Ministry of Forests

Sulphur (S) deficiencies in lodgepole pine are widespread in the B.C. central interior, but there is an insufficient basis for prescribing fertilization treatments with both immediate and sustained growth responses. This project builds on the Ministry of Forests’ fertilization research program and careful pilot studies, to combine area-based fertilization response methods with stable isotope tracing of the uptake and fate of S fertilizers. Both elemental S and more immediately plant-available sulphate-S forms are being compared, at operationally realistic addition rates and in combination with nitrogen fertilization. Using two sites that represent typical site and climate conditions in the Sub-Boreal Spruce zone, with low total S concentrations throughout the soil profile, we are comparing relative uptake of these forms, their mobility and tranformations in the soil, and their effects on tree growth. This research will give silviculturists a credible scientific foundation for making better fertilization decisions, and demonstrate serious intent to examine the effects of intensive forest management in B.C. Four growing seasons after fertilization, both foliar concentrations and stable isotope dat