This is the first of a multipart series on how to make site-specific, nitrogen rate recommendations using the SoilDx FertiSaver-N system.
- Measuring the organic N fraction of soil is a useful approach to determine soil N availability.
- The Illinois Soil Nitrogen Test is a simple chemical test to measure the amino sugar N fraction in organic matter.
- The results of the test need to be interpreted in a context dependent manner: It is not sufficient to look for simple thresholds in the ISNT value to make nitrogen rate predictions. Other factors such as soil type, depth, available water, and soil pH are critical to accurate recommendations
- The ISNT has been evaluated independently by several groups and on several crops beyond corn in the Midwest.