News Release Distributed 02/11/14

ALEXANDRIA, La. – Farmers can improve the efficiency of their fertilizer applications with a combination of soil electroconductivity, soil sampling and crop-yield monitors, according to two LSU AgCenter agents who conducted a workshop on precision ag technology.

LSU AgCenter agents Dennis Burns, from Tensas Parish, and R.L. Frazier, from Madison Parish, gave an overview of the system Monday (Feb. 10) at the Dean Lee Research Station.

“We’re trying to determine what’s needed and where it’s needed,” Frazier explained.

Frazier said the system takes into account the variations of soil types within a field determined with a Veris rig to measure soil electroconductivity and the nutrient needs in different areas of a field revealed through soil testing.

The Veris rig transmits a 12-volt electrical current into the soil to delineate the soil types, and a GPS unit on the machine is used map the different soils.

The Veris rig can be used in soil with adequate moisture for planting, Frazier said. “If it’s too wet to plant, it’s too wet to run the Veris machine.”

The readings collected by the Veris rig are correlated to the nutrient needs found from soil testing, either through grid sampling or zone sampling. A computer program is then used to make a fertilizer prescription.

Frazier said the intent of the program is not to increase yields but to improve net income from a crop. “We’re pushing for the highest rate of return per acre,” he said.

The system will be used to test a variable seeding rate for corn this year, Burns said. A cotton seeding rate study is being considered.

By applying only the necessary amount of fertilizers, farmers will become better stewards of the land, Frazier said. A pending lawsuit could result in fertilizer restriction similar to those imposed in some parts of Florida, he said.

A yield monitor that shows a fairly uniform yield across a field indicates that a correct fertilizer application has been made. But Burns said a yield monitor has to be calibrated for different plant varieties to be accurate, especially for cotton.

Frazier estimated that 10 percent of the farmers in north Louisiana are using the system.

“Once they try it and get it working where the light bulb goes off, they want it,” Burns said.

Frazier said a farmer cannot neglect critical areas such as proper drainage. “You’ve got to get the basics of agronomics right first,” he said.