Result Demonstration/Applied Research Report

2007 Howard County

Cotton Harvest Aid Demonstration

Cooperator: U.S.D.A. - A.R.S. at Big Spring, Texas

Tommy Yeater, Howard County Extension Agent - Agriculture

Dr. Billy Warrick, Extension Agronomist (San Angelo, Texas)

Summary

    Twelve treatments were applied over the top of cotton on September 26 to prepare for harvest. The plot was established on U.S.D.A. - A.R.S. farm located on the north side of Big Spring, Texas. The chemicals were applied to Field number 1, FiberMax 9063 cotton that had 85 percent of its bolls open. Leaf shed was less than one percent when the plot was established. When these plots were evaluated on October 4, 2007 (8 days after the treatments were applied), most of the treatments resulted in an increase in open bolls, leaf defoliation and leaf desiccation.

Objective

     On the east side of the Trans-Pecos Region 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:           U.S.D.A. - A.R.S. at Big Spring

Location:                                            North side of Big Spring, Texas

Crop Production Information:

            Variety Planted:                      FM 9063 

            Planting Pattern:                     Solid 

            Irrigation:                               None 

Harvest Aid Application Information:

            Date Applied:                         September 26, 2007

            Wind Speed:                           5.0 to 8.0 miles per hour

            Wind Direction:                      Southeast

            Air Temperature:                    83 to 87⁰ Fahrenheit

            Relative Humidity:                   38 to 49%

            Carrier:                                   18.0 gallons of water per acre

            Pressure:                                 34 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:                         32 inches

            Cotton Height:                        26 inches

            Ground Speed:                       4.0 miles per hour

            Application Device:                Self propelled rig with 13.33 foot boom

            Plot Size:                                13.33 feet X 60 feet

            Test Design:                           randomized block design replicated three times

Plant Information

     At the time of application, the upper most cotton bolls were cross-sectioned and several of the upper bolls were still immature. Cotton height ranged from 26 to 28 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 85 percent open all bolls on the plant were ready for harvest aids to be applied. The application of the harvest aids did impact boll opening, percent defoliation and percent desiccation. Several factors contributed to the success of the harvest aids applied, these include: 1) Chemical coverage was excellent due to gallonage, pressure used, and wind; and 2) Air temperatures for the 8 days after application were warm enough to allow for good cotton plant response. Leaf defoliation was higher than the check in all treatments and ranged from 35 to 89 percent on October 4, 2007 (8 days after the treatments were applied). None of the regrowth was high enough to be a concern. The data collected on October 4 is reported in Table 1.

Table 1. Howard County Cotton Harvest Aid Test, USDA-ARS at Big Spring

October 4, 2007 (8 days after treatments were applied)

      NOTE:   In Table 1 the individual or combination of letter a, b, c, or d beside the number are to indicate statistical significance. There is no statistical difference between numbers that have the same letter (even when there appears to be a large difference in results between the materials applied).

     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.

     When these plots were evaluated on October 4, 2007 (8 days after the treatments were applied), most of the treatments applied had a significant difference in boll opening, leaf defoliation and leaf desiccation. No regrowth had developed enough to be a concern at harvest time. However, some of the materials applied are known to be better at desiccating or removing juvenile growth. These include Aim, Blizzard, ET, and Ginstar. Please note that a crop oil concentrate was used in tank mixes that contained Aim, Blizzard, and ET; for maximum performance with these products, that is an important part of the tank mix.

     On October 4 the boll opening ranged from 95 to 98 percent. Increased boll opening was noted in all plots where harvest aids were applied.

      On October 4 the amount of leaf defoliation combined with leaf desiccation resulted in several of these plots being ready to harvest. The biggest concern in the test plot was the amount of leaves remaining on the plant where Gramoxone Inteon or Firestorm where applied. Having more than 30 percent of the desiccated leaves remaining on the plant may result in a higher amount of leaf in the ginned sample. Most years the gins in our area do a good job of removing the leaves, with the ginned samples ranging between 2 and 4. In several treatments a followup application of a desiccant would have prepared the field for harvest with very few leaves remaining.

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. Several of the treatments were in the 10 dollar per acre range and the use 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

I want to take this opportunity to thank U.S.D.A. - A.R.S. at Big Springs for their help in plot establishment and management.

I would also like to thank the companies that provided the chemicals for this harvest aid test. These include:

            - Bayer CropScience who provided the Finish 6 Pro, Ginstar, and Prep

            - Chemtura who provided the Blizzard and Firestorm

            - DuPont who provided the FirstPick

            - FMC Corporation who provided the Aim

            - Helena Chemical Company who provided the N.I.S. (Induce)

            - Nichino America who provided the ET

            - Syngenta Crop Protection, Inc. who provided the Gramoxone Inteon

- Tri-State Chemical (UAP) who provided the C.O.C. (Herbimax)