Intensive Pre-Sidedress Nitrogen Testing (PSNT)

Many acres of corn across our area are established with good stands and it is on its way into the summer growing season.  Soon it will be time to apply side-dress nitrogen and concentrate on the nutrient needs of the crop and prepare it for the rapid growth phase that is soon approaching.

Given the increased price of nitrogen and the strong crop prices that are available some of our customers are considering a more intensive pre-sidedress nitrogen testing program to help them better place their fertilizer dollars where it has the best chance of making the greatest impact on harvested yield.  Based on university data across the midwest it is strongly recommended that sample cores for PSNT be collected at a 12” depth to capture more of the mobile nitrogen as it begins to move downward through the soil profile.  For those interested in increasing the intensity of their sampling program it may be useful to collect PSNT samples on a 5-10 acre grid or zone pattern of 8-12 cores per sample.

It may be most useful to concentrate sampling efforts on fields with historically medium to high yield potential with good plant stands and fields with likely variable levels of nitrate availability such as areas that have had applications of manure, municipal waste and other organic forms of nitrogen.

It may be advantageous to adjust nitrogen application rates based on actual measured nitrate levels in the soil at side-dress time.  If you have questions or would like assistance with your pre-sidedress nitrate testing plan please contact your agronomist at A&L Great Lakes Laboratory and we would be happy to assist you.