Determining Nutrient Requirements For Intensively Managed Loblolly Pine Stands Using the SSAND (Soil Supply and Nutrient Demand) Model

Abstract

Nutrient management represents a central component of intensive silvicultural systems that are designed to increase forest productivity in southern pine stands. Forest soils throughout the South are generally infertile, and fertilizers may be applied one or more times over the course of a rotation. Diagnostic techniques, such as foliar analysis and soil testing are available, yet have not been highly successful in identifying fertilizer responsive sites. In most cases recommendations, based on these approaches, lack site-specificity. The Soil Supply And Nutrient Demand (SSAND) model is a mechanistic computer simulation model developed to: (1) diagnose nutrition limitations and (2) determine site-specific fertilization regimes necessary to achieve preset production goals. With this model, the user sets a desired level of production and the model is used to calculate stand nutrient demand. Using mass/flow diffusion theory, the model then simulates the soil supply and compares it to the demand. If the demand is more than supply, fertilization regimes can be tested in order to see which may be the most efficient in meeting plant nutrient demand. This paper provides an overview of the SSAND model and its application.

Citation

Adegbidi, Hector G.; Comerford, Nicholas B.; Li, Hua; Jokela, Eric J.; Barros, Nairam F. 2002. Determining Nutrient Requirements For Intensively Managed Loblolly Pine Stands Using the SSAND (Soil Supply and Nutrient Demand) Model. In: Gen. Tech. Rep. SRS–48. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. pg. 26-30