Autumn fertilization in the nursery affects growth of Picea abies container seedlings after transplanting

Second-year Norway spruce seedlings [ Picea abies ( L.) Karst.] grown in containers were divided into three fertilization levels in August [ 5, 15 and 25 mg nitrogen (N) seedling(-1)]. The resulting foliar concentrations of N were 11.0, 13.1 and 15.8 g kg(-1), respectively. Seedling height ( mean 26.0 cm) did not differ among treatments. The next spring, the seedlings were tested in two experiments. ( 1) The seedlings were transplanted into pots containing sandy soil in the greenhouse, where they were fertilized with either pure water or nutrient solution ( 22 mg N l(-1)). ( 2) The outplanting performance of the autumn-fertilized seedlings was tested on a sandy field. In the greenhouse experiment, the autumn fertilization level affected height growth and root egress of the seedlings significantly, but less than fertilization with a nutrient solution after planting. In the field experiment, during the first season after transplanting shoot growth of the seedlings increased with the level of autumn fertilization. After the second and third seasons, the seedling stem volume was highest with the highest level of autumn fertilization. These results suggest that, by improving the preplanting nutrient status of seedlings, the growth of shoot, stem diameter and root biomass can be enhanced after planting, especially on nutrient-poor soils. However, heavier autumn fertilization than that used here may yield a greater and more persistent increment in growth.