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Pesticide and Defoliant Reduction in Cotton Using Thermal Cultivation

Dan Kelly, Director
Railroad Commission of Texas
Alternative Fuels Research and Education Division
PO Box 12967
Austin, Texas 78711-2967
512-463-7291
512-463-7292 (fax)
dan.kellvrrc.state.tx.us

Purpose Statement

Thermal defoliation of cotton (as an alternative method to prepare the crop for harvest) eliminates water and air pollution caused by harvest-aid chemicals, reduces the need for insecticides, protects the crop from insect sugar deposits and is independent of the weather.

Project Duration: 10 months

Funding Request
Budget Category Funding Requested Matching Non-Federal Funds Matching
Federal Funds
First Year Funding
$47,000
0
0
Second Year Funding
0
0
0
Total Funding
$47,000
0
0

Executive Summary

The Texas Railroad Commission (RRC), through its Alternative Fuels Research & Education Division (AFRED), seeks $47,000 from the EPA for a project that offers to reduce the health and environmental risks associated with the use of chemical defoliants and insecticides in cotton, by demonstrating and evaluating the effectiveness of thermal crop cultivation technology.

Interest in thermal defoliation has rekindled with the increase in organic cotton production, since producers of organic cotton are restricted from using harvest-aid chemicals and pesticides. One benefit arising from thermal defoliation includes control of the late-season sucking insects responsible for “sticky cotton.” The primary insect pests that cause sticky cotton and degrade the quality of the lint are the cotton aphid and the silverleafwhitefly. The cotton aphid secretes honeydew on exposed lint in open boIls, which causes the lint to become very sticky and results in severe problems during ginning and spinning processes at textile mills. If sticky lint is detected, the price of the lint is reduced; in severe cases, the lint may be rejected entirely by the gin or the mills. Sticky lint, caused in part by cotton aphids, was serious in west Texas in 1995, and the threat of this problem to cotton production has been persistent ever since.

The proposed project will help demonstrate that thermal defoliation of cotton is an effective means for organic cotton producers to terminate their crop for timely harvest, while reducing fiber quality degradation, without using chemicals or pesticides.

The planned work builds on initial trials managed by the RRC/AFRED in cooperation with the Propane Education & Research Council, the Texas A&M University System AREC, and the U.S. Department of Agriculture’s Southwestern Cotton Ginning Laboratory. This initial field work has shown that thermal defoliation results in greater leaf kill and less leaf drop as compared to standard harvest-aid chemical treatments. Funds are requested from EPA for additional modifications to the prototype implement, field trials and environmental impact analyses on the use of thermal cultivation technology. The field tests will be conducted during the 2006 harvest season in the Lower Rio Grande Valley of Texas, a main cotton-producing region. The tests will compare the cost and effectiveness of thermal defoliation to conventional chemical defoliation and the effectiveness of thermal defoliation in reducing sticky cotton. If additional funds become available, additional field trials may be conducted in the Brazos Valley of Central Texas and/or the High Plains of Texas, where organic cotton is grown.

Objectives

Rationale

Effectiveness

The project will quantify the effectiveness of thermal defoliation with respect to leaf desiccation, inhibition of troublesome plant re-growth, and late-season insect control. Texas cotton fields are prone to late-season insect damage, and sticky cotton caused by insect honeydew leads to increased chemical control and processing costs. Thermal defoliation may hold particular benefits for late-season cotton, as heavy leaf canopies inhibit effective applications of pesticides. Lint quality will be analyzed and compared under the two defoliant regimes.

Environmental benefits

Chemical defoliation affects water quality and air quality. The reduction in chemical treatments using thermal defoliation is expected to produce direct and indirect environmental, human health, and pollution prevention benefits. Chemical defoliants typically contain reactive organic compounds that lead to increased air pollution, and air regulations increasingly aim to reduce volatiles used in chemical pesticides, defoliants, and harvest-aid materials. Propane fuel used to produce defoliating heat will not contaminate groundwater or soils, and propane combustion emissions during defoliation are inherently low in ambient air criteria pollutants listed under the federal Clean Air Act.

Cost analysis. The project will help determine optimal thermal treatment regimes required to protect lint quality. Material and labor costs of thermal defoliation using the second-generation commercial prototype will be recorded and compared to the well-established time and cost requirements of conventional defoliation.

Approach and Methods

A test-bed thermal defoliator was built in 2003 and field-tested in Texas, New Mexico and California in 2004 by the USDA. A second-generation prototype was developed and built in 2005 by Agricultural Industrial Manufacturing (AIM), 110 S. Beckman Road, Lodi, California, under a $323,000 grant from the Propane Education & Research Council (PERC). This unit will be modified based on additional 2005 field trials and used on cotton during the 2006 growing season. When these modifications are complete, the unit will be available for additional field testing in Texas.

The proposed scope of work includes:

  1. Make the prototype defoliator ready for testing; modifications and repairs will be carried out by the builder of the unit, Claude Brown.
  2. Transport the unit from California to the Texas A&M University System agricultural research center in Weslaco, Texas. Conduct tests on 8 test blocks and compare results with those achieved on 8 control blocks using conventional chemical practices.
  3. There are about 10,000 acres of organic cotton in Texas. If additional funds become available, enter into a cooperative agreement with an organic cotton producer on the Texas High Plains to defoliate approximately 100 acres of commercial organic cotton.

