“Once GS-30 is reached, growers should immediately collect tissue samples and matching above-ground biomass samples,” Knox said. “This is especially true if wheat is already big and lush due to warmer weather or early planting dates.”

At GS-30, tissue sampling involves cutting wheat plants about one-half inch above the ground from 20 to 30 representative areas throughout a field. Generally, two large fistfuls of leaves make a good sample. Dead leaves and weeds should be removed.

Biomass samples, on the other hand, should contain all the above-ground wheat-plant tissue from one representative, 36-inch section of row. In broadcast fields where there are no rows, growers should collect all the plants from one square yard. The sample should be placed in a paper bag, with the sample ID from the corresponding tissue sample and the word “biomass” written on the bag.

The collecting of biomass samples may be fairly new to growers. The idea was first broadly implemented in 2010 based on research by Randy Weisz of North Carolina State University. He developed a method of using biomass weight along with tissue test results to calculate more site-specific nitrogen recommendations.

His approach takes into account crop-growth differences due to planting date, row spacing and moisture levels. For wheat grown on large acreages of poorly drained soils, however, growers should consult with an agricultural adviser about whether this method is likely to be useful.

Upon receiving their NCDA&CS plant analysis report, growers should first look for the biomass and nitrogen percentage values. These values and certain crop planting details help determine the appropriate nitrogen rate, based on the interactive tool developed by Weisz. This method is explained fully online at www.smallgrains.ncsu.edu/_Pubs/PG/Nitrogen.pdf.

North Carolina growers wanting more information about this method should contact their NCDA&CS regional agronomist, county Cooperative Extension agentor other agricultural adviser. Regional agronomists, in particular, can offer advice on how to collect and submit tissue and biomass samples, and how to interpret and use plant analysis report data.

Contact information is available online at www.ncagr.gov/agronomi/rahome.htm.

(The mild winter in North Carolina has caused the wheat crop to move ahead of schedule. This may cause a need to change fertilization plans. For a look at that situation, visit http://southeastfarmpress.com/grains/rapidly-developing-wheat-changes-nitrogen-plans).