Fertilization of Established Trees

Abstract

Prior to this study the two senior authors, as plant pathologists, had recommended fertilization as a preventive or corrective control measure for several tree diseases. It was recognized, however, that the procedures for fertilizing established trees had not been thoroughly subjected to scientific evaluation; more experimental data were needed. While cooperating with the junior author at the Morton Arboretum, Lisle, Illinois, on plant disease studies in 1962 the senior authors learned of an experimental area in the Arboretum which contained uniform, established trees in 100-tree blocks with tree spacing intervals optimum for fertilizer trials. In this area a cooperative study was initiated with the Morton Arboretum. Following the early successful attempts at measuring growth response to fertilizer applications in 1963 and 1964 at the Morton Arboretum, the senior authors expanded the study with trials at four additional sites in Illinois through 1968.