Source:  NCDA&CS, 3/16/10

Some areas of eastern North Carolina have had more than 25 inches of precipitation since early fall. For sandy soils with little organic matter, this means that reserves of water-soluble nutrients such as potassium and sulfur have been leached out of the crop root zone. When choosing a fertilizer this spring, growers will want to pay very close attention to these two nutrients.

To help growers deal appropriately with this situation, the N.C. Department of Agriculture and Consumer Services is offering some guidelines.

“A base application of about 100 pounds of potash per acre should provide sufficient potassium to crops like corn, cotton and soybeans,” said Dr. David H. Hardy, NCDA&CS Soil Testing Section chief. “On sandy soils prone to leaching, especially those with cation exchange capacity (CEC) values of three or less, it is a good idea to split the potash into applications. This safeguards potential loss if we continue to have a wet spring.

“With regard to sulfur, I recommend 20 to 25 pounds per acre,” Hardy said. “I also want to warn growers against applying too much phosphorus as they put out potash and sulfur. Phosphorus does not leach readily from soils and has accumulated in many agricultural soils over years of farming. Applying unneeded phosphorus can be expensive and will not improve crop yield.”

North Carolina growers concerned about soil fertility and crop fertilization issues this year are advised to contact their NCDA&CS regional agronomist. Agronomists can provide advice on the timing of potash applications. They can also help growers reassess soil test report results that were received early last fall before the rain and modify the recommendations based on current conditions. To find the agronomist assigned to a particular county, call (919) 733-2655 or visit www.ncagr.gov/agronomi/rahome.htm.