Wheat producer Warren Hardy is pleased with his crop this year. The Wayne County farmer put out less fertilizer and achieved a yield of about 80 bushels per acre over 160 acres.

Hardy did this by applying spring nitrogen based on the results of an agronomic test known as plant tissue analysis, which is available through the North Carolina Department of Agriculture and Consumer Services.

“I had taken tissue samples sporadically in previous years,” Hardy said, “but it was mostly for diagnostic purposes. I was doing it to identify problems. My fertilization program had been based on soil samples and standard recommendations alone.”

Plant tissue analysis involves collecting representative plant leaves from random locations throughout a reasonably uniform field.

The sample is sent to a laboratory, which measures plant-nutrient content. The test is so sensitive that it can detect nutrient deficiencies before plants display any visible symptoms. Even so, the best use of tissue analysis is as a monitoring tool to prevent problems in the first place.

In early March, NCDA&CS regional agronomist Dianne Farrer encouraged Hardy to use tissue analysis to fine-tune his spring nitrogen application.

She demonstrated the sample collection process, which involves not only routine tissue samples to measure nutrient content but also corresponding biomass samples to estimate crop growth and vigor.

Both types of data, along with information about row spacing, can be used together to arrive at precise, field-specific nitrogen recommendations, using a method developed by Randy Weisz and Ron Heiniger at North Carolina State University.

“I advise growers to take advantage of tissue testing because soil tests do not actually measure nitrogen,” Farrer said.