When and at what rate nitrogen fertilizer should be applied are major questions for today’s corn producers. Nebraska Extension is helping answer these questions through Project SENSE, which stands for Sensors for Efficient Nitrogen Use and Stewardship of the Environment.

Over the last 40 years, producers have greatly increased fertilizer efficiency, but that gain in efficiency may be starting to plateau. This points to the need to adopt new technologies to reach efficiency increases producers are used to seeing. Project SENSE, implemented by Nebraska Extension for the first time last year, is focused on improving nitrogen use efficiency by fertilization during the growing season.

Richard Ferguson, Nebraska Extension Soil Specialist, is leading the project, which focuses on using crop canopy sensors to direct variable-rate, in-season nitrogen application in corn. The sensors are attached to the nitrogen applicator and work by emitting light onto the crop canopy. Photodetectors on the bottom of the sensor measure specific wavelengths of light that are reflected by a leaf. The wavelength information is recorded by the crop canopy sensor and combined to form an index that has been correlated to the nitrogen status of the crop. This information is used by the system to generate a recommended rate of additional fertilizer that is then applied to the crop in real time.

“Farmers aim to apply fertilizer at a time and rate that will maximize yield,” Ferguson said. “Project SENSE can help them better define what the appropriate rate should be based on how stressed the plant is for nitrogen.”

Project SENSE was implemented at 17 research sites across five natural resources districts in Nebraska in 2015.

Results from the first growing season are encouraging. Use of the sensors reduced the nitrogen rate by 40 pounds per acre compared with the grower’s standard management practice. While this did cause a slight yield reduction of five bushels per acre, producers saw an overall increase in profit because of reduced fertilizer cost. Researchers estimate that the sensing equipment would pay for itself in two to three years in a typical Nebraska farming operation.

The project is a collaborative effort of Nebraska Extension, Nebraska Corn Board, and Nebraska Natural Resources Districts. This summer demonstrations and field days will be held in each Natural Resource District where Project SENSE is conducting research. Dates and locations will be announced in CropWatch (Website: cropwatch.unl.edu) when available.

For more information or assistance, please contact Allan Vyhnalek, Extension Educator, Nebraska Extension in Platte County.  Phone: 402-563-4901 or e-mail avyhnalek2@unl.edu