On-the-go sensor equipment, first built by Greenseeker and now also manufactured by CropCircle, is attached to field equipment or carried as a hand-held unit and provides information about the relative vigor of a plant. Unlike aerial imagery, it provides instantaneous data, while using the same type of data output — NDVI, or Normalized Difference Vegetation Index — as aerial images.
Why now? Barnes says that several of Cotton Incorporated‘s State Support Programs (grower-lead programs to set research priorities specific to their state) have expressed a high level of interest in the technology through research on a local level, and Cotton Incorporated has done a lot of work on sensor technology from its core program. Finally, Barnes says that “the technology now is getting pretty mature in that we have a good interface between some of the sensors and the controllers. So from a practical standpoint you can just go and collect data.” But, what exactly to do with the data is the big question.
The low-hanging fruit for on the go sensors is applications of PGRs and defoliants, Barnes explains. “We had some preliminary on-farm trials that showed good promise to use the sensor data for real-time variable-rate PGR and defoliant applications.”
Like aerial imagery the sensors measure vegetation, so the PGR algorithm is pretty easy to understand — spray that which is excessively green, turn off the spray when it’s not. “And at the end of the season, you are trying to manage green areas where the plant needs more defoliant, so again it’s not a complicated formula, it’s really a one to one relationship between sensor output and product output,” says Barnes.
He says that on-the-go sensors could be applied in the field immediately if a grower wanted to do it, but Cotton Incorporated is aiming to improve the economic benefit of adopting the technology by getting after a bigger issue: variable rate nitrogen.
The big stumbling block is that the consequences for getting nitrogen wrong in cotton are dire — too much creates a big plant that calls out to insect pests, and too little is a yield robber.
To get at the issue, studies are taking place in several states including Missouri, Mississippi, Tennessee, Georgia, North Carolina, South Carolina, Arizona, New Mexico, Oklahoma and Texas.
Beyond economics, Barnes says the cotton industry’s increasing focus on sustainability is another reason to look at managing nitrogen more effectively.
When we look at the energy footprint to produce cotton, if we are in a production system that uses nitrogen from a synthetic source, then that is the biggest energy use,” he says. “We need to be ready with the tools to manage the input as effectively as possible.”