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 proposal 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 (100 kg S/ha) and in combination with nitrogen fertilization (300 kg urea-N/ha). Fertilization treatments were applied in fall 2002 at two lodgepole pine sites that represent typical site and climate conditions in the Sub-Boreal Spruce zone. Characterization of S fractions in unfertilized representative soil profiles at both sites show vertical patterns of S concentration and relative abundance of S fractions, dominated by organic S forms, that are typical of Brunisolic, Podzolic and Luvisolic soils in the B.C. central interior. Initial results from foliage and soil sampling in fall 2003 indicate the expected more rapid uptake of S applied in soluble sulphate form, as demonstrated by both concentration and isotopic data.
Paul Sanborn Rob Brockley, Bernhard Mayer.
Sanborn, Paul T., Brockley, Robert P.; Mayer, Bernhard. 2004. Sulphur fertilization of Lodgepole Pine: a stable isotope tracer study : technical report to Forest Innovation. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report