OptRx™ Crop Sensors: Your Questions Answered (Part 1)

Crop sensing technology is something growers tend to have many questions about, and most of the questions relate to one main concept – how crop sensors can help your operation. With that being said, I’ve put together a series of three blog posts in an effort to answer some of the common questions regarding our OptRx crop sensor system.

How can OptRx help achieve greater plant health? One of the biggest challenges in agriculture is managing nitrogen. There are many tools to assist with nitrogen management once it’s on the soil, but even then you have to hope for cooperation from Mother Nature. That’s where OptRx crop sensors come in, using a system that applies nitrogen based on crop vigor. By evaluating crop vigor, and taking field variability and crop conditions into account, OptRx applies the right amount of nitrogen to each plant.

How does OptRx determine Nitrogen rate? OptRx works by measuring the reflectance of light it shines on the corn canopy.  OptRx measures reflectance of Near Infrared (NIR) light to determine plant biomass (amount of crop vegetation).  Reflectance of visible band light is used to detect nitrogen in the plant.  OptRx combines reflectance of both light bands to calculate a vegetation index that represents the vigor of the crop.  For example, nitrogen deficient corn plants have lower vegetation index numbers than plants with sufficient nitrogen. OptRx uses the vegetation index to determine how much nitrogen plants need.  OptRx must first identify the vegetation index number that represents a plant with sufficient nitrogen available.  This is called the vegetation index reference value.  Vegetation index reference value is determined by driving the applicator over the healthiest looking plants for a minimum of five minutes. OptRx prescribes nitrogen by comparing the real time vegetation index number to the reference value.  The lower the real time vegetation index compared to the reference, the higher the prescribed nitrogen rate.  The principle is to apply the right amount of nitrogen in the right spot. OptRx works the same way in determining the appropriate rate of nitrogen application for both corn and wheat plants.