Planned field research will include:

Background Information

Organic cotton production precludes the use of pesticides and harvest-aid chemicals, thereby requiring alternative methods of preparing the crop for harvest. Thermal defoliation accomplishes this by using heated air to raise the leaf temperature enough to cook the plant’s cells, drying the leaves and causing them to fall. The process eliminates the need for a second pass over fields for newly formed fiber. It also destroys the pests most responsible for causing sticky cotton. By contrast, conventional chemicals and pesticides require time and favorable weather conditions to be effective (Logan and Gwathmey, 2002). Additionally, these chemicals do not protect the crop from insect sugar deposits. Propane-fueled thermal defoliation not only facilitates organic production, but may prove helpful when a conventional cotton crop is threatened by bad weather or late season sucking insects.

Harvest timing treatments were evaluated in 2003 and 2004 to quantify the effects of early harvest on yield and fiber quality. Because the near-immediate and total destruction of green leaves might also drive away late season sucking insects responsible for sticky cotton, thermal defoliation treatments were included in a University of California study combining harvest-aid chemicals with insecticides.

Thermal defoliation studies were conducted with a tractor-towed one-row experimental thermal defoliator for two seasons, to prove the concept and to quantify crop response to various combinations of speed and temperature. Fiber and yarn quality for both thermal and conventional harvest preparation was measured in 2002. Slightly higher fiber values from better leaf and color grades were found with thermal defoliation (Funk et at, 2004a). Based on these initial studies, a self-propelled two-row prototype thermal defoliator was constructed to quantify field efficiencies and fuel consumption (Funk et at, 2004b).

This project witnessed eight successful trials in three states in 2004. Resources for this project have been provided by the USDA Agricultural Research Service, the Propane Education & Research Council (PERC), and the University of California Shafter Research and Extension Center.

Resources

The Alternative Fuels Research and Education Division of the Texas Railroad Commission (RRC) will manage this project in coordination with the Texas A&M University System’s Agricultural Experiment Station in Weslaco, TX. The Railroad Commission is Texas’ chief energy agency, responsible for regulation of oil and gas, pipeline safety, surface mining, and liquefied petroleum gas. Both the RRC and TAMUS-AREC will work in close consultation with Dr. Paul Funk of the USDA-ARS Southwestern Cotton Ginning Research Laboratory in Mesilla Park, New Mexico. Dr. Funk currently serves as principal investigator of an ongoing multi-state thermal cotton defoliation initiative.

The project team will also consult closely with the PERC Agriculture Advisory Committee, a volunteer body of 17 government, propane industry, and agricultural experts. Earlier this year, PERC contributed an additional $180000 to the redesign of the thermal defoliation program, and its active agricultural advisory board remains keenly interested in technology transfer and the widespread adoption of this environmentally beneficial alternative to pesticides and chemicals.

Measures and Outcomes

“What will be different as a result of this project?” Thermal defoliation of cotton holds substantial potential to reduce current reliance on chemical defoliants, a goal embraced by the Pesticide Environmental Stewardship Program (PESP). Critical operational and cost parameters of thermal defoliation are not well known, however, and are therefore primary targets for research under this proposed project. Thermal defoliation may offer a steady, ready, reliable, portable, and environmentally superior option for control of troublesome insects and plant structures in cotton production. Reducing pesticide and herbicide use with a cost-effective thermal defoliator should lead to direct and indirect environmental benefits to water, soil, and air quality resources, while bolstering federal, state, and local programs aimed at reducing environmental and human exposures to toxic or hazardous pesticides and herbicides. This project’s comparative study of important functional parameters between chemical and thermal defoliation regimes will yield objective, quantitative information that may then form the basis for future actions or decisions undertaken by agriculturists or agriculture agencies.

Outreach

PERC will commence a communication and outreach program through the print and electronic media that will increase awareness of the propane-fueled apparatus among producers and other stakeholders. This communications program is vital to build awareness of this project in particular and of the role the Propane Council will continue to play in creating new opportunities in the Integrated Pest Management (1PM) community through new product research, development, demonstration, commercialization, and marketing of environmentally beneficial agricultural technologies. The intended audience will include cotton producers, academia, the Sustainable Cotton Project, the Chile Pepper Task Force, organic growers’ associations, cotton ginning and cotton growers’ associations, the federal government (including the USDA and the 1PM Program), and the propane industry.

PERC (est. 1996) enjoys nationwide stature in its ability to showcase the commodity and reach out to literally millions of consumers through various media. Consumer traffic on www.useproQane.com more than tripled in 2004, with more than 100,000 searches of the Find a Propane Retailerfeature of the site. Propane kicked off the 2005 television campaign on February 20 with a presence in the Daytona 500 on the FOX broadcast network. The TV campaign will continue with other NASCAR events on NBC as well as on cable networks including HGTV, The Weather Channel, and Country Music Television. Wide-ranging radio, online, and print advertising will round out the 2005 campaign.

Sustainability

This project will help to demonstrate the feasibility of the thermal cultivation concept to a wider audience. We believe that this application is also useful for chile pepper crops as an alternative to salt defoliation (which reduces soil fertility). The results of thermal cultivation field trials will be made available to the Chile Pepper Task Force, a regional collaboration of growers, processors, scientists, and manufacturers working to realize a system-wide development of technological advances required for harvest mechanization (www chiletaskforce.orcfl. Results could also be valuable for chemical-sensitive crops planted near cotton fields, such as citrus or lettuce.

PERC is an important and logical project partner and is committed to continuing its assistance through the contribution of both resources and collaboration (especially in the 1PM and EPA Pesticide Environmental Stewardship Programs). The purpose of PERC is to promote the safe, efficient use of propane as a preferred energy source. With the enactment of the Propane Education and Research Act in 1996, PERC began receiving funding by an assessment or “check-off’ on each gallon of odorized propane gas sold in the U.S. Each dollar of the collected assessment funding is used to fund innovative programs and projects such as the thermal crop cultivation effort.

Literature Cited

Timetable

Major Participants

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