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Response of young lodgepole pine to nitrogen and sulphur fertilization (E.P. 886.09)
Widespread nitrogen (N) deficiencies and favourable growth responses to N additions have been well documented in immature lodgepole pine forests in the interior of British Columbia. The response of lodgepole pine to N fertilization, however, is variable; some stands respond well and others respond poorly. Fertilization experiments undertaken in the early 1980's indicated that sulphur (S) deficiency, either induced or exacerbated by N fertilization, was a major factor limiting the growth response to N-fertilized lodgepole pine at some locations.
Extensive research has documented the effectiveness of various forms and application rates of S fertilizers on stimulating S uptake and growth of agricultural crops. However, very little parallel research has been undertaken in conifer forests. In 1987, a study was initiated to determine the effectiveness of using different S sources and S application rates to enhance the growth of N-fertilized lodgepole pine. The study was undertaken at seven study locations throughout the interior of British Columbia.
The objectives of this study are to determine the long-term effects of two S sources applied at two different rates on the foliar nutrition and growth of N-fertilized lodgepole pine.
At each study location, each of nine treatments was applied to 15 "single-tree" plots in a completely randomized design. Nitrogen was applied at a rate of 200 kg/ha alone or in combination with different sources and application rates of S. Two types of S, elemental S (S0) and sulphate S, were applied at rates of 50 kg/ha and 100 kg/ha.
At the time of establishment and again after 3 and 6 years, the dbh and height of all 135 "plot" trees at each study site were measured. Foliar nutrient data were also obtained from all treatment plots prior to fertilization and at the time of each re-measurement.
The study is now inactive.
Brockley, R.P. 2000. Using foliar variables to predict the response of lodgepole pine to nitrogen and sulphur fertilization. Can. J. For. Res. 30: 1389-1399.
Brockley, R.P. 2004. Effects of different sources and rates of sulphur on the growth and foliar nutrition of nitrogen-fertilized lodgepole pine. Can. J. For. Res.34: 728-743.
Brockley, R. P. and F. J. Sheran. 1994. Foliar nutrient status and fascicle weight of lodgepole pine after nitrogen and sulphur fertilization in the interior of British Columbia. Can. J. For. Res. 24:792-803.