Nitrogen Sensing Moves Closer to Commonplace

Purdue pair will test concept in field conditions.

Published on: Apr 6, 2009

Bob Nielsen and Jim Camberato bring the mind of scientists to the cornfield. They not only want to know if something works, but how and why it works. And unless they can prove it works in replicated tests, they are cautious about recommending that farmers adapt the practice.


That's why Nielsen and Camberato are just now expanding their efforts into determining if equipment that senses a crop's needs for nitrogen on –the-go and then adjusts the N rate accordingly could be beneficial. They've been experimenting with the notion for several years. Seeing promise in their results, they are planning more testing in '09.


This time, they hope to have a custom sensing rig that they can run over fields one day, using the sensing equipment they're evaluating, then prepare a prescription for N for sidedressing for the next day. The recommendations will be based upon their findings. They will also rely on the data base they have developed from dozens of test trials on nitrogen rates in various locations in Indiana, both on university farms and farmer fields, over the past two years. This information helped them provide data for the N –Rate Calculator tool on the Web sponsored by Iowa State University. Until this year, if a Hoosier farmer wanted to use the calculator, he could choose Illinois data, then adjust rates upward slightly to account for lower organic matter contents on most Indiana soils, compared to many Illinois soils. Now he can choose Indiana data that should be most beneficial in preparing accurate calculations for his farm.


This same data will be useful as the pair of Purdue University Extension agronomists decide how much N to apply in plots, based on what they find from their sensor readings. If the summer goes as planned, they hope to have some interesting information to report on next fall and winter. They intend to do the work both at university farms and on farm fields where farmers volunteer to cooperate with them.


Sensing technology has been available in the past. Soil Doctor appeared roughly two decades ago as an applicator that could sense and adjust rates for N in corn on the go, based on conditions it electronically sensed in the soil. The makers of the tool were reluctant to explain how it worked, so it wasn't evaluated across a widespread area by university researchers.


Another technology for N sensing, marketed as Green Seeker, is commercially available now. However, so far it has been used more for applications of N on wheat in the western states rather than for N applications in sidedress format for corn in the Midwest, Nielsen notes.


The technology the Purdue agronomists are using is actually made by another company than the one that makes Green Seeker equipment. They hope to be able to say more about the future of the concept by this time next year, if not earlier.