An amended pine bark growing medium was extracted for varying lengths of time using modified Spurway, Louisiana State Univ. (LSU), and double acid analytical systems. Concentrations of P, K, Ca, and Mg were then determined in the filtrate. As the extraction time was lengthened, the quantity of P, K, Ca, and Mg removed from the medium increased for each system. The concentration and type of nutrients removed varied according to the composition and action of the extractant.
Received for publication July 30, 1982. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.