A global approach to mineral nutrition based on the growth needs of seedlings produced in forest tree nurseries

The nutrition of seedlings is a constant preoccupation for nurserymen. They must regularly define and adjust their fertilization schedules in relation to the species, age, and seedling phenology. They must also take account of the quality of the environment. In the approach described in this paper, the decision to fertilize is a function of the weekly growth needs of seedlings for N, P and K evaluated from the seasonal progression of seedling dry weight and nutrient tissue concentrations as well as the need to maintain substrate fertility. The dose of applied fertilizer takes into account the utilization percentage of NPK, the percentage efficiency of irrigation, the substrate density and volume as well as the fertilizer available. It also considers the area to fertilize and the characteristics of the equipment. During the season, the producer can modify his fertilization schedules as a result of the verifications carried out in the nursery and thus can act at the appropriate time. With the help of the computerized system PLANTEC, this approach is used in the nurseries of the Ministere des forets du Quebec (MFO).