is when the corn is 8 to 12 inches tall (to a depth of 12 inches).
PSNT costs about $7.00 per test (UVM lab fee + Postage) You can have your fertilizer dealer do it or if you are a client of District's Crop Consultant Program the Crop Consultant can do it for you.