Consider soil sampling after grain harvest
Due to wet weather, small grain harvest is running about a week behind schedule. Although growers are anxious to get full-season crops planted, it may be worth their while to take time to collect soil samples directly following harvest. The rains that have delayed harvest may have also washed essential nutrients from the root zone, especially on sandy soils.
Dr. David Hardy, Soil Testing Section chief with the N.C. Department of Agriculture and Consumer Services, urges growers in eastern counties to be proactive in making sure their crops are sufficiently fertilized.
"Prolonged rainfall can move nutrients such as nitrogen, potassium and sulfur deep into the soil profile,” Hardy said. “This is not so much an issue for nitrogen because soil-report recommendations in North Carolina always assume that there is little or no nitrogen present at planting. However, growers who fertilize full-season crops based on soil reports issued before the recent rain events may find themselves putting out insufficient quantities of potash and sulfur for optimal yield.
“If time allows, I encourage growers to collect new soil samples now,” Hardy stressed. “During summer, samples can be processed quickly, and test results are usually posted online in five to seven days. The turnaround time in summer is much quicker than in the winter, when thousands of samples pour in at once and test results can take several weeks.”
Growers who normally send samples to the NCDA&CS soil lab after Thanksgiving may also be interested in altering their sampling schedule so they can get test results more quickly. Lawn and garden samples can nearly always be taken from April through October. Pastures, including those involved in waste management plans, can be sampled in summer. Even samples collected immediately after crop harvest in late summer or early fall can be processed quickly as long as they are submitted to the lab without delay.
“It’s not set in stone that soil samples have to be taken in the fall after a full-season crop,” Hardy said. “Other schedules of sampling can be implemented without major concerns. Keep in mind, too, that sampling every year, especially grid sampling, is unnecessary.”
For advice on the best times and methods to collect agronomic samples, contact your NCDA&CS regional agronomist by visiting www.ncagr.gov/agronomi/rahome.htm.