A survey of soils in cotton fields across the Mississippi Delta showed a considerable gradient existed between the surface and subsoil potash nutrient levels. Five-hundred-fifty-five soil samples were taken from the 0-6, 6-12, and 12-18 inch depths. Of these samples, 29.7% were low in potash from 0-6 inches deep; 75.9% were low from 6-12 inches deep; and 89.4% were low from 12-18 inches deep.

Dry fertilizer and lime were banded in the drill continuously from 6-15 inches deep with a dry materials applicator designed and built at the MAFES Delta Branch, Stoneville, MS, in 1985 (9). Early data shows that deep applications of potash into subsoils with either low or very low potash levels may increase lint yield around 85 lb lint/A. Evidence gathered at Stoneville in 1987 indicated that possibly some combination of subsoiling and deep potash application on these soils may reduce dockage for low micronaire.