Surface application of cement kiln dust and lime to forages: Effect on soil pH

This 2-yr field trial on forage plots compared the relative effectiveness of surface applications of cement kiln dust (CKD) to lime for raising soil pH. Seven soil treatments, in four blocks, were established at four low pH sites, which were: (1) a check plot; (2) lime at the recommended application (L), based on soil test for each site; (3) lime at 1.5 × L; (4) CKD at L; (5 ) CKD at 1.5 ( L; (6) CKD at an equivalent to lime basis; and (7) CKD applied at 1.5 times the equivalent to lime basis, where equivalence was based on CKD’s apparent neutralizing value equal to 75% that of lime. Soil pH was determined before applications and was monitored afterwards for two growing seasons. Two months after surface application, the CKD increased soil pH more than lime, despite its apparent neutralizing value being only 75% that of lime. Effects were greater closer to the soil surface and trends persisted through the following year. The CKD appears to be a quick-acting lime substitute due to its fineness (more than 99% passed through 100-mesh compared with 58% of lime). Key words: Forage, lime, cement kiln dust, pH