Superphosphate and urea produced large volume increases in 13-year-old maritime pine,Pinus pinaster(Aiton) growing on a lateritic podzolic soil. Growth curves over two years show the detailed effects of the fertilizers on seasonal growth. Volume increments were increased three-fold by the application of 800 lb superphosphate and 400 lb urea per acre, at a cost in fertilizers of 12 cents per cubic foot. Further volume increments can be expected from the original fertilizer application.
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