Result Demonstration/Applied Research Report

2007 Runnels County

Cotton Harvest Aid Demonstration

Cooperator: Paul Minzenmayer

Rick Minzenmayer - IPM for Runnels and Tom Green Counties

Marty Gibbs, Runnels County Extension Agent - Agriculture

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

Summary

    Twelve treatments were applied over the top of cotton on September 27 to prepare for harvest. The plot was established on Paul Minzenmayer’s Farm located 6 miles north of Ballinger, Texas. The chemicals were applied to Deltapine 143 B2F cotton that had 70 percent of its bolls open. Leaf shed was less than one percent when the plot was established. When these plots were evaluated on October 10, 2007 (13days after the treatments were applied), most of the treatments resulted in an increase in open bolls, leaf defoliation, and leaf desiccation. Regrowth was not a problem in most of the plots and none of the regrown to the point where it would interfere with harvest.

Objective

     In the Southern Rolling Plains, 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:           Paul Minzenmayer

Location:                                            5 miles south of Ballinger, Texas

Crop Production Information:

            Variety Planted:                     Deltapine 143 B2F

            Planting Date:                        May 23, 2007

            Planting Rate:                        33,000 seeds/acre

            Planting Pattern:                     Planted solid on 40 inch rows

            Irrigation:                               No irrigation available

            Number of Irrigations:            None

Harvest Aid Application Information: 

            Date Applied:                         September 27, 2007

            Wind Speed:                          1.0 to 4.0 miles per hour

            Wind Direction:                      Southwest

            Air Temperature:                    75 to 87⁰ Fahrenheit

            Relative Humidity:                   53 to 80%

            Carrier:                                   16.0 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:                          36 inches

            Cotton Height:                         30 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 four times

Plant Information

     At the time of application, the upper most cotton bolls were cross-sectioned, the seed coats were dark, and the cotyledons well developed. Cotton height averaged 30 inches and 70 percent of the bolls were open. Plants had regrowth in the top and bottom portion of the plants . Leaf defoliation was less than one percent.

Results and Discussion

   The cotton at the time of application was 70 percent open with most of the remaining bolls being mature. 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) The cotton was mature; 2) Chemical coverage was excellent due to gallonage, pressure used, and wind; 3) Day and night air temperatures for the 13 days after application were warm. Leaf defoliation was higher than the check in all treatments and the increase ranged from 6 to 11 percent on October 10, 2007 (13 days after the treatments were applied). The removal of leaves usually results in rapid development of the juvenile leaves, however, several of the harvest aids used in this plot dessicate or remove regrowth. In this test, Ginstar when used above four ounces per acre removed regrowth and Aim, Blizzard, and ET desiccated regrowth. The data collected on October 10 is reported in Table 1.

Table 1. Runnels County Cotton Harvest Aid Test (Paul Minzenmayer Farm, 2007)
October 10, 2007 (13 days after treatments were applied)
(NOTE: Linked to each harvest aid treatment is a picture of the plot)

      NOTE:       In Table 1 the individual or combination of letter a, b, c, d, e, or f shown 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). Also, to account for 100 percent of the leaves you would add the percent defoliation plus the percent dessication and subtract from 100. The difference represents the number of original green leaves still remaining on the plant.

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

Increased boll opening was noted in all plots where harvest aids were applied with boll opening ranging from 97 to 99 percent. All plots had more leaf defoliation than the check. The plots where paraquat was applied as Gramoxone Inteon or Firestorm had leaf desiccation level high enough to be a concern. The leaf desiccation levels in the paraquat plots ranged from 26 to 46 percent and could result in leaf grades above 3 when ginned.

Eight of the treatments had less than 5 percent green leaves and would be harvestable if it could be ginned within 24 hours of harvest. To dessicate the remaining leaves in the test a followup application of paraquat was applied.

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 6 to 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 Paul Minzenmayer for his help in plot establishment and management. Also a word of thanks to Pam Halfmann for her help in plot establishment.

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

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

            - Chemtura who provided the Blizzard and Firestorm

            - FMC Corporation who provided the Aim

            - Nichino America who provided the ET

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

- Tri-State Chemical DBA United Agra Products (UAP) who provided the C.O.C. (Herbimax)