1) If it is already planted, you options are limited. There are some "stick the garden hose into it" and then " water the root area type tree and plant fertilizers that work OK. Those large plant and tree "spikes" don't work very well, especially if you live in an area that only has seasonal rainfall. You could dig down no closer than 12" (depending on the size of the tree--if it's older than 5 years--you might damage the root system) with a hand trowel and bury a mixture of soil and animal fertilizer three in a triangle shape outside the planter in the center would work.
2) If the tree is not already planted...in the subsoil, dig down about 2 feet and dig a hole 2 feet in diameter. With the soil you have removed, keep half. Refill the hole, mixing it half and half with either cow, horse, sheep, or even duck fertilizer. Plant the tree in that.
Pine trees have very shallow root systems compared to how tall they eventually get. They are actually pretty forgiving about their sunlight.
If you try to use commercially made "lawn/garden" fertilizers like for use in spreaders it just might kill the tree.
ROX