Fifty Years With Texas Pecans
Tree Spacing: The Hugo Pape pecan production demonstration at Seguin, Texas, taught us pecan spacing is critical. This test started great and ended terribly. A 10-acre block with a close spacing of 30-by-30 feet without tree thinning or mechanical hedging ended after 12 years with zero production for at least four years following. We later learned a 35-by-35 foot spacing in Central and East Texas could go much longer than 12 years without overcrowding crop loss. Also, in the West where hedging is now standard practice, wider 42-by-42-foot spacing is being used with good results. Hal Berdoll at Bastrop tested close-spaced trees as well but soon learned space makes money.
Varieties: My first speech on pecans was at Gonzales, Texas, in October 1969 and my topic was varieties. Mr. Hancock drove, while I took notes on the Texas A&M recommended varieties at the time. Number one was ‘Desirable,’ which it still is today. The new USDA varieties at that time were the center of attention; however, over time, ‘Desirable’ consistently outyielded all varieties with sustained kernel quality as older trees. Texas Pecan Shows served as a selection tool for the entire industry and either moved cultivars forward or rejected them faster than any other formal system. Texas pecan variety trial demonstrations were conducted in every region of the state with positive and negative differences in full view side by side. ‘Desirable’ led in the East, and ‘Western’ was the leader in the West. ‘Wichita’ gave high quality and yield but demanded maximum management. ‘Sioux’ and ‘Pawnee’ also proved to be good commercial varieties. ‘Cheyenne’ was a superstar when young but failed at age 12. Most of all new varieties look good as young trees, but to be outstanding, those varieties must be judged over 15 years to learn if one bears every year with good quality. And there are only a very few varieties that can. I had a 16-year test plot with ‘Choctaw’ that produced 4,000 pounds in the eighth year, but the trees could not sustain production without alternate bearing and poor quality, thus failing the long-term test.
Soil: Mr. Hancock was a big advocate of deep, well-drained soil. We have estimated Texas to have over 100,000 acres of improved pecans, but too many of these acres do not bear because they are planted on shallow soil or poorly drained clay soil. Internal soil drainage creates air available for young roots to stay alive, absorb water, and absorb nutrients. This drainage is not surface drainage or runoff; it is water moving down and out of 32 inches of soil—fast. Our simple 8-by-32-inch drainage test hole needs to be empty in one hour for maximum yields or empty in 24 hours for commercial profits. All slow or poorly drained soils should not be planted with pecans.
Zinc Foliar Sprays: Zinc is a big deal in pecans, and we tested it with Hugo Pape, George Koch, and Thurman Gibson. Acid or alkaline soil can contain high levels of zinc, but pecans have difficulty absorbing it. Indole-3-acetic acid (IAA) is the most important growth hormone in plants and pecans; without zinc in the leaves, IAA is not produced, and the shoots and leaves grow short and small. Zinc foliar sprays, such as zinc sulfate or zinc nitrate, need to cover the foliage five times each spring to obtain optimum growth. In 1969, we were spraying only once; today we know five times is ideal. Hal Berdoll was the first to show spraying young trees with zinc every week plus frequent small applications of nitrogen and drip irrigation could bring an orchard into commercial production in only five years.
Nitrogen Soil Fertilizer: Nitrogen is the only major element needed on pecans in Texas. Three soil-applied applications will create good shoot growth and nut production. Phosphorus and potassium are available in most Texas soils at a high or adequate level. East Texas’ shallow acidic soils are the only exception to this rule. Nitrogen is applied as foliar sprays and soil-applied fertilizer. Pecan fertilizer tests with Hal Berdoll at Bastrop, Thurman Gipson at Palestine, and Hugo Pape at Seguin showed that 100 pounds of ammonium nitrate or urea per acre applied in May, June, and July were essential for obtaining strong growth, large leaves, kernel filling, and late-season leaf retention. Orchards in decline or with a heavy crop need more. Also, trees with no crop should not be fertilized as it stimulates excess vegetative growth, which contributes to alternate bearing.
Integrated Pest Management (IPM): Controlling or reducing insects and diseases is a crucial part of pecan production. Dr. Perry Adkisson, chair of the Texas A&M Department of Entomology from 1967-1978, guided many crop specialists for years with one major objective: spray only as needed. Texas producers contend with pecan nut casebearer, while eastern growers deal with scab. Both demand growers’ full knowledge and ability to respond to and treat; otherwise, the crop can be lost.
These lessons make up a few of the most important that I learned over my 51 years with Texas pecans. Though only a few, these practices remain essential to consistently producing a quality crop. Next month, I will share more of the lessons I learned over the years while working with pecan researchers and growers.