From mid-October through February, North Carolina farmers send more than 200,000 samples to the state’s soil testing lab.

Eager to plan for the next season, they often find themselves at a standstill as they wait for test results. The situation is unfortunate because soil tests don’t have to be done every year or, for that matter, in the fall.

“Soil testing is one of the best tools available to farmers, and we want to help them use it to their best advantage,” said Agriculture Commissioner Steve Troxler. “That’s why the North Carolina Department of Agriculture and Consumer Services has a statewide network of agronomists to give advice on optimal use of the service. Better-informed growers often discover they have more flexibility with regard to sampling and nutrient application.”

Agronomist Dianne Farrer recently shared a few general rules about soil sampling.

“First of all, soil sampling is not necessary every year, even where GPS is used,” Farrer said. “Only fields subject to nutrient- or waste-management regulation must be sampled annually. These are usually fields where animal waste is applied.

“In typical cropping situations, sandy soils should be tested at least once every two years and clay soils every three to four years,” she said. “If growers change crops or are concerned about leaching, they often sample more frequently, but it is not always necessary. There is an alternate approach.”

Farrer illustrates her point this way: Suppose a grower has clay soils and a soil report that is a year or two old. He doesn’t really need to sample again for another year, but would like to get recommendations for a different crop. Instead of sampling again, he can find his most recent soil report on the Agronomic Services Division’s websiteand use the new “change crops” feature to generate a revised set of recommendations.

Warren Hardy of Seven Springs grows corn, soybeans and wheat. For several years now, he has sampled in spring instead of fall. He stumbled on the idea by accident one year when crop harvests for his area were unusually late.

Because the man who normally samples for him was busy with other fields, Hardy didn’t receive a soil report until May. Several months later, he put out his fall lime application using the recommendations from the spring report.