Forest Investment Account (FIA) - Forest Science Program
FIA Project Y051210

    Sulphur fertilization of lodgepole pine: a stable isotope tracer study
Project lead: Sanborn, Paul
Contributing Authors: Sanborn, Paul T.; Brockley, Robert P.; Mayer, Bernhard; Yun, Misuk; Prietzel, Joerg
Imprint: Victoria, B.C. : Ministry of Forests. Forest Science Program, 2005
Subject: Forest Investment Account (FIA), Lodgepole pine, British Columbia, Nutrition, Fertilizers
Series: Forest Investment Account (FIA) - Forest Science Program
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. - Sulphur deficiencies in lodgepole pine
Widespread sulphur (S) deficiencies have been detected in lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) stands in the Sub-Boreal Spruce biogeoclimatic zone of central interior British Columbia. Field experiments in this region have shown that addition of sulphate-S to nitrogen (N) fertilization treatments rapidly increases foliar S concentrations, and usually improves tree growth responses relative to N-only treatments. However, there is an insufficient scientific basis for choosing this S form over more slowly available elemental S-based fertilizers. To address this knowledge gap, this study was begun in 2001 to compare the behaviour of sulphate-S and elemental-S fertilizers in an area-based fertilizer trial, using stable isotope tracer methods to examine the fate and transformations of fertilizer S. Fertilizer treatments were applied to two lodgepole pine stands, near Fraser Lake (Holy Cross site) and in the Bowron River valley (Kenneth Creek site), in fall 2002. This establishment report reviews background literature relevant to this study, details the experimental design and methods used, and documents the initial soil and stand conditions at the time the experimental treatments were installed. Pre-treatment analyses indicated that mineral soils at these sites have low total S concentrations, which are typical of the British Columbia central interior and are among the lowest reported in the temperate and boreal zones worldwide. Concentrations of other total and (or) available soil macronutrients (N, Ca, Mg, K, P) were usually higher at the Holy Cross site than at the Kenneth Creek site. Lodgepole pine foliar analyses indicated that S deficiency was more pronounced at the former site. Ratios of background S stable isotopes in lodgepole pine foliage and soils differed sufficiently from those of the applied S fertilizers to make a tracer experiment feasible. - Sulphur fertilization of lodgepole pine
Paul Sanborn ... [et al.].
Related projects:  FSP_Y062210FSP_Y073210


Technical report (0.9Mb)
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