Pecan Orchard Management
It is important to carefully consider several factors when establishing an orchard. Pecan trees are long-lived, decisions made during orchard establishment will affect production and management for at least several decades.
Pecan trees should be planted far enough apart to prevent crowding. Crowding can cause excessive shading of trees and decrease production (Wells et al., 2011). In California traditional pecan orchards contain approximately 50 trees per acre: at 35 x 25 ft (49 trees/ac) or 30 x 30 ft (48 trees/ac) spacing. Orchard design should also allow proper pollination (Wells, 2012). In California, one or two pollinator cultivars are typically planted every fifth row. For example, an orchard could contain four rows of Wichita, one row of Western Schley, four rows of Wichita and then one row of Pawnee. Orchard design (i.e. square, offset, equilateral triangle etc.) should also take into consideration cultural management practices including harvest operations.
Water management is one of the most important factors in pecan production. Current season’s vegetative growth (where the subsequent crop will be produced), nut size, and kernel quality (including percentage kernel and kernel color) are all significantly influenced by water management. Fully canopied pecan orchards require 40+ acre inches of water per year (from either rainfall or supplemental irrigation) to grow and produce well. Nut growth begins after pollination and extends through shell hardening (May to August), approximately 90 days after pollination. Nut filling, in which the kernel develops and fills out, also requires about 90 days, and occurs between August to October, depending on the cultivar.
Nut fill is influenced by many factors other than water, including: crop size, leaf conditions, nut size, size of the crop produced the year before, insects and diseases, weather conditions, and cross pollination (Byford, 2010).