Sulphur Deficiencies in Lodgepole Pine : Occurrence , Diagnosis , and Treatment

Sulphur (S) deficiencies are widespread in lodgepole pine stands in the British Columbia central interior. Low soil S availability can limit tree growth responses to nitrogen (N) fertilization. Refined diagnostic criteria and decision-making tools enable more reliable identification of stands that will respond to inclusion of S in fertilizer prescriptions. Most research and large-scale aerial fertilizer operations have used soluble sulphate-S sources, but evidence is accumulating that elemental-S provides equally satisfactory long-term amelioration of S deficiencies. New research is using stable isotope tracer methods to improve understanding of the fate and transformations of S fertilizers. For sites where fertilization may not be feasible, soil conservation is particularly important for preventing further losses of limited S.