What is in this article?:
- Production efficiencies vital to Arizona pecan growersâ€™ bottom lines
- N, zinc key ingredients
- Aphids a 2014 threat?
- Water, nutrition, alternate bearing, and aphids are among the front-burner issues for Arizona pecan growers striving to produce a high quality with good yields.
N, zinc key ingredients
Kilby says nitrogen and zinc are the primary nutrients for a good pecan crop. About 180-250 pounds of N is added each season.
Zinc is traditionally applied as a foliar spray. Kilby shared encouraging news which could change future zinc applications. He says UA soil scientist Jim Walworth has found great success in trials applying chelated zinc through drip and sprinkler irrigations.
Kilby said, “This method could be more efficient and effective for the grower. The application process could reduce the amount of the zinc actually needed by the trees and save spraying costs.”
About 60 percent of the commercial pecan trees in Arizona are the Western Schley variety. The balance is the Wichita variety. In an effort to help capture part of the growing U.S. pecan export market to China, some Arizona growers are planting the Pawnee variety, a larger nut harvested earlier in the season and preferred by Chinese consumers.
The most popular pecan tree spacing is 20 feet between the trees and 40 feet between the rows (20-by-40). Some newer plantings are 30-by-30 feet.
Pecans are an alternate-bearing crop where the tree produces a larger crop one year followed by a smaller crop the next year. Yields can fluctuate up to 30 percent between the on-off years in Arizona.
Many growers want to reduce the yield difference in back-to-back years. Kilby says reducing alternate bearing can improve long-term tree health.
“Currently in the on-year, pecan trees are drained of carbohydrates. Reducing the alternate-bearing swing could help balance overall tree health from year to year,” said Kilby.
The top methods growers use to minimize alternate bearing include tree pruning and nut thinning.
“Pruning helps to reduce the tree size and opens up the tree to increased photosynthesis which can improve nut yield and quality,” Kilby said.
Most pruning is done mechanically which Kilby says can be faster, more economical, and safer for workers versus climbing ladders high into the trees.
Fruit thinning generally occurs in August during the ‘on year.’ Thinning is especially effective in the Wichita variety.
“The pecan industry will never eliminate alternate bearing 100 percent,” Kilby said. “The industry will always have some yield variation from year to year.”
Kilby also discussed the importance of improved root development by ripping the soil. He recommends that growers rip the ground every three to four years and add gypsum as a soil amendment. The gypsum helps remove the buildup of sodium and salt in the soil.