Effects of nitrogen and phosphorus fertilization on the growth and nutrition of hybrid poplars on Vancouver Island |
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| Authors: | K R Brown R van den Driessche |
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| Institution: | (1) British Columbia Ministry of Forests, Victoria, BC, Canada;(2) Present address: K.R. Brown and Associates, 4043 Zinnia Road, Victoria, BC, Canada;(3) Present address: Centre for Forest Biology, University of Victoria, P.O. Box 1700, Victoria, BC, Canada |
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| Abstract: | The effects of nitrogen (N) and phosphorus (P) rates, P source, and method of P application were tested on growth and nutrition of four clones of hybrid poplar (Populus trichocarpa Torr. & Gray ×P. deltoides Bartr. ex Marsh or P. trichocarpa×P. maximowiczii A. Henry) in a plantation on Vancouver Island. Treatments were applied shortly after planting. Nitrogen (0, 500kgNha–1) was supplied as ammonium sulfate (AS); half of the AS was added at the start of the second growing season. Phosphorus (0, 100, 200kgPha–1) was supplied as triple super phosphate (TSP), rock phosphate (RP), or diammonium phosphate (DAP) and banded or broadcast. Over four growing seasons, stem volumes increased with AS and P additions. The effects of AS and P each were greatest when the other was also added. Volume was greater when P was applied at 100kgha–1 than in the P control and did not significantly increase further at 200kgPha–1. Phosphorus additions were more effective when added as TSP or DAP than when added as RP, but only in P100 and when banded. Banding increased volume when P was applied at 200kgha–1, but increases were significant only for DAP fertilized trees. Roto-tilling associated with the banding treatment also increased volume when AS and P were not added. Rankings of clones with respect to stem volume varied with N supply and changed over time. |
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| Keywords: | Fertilizer placement Hybrid poplar Nitrogen Phosphorus |
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