Pecan trees benefit from a regular fertilization regimen to ensure healthy branch growth and good nut harvests. According to the University of Arkansas, nitrogen and zinc are the two most critical nutrients for pecan trees with several other macro and micro nutrients being drawn from the soil. Soil tests are helpful to determine what is lacking in the soil, if you are in any doubt about the qualities inherent in your planting soil.
Refrain from feeding pecan trees until their second year. Feed the trees in their second year and thereafter, two to three times each year from bud swell in early spring through early summer.
Apply a nitrogen fertilizer with a guaranteed analysis of 30-0-0 using 1/4 to 1/2-pound of fertilizer for every 100 square feet of soil surface around the pecan tree plantings.
Divide the total amount of recommended fertilizer for the area for the year, by the two or three feeding sessions in spring and early summer.
Scatter the fertilizer evenly around the base of the tree in a wide doughnut shape. Keep the fertilizer at least a foot and up to 2 feet from the trunk, extending to a foot past the drip line of the tree. Do not exceed the recommended amount of nitrogen fertilizer. While important to nut development, too much nitrogen can easily cause nut harvests to diminish.
Amend acidic growing soil, with a pH of 6 or less, with a 1/2-pound of zinc sulfate for every year of the trees age up to a maximum of 10 pounds per year. Make this amendment each year in the spring. Apply around the base of the tree out from the trunk and extending to just past the drip line.
Spray pecan trees growing in alkaline soil, above 7 pH, with a zinc sulfate foliar product. Dilute with water according to the product label directions but do not exceed 2-pounds of zinc sulfate for every 100 gallons of water. Spray your pecan trees with the solution three times in spring to coat the new branch, twig, stem and leaf growth.
Water in soil applied fertilizer well with each application. Drench the soil to a depth of at least a foot to leach the nutrients down into the root zone. Make the soil wet but not soupily so, where water has pooled on the surface.