Result Demonstration/Applied Research Report

2004 Runnels County

Cotton Harvest Aid Demonstration

Cooperator: Mark Jacob

Summary

    Twelve treatments were applied over the top of cotton on September 14 to prepare for harvest. The plot was established on Mark Jacob’s Farm located 5 mile south of Winters, Texas. The chemicals were applied to Associated Farmers Delinting AFD3511 cotton that had 50 to 60 percent of its bolls open. Leaf shed was less than one percent when the plot was established. When these plots were evaluated on September 23, 2004 (9 days after the treatments were applied), most of the treatments resulted in an increase in leaf defoliation and leaf desiccation.

Objective

     In the Concho Valley Area of Texas, cotton is usually planted starting in mid-May. Because of this planting date, many producers do not use harvest aids to terminate the cotton. When growing conditions are favorable, most of the cotton in this area is ready for harvest thirty days before the first killing freeze. The delay in harvest reduces the income of farmers due to the loss of lint yield and fiber quality. Even though the cost of several of the harvest aid treatments are expensive, there is usually a product that is economically justified that can be used effectively for crop termination. The intent of this field test is to: 1) determine the effectiveness of harvest aids at defoliating, desiccating, and opening bolls on cotton 2) provide producers the opportunity of observing how effectively the harvest aid materials work, and 3) determine the economic feasibility of using the harvest aid material.

Materials and Methods

Cooperating County Producer:           Mark Jacob

Location:                                            5 miles south of Winters, Texas

Crop Production Information:

            Variety Planted:                     Associated Farmers Delinting AFD 3511

            Planting Pattern:                    2-in-1-out on 40 inch rows

            Irrigation:                               Dryland Production

            Number of Irrigations:            None

Harvest Aid Application Information: 

            Date Applied:                         September 14, 2004

            Wind Speed:                           5.0 to 7.0 miles per hour

            Wind Direction:                      South

            Air Temperature:                    80 to 86⁰ Fahrenheit

            Relative Humidity:                  50 to 65%

            Carrier:                                   16.5 gallons of water per acre

            Pressure:                                 32 pounds per square inch

            Nozzle Size:                           11002 extended range flat fan over the top of each row and one 8002 Extended Range nozzle on each side of the row.

            Boom Height:                         40 inches

            Cotton Height:                        26 to 34 inches

            Ground Speed:                        4.0 miles per hour

            Application Device:                Self propelled rig with 13.33 foot boom

            Plot Size:                                6.67 feet X 60 feet

            Test Design:                           randomized strip design

Plant Information

     At the time of application, the upper most cotton bolls were cross-sectioned and the seed coats were dark and the cotyledons well developed. Cotton height ranged from 26 to 34 inches. Plants showed no sign of stress and leaf defoliation was less than one percent.

Results and Discussion

  The cotton at the time of application was 50 to 60 percent open with most of the remaining bolls being mature. The application of the harvest aids did impact percent defoliation and percent desiccation. Factors that contributed to the success of the harvest aids applied were: 1) Chemical coverage was excellent due to gallonage, pressure used, and wind; 2) Air temperatures for the 10 days after application were warm enough to allow for good cotton plant response. Leaf defoliation was higher than the check in all treatments and the increase ranged from 11 to 81 percent on September 23, 2004 (9 days after the treatments were applied). Leaf desiccation was high in several plots where the Gramoxone Max rates were above 10 ounces. However, none of the desiccation was high enough to be a concern. The data collected on September 23 is reported in Table 1.

     Prior to making any application, the cotton plant was examined closely to determine if regrowth was occurring. Since most harvest aids are contact materials, nozzle type, nozzle configuration, volume of water applied and pressure are important considerations. One of the better nozzle arrangements was used in this plot. It consisted of one nozzle over the top of the row and drops in the furrows with one nozzle spraying each side of the plant. The volume of water and application pressure should be high enough to get good coverage on the top and bottom portion of the leaf and penetrate the canopy enough to properly cover the axilary and terminal buds, as well as the bolls.

     No regrowth was noted in the plot. However, some of the materials applied are known to be better at desiccating or removing juvenile growth. These include Ginstar, ET and Aim.

     Gramoxone Max is a harvest aid used by most dryland producers to terminate their crop. The effect of rate and type of tank additive were the focus of most of the treatments in the test. How these combinations compared to other harvest aids were also studied in this test. To get a moderate level of leaf defoliation, a minimum of eight ounces of material had to be applied. The 16 ounce rate of Gramoxone Max preformed well, whether it was combined with a surfactant (Activator 90) or the crop oil concentrate (Herbimax). Increased boll opening was noted in the plots where ethephon and Gramoxone Max were applied.

     Please note that a crop oil concentrate was used in tank mixes that contained ET or Aim. For maximum performance with these products that is an important part of the tank mix.

Economic Analysis

     This test can be used to document the results obtained from the use of harvest aids. If the same treatments are consistently at the top of the list for several years, then producers may want to incorporate those treatments into their cotton production program. Most of the treatments were in the 6 to 10 dollar per acre range and the use of several of these treatments should result in increased profits for producers. It is important to remember that a higher lint yield is not the only way of increasing profit from the use of a harvest aid. Other factors include: timely harvest, improved fiber quality, improved harvesting efficiency, and higher percent lint turnout at the gin.

Acknowledgments