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The effects of nitrogen, sulphur and boron on the nutrition, health and growth of immature lodgepole pine (E.P. 886.12)
Low to marginal foliar boron (B) levels are a characteristic found in many immature lodgepole pine forests in the interior of British Columbia. Low foliar B levels in the north-central interior are often found in stands established on glacial morainal soils derived from igneous rocks, with thin surface organic layers. These sites are often susceptible to soil moisture deficit during the growing season. Boron deficiencies are well documented under these soil conditions. Although less common, low foliar B levels have also been documented in immature lodgepole pine forests growing on coarse-textured glacial outwash soils in wetter climatic regions in south-eastern British Columbia. In high rainfall environments, sandy soils may be particularly susceptible to B deficiencies, since borate is very easily lost in leaching.
This study was initiated in 1990 on a site adjacent to a lodgepole pine stand in which severe top dieback and low foliar B levels were documented following N fertilization in the mid- 1980's. The study site is located in the Interior Cedar-Hemlock (ICH) biogeoclimatic zone in southeastern British Columbia.
The objectives of this study are to: i) determine the effects of boron and sulphur, applied singly and in combination, on the nutrition, health, and growth of nitrogen-fertilized lodgepole pine, and ii) examine the nature of a boron x sulphur interaction.
Each of five treatments was applied to five, area-based plots in a completely randomized design. Each plot consisted of an inner 7 m radius measurement plot surrounded by a 3-m treated buffer. Each measurement plot contained approximately 20 lodgepole pine trees. In addition to an unfertilized control, fertilizer was applied as N (300 kg/ha) and N+S (300 kg N/ha + 75 kg S/ha) alone, and in combination with B.
The diameter at breast height and total height of all trees were measured at the time of establishment and again after 3, 6, and 9 years. 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. 2003. Effects of nitrogen and boron fertilization on foliar boron nutrition and growth in two different lodgepole pine ecosystems. Can. J. For. Res. 33: 988-996.