Nitrogen (N) management is probably the single most variable production input growers face in agriculture. And with the continued increase in fertilizer costs, application efficiency is becoming increasingly important.

Researchers at Ohio State University are now evaluating the use of optical sensors in N management. Optical sensors that can be mounted on a tractor are being developed in an attempt to increase N efficiency by assessing a plant's overall health using red and near infrared (NIR) light. Healthy plants will absorb more red light and reflect higher amounts of NIR light than unhealthy plants.

By comparing the health status of the crop to an N-rich strip, growers can determine if the soil is providing enough N or if additional N should be applied.