Interfering limbs of alternating (temporary) `Elliott' pecan trees were pruned annually to provide growth for limbs of permanent trees for a 6-year period. Yield, nut quality, and tree growth were similar for pruned and nonpruned plots, but there were year × pruning interactions. Yields of the permanent trees were not affected by pruning the adjacent temporary tree.
Yield and quality of pecan nuts were as high when 50 pounds N/acre was applied through a dripirrigation system as with 100 pounds/acre (112 kg·ha−1) applied either all broadcast or half broadcast-half fertigated. All N treatments kept leaf N well above the 2.50% (dry weight) lower threshold recommended for pecans. The 50 pounds N/acre-all-fertigated treatment resulted in less soil pH reduction and less loss of K, Ca, and Mg from soil in the nonwetted zone underneath the tree canopy than broadcast treatments. Soil pH, K, and Mg were slightly lowered in the 6- to 12-inch (15 to 30 cm) soil layer when all of the N was fertigated. Higher leaf Ca and Mg from the low rate of N fertigated reflected the higher concentrations of these elements in the soil in the nonwetted zone rather than the lower concentrations in the wetted zone. There was no evidence of a detrimental effect on the tree from lowering the N application to only 50 pounds/acre and applying it in four monthly applications through the drip irrigation system beginning 1 Apr.
Fifteen pecan (Carya illinoinensis) genotypes were evaluated over a period of 20 years in a test orchard located near Tifton, Ga. Genotypes tested included seedling selections (`Candy', `Maramec', `Melrose', `Moreland', `Sumner', and `Western Schley'), USDA releases (`Creek', `Kanza', `Kiowa', and `Pawnee'), and USDA selections (USDA 41-19-20, USDA 53-11-139, USDA 53-9-1, USDA 57-7-22, and USDA 64-11-17). Actual yields were measured for each tree in the test throughout the test period and the alternate bearing intensity (I) of each cultivar was calculated. Average annual nut production in years 1 to 10 ranged from 19 lb (8.6 kg) in the precocious cultivar `Candy' to 6 lb (2.7 kg) in the nonprecocious cultivar `Melrose'. Although a wide variation was seen in the average yield of clones in years 11 to 20, differences were not significant. A subsample of nuts was taken for each tree annually and percent kernel, nuts/lb, specific gravity, and nut volume were determined. Significant differences were found between clones for each of these traits. Most clones were not acceptable for commercial use in Georgia due to small nut size, poor kernel quality, or excessive alternate bearing. Recommended clones include: `Pawnee', which produced large nuts of excellent quality with an early harvest date, `Sumner', which produced large nuts of moderate quality with a late harvest date, and `Kiowa', a precocious bearer of large, good-quality nuts.