Progress 09/01/02 to 08/31/06
Outputs
The impending phase-out of methyl bromide by the year 2005 has placed a needed emphasis for safe and reliable replacement alternatives to this product. One such chemical alternative is metam sodium, which quickly converts to a volatile chemical methyl-isothiocyanate (MITC). Conventional application methods for metam sodium are direct soil surface application via sprinkler units, soil injection, or surface sprayer application. Another application method that may be safer and more effective at controlling soil-borne pests is via use of drip irrigation lines, a process known as drip fumigation. Few studies have focused on comparing the field off-gassing potential of MITC when metam sodium is applied by direct soil injection, sprinkler application, and drip fumigation. These field studies were aimed at improving the understanding of soil MITC doses and its off-gassing rates relative to biological performance. The general objective of these field trials was to acquire data
on air quality, soil