Abstract
An effective operational forest fertilization program requires diagnostic systems that accurately identify a site's nutrient status and also predict stand responses to fertilizers. Diagnostic criteria evaluated over the past 20 years have included visual symptoms, soil analysis, foliar analysis, soil groups, greenhouse studies, experimental fertilization trials, and empirical response models. Each system has associated advantages and limitations when applied on an operational level. The diagnostic techniques used by forest managers will depend on reliability, costs of time and materials, and technical skills needed for implementation. A survey of industrial organizations having operational forest fertilization programs indicated that most were using a combination of methods, in the belief that simultaneous use of several criteria improves the accuracy of diagnosis. In the Lower Coastal Plain, managers most frequently cited soil groups, soil analyses, soil drainage classes, and results from experimental field trials as reliable criteria for making "at-time-of-planting" prescriptions. Knowledge required to manage the nutrition of established stands was generally considered to be more complex. Foliar analysis, soil groups, soil drainage classes, stand attributes, and fertilizer field trials ranked highest in perceived reliability. South. J. Appl. For. 12(3):153-160.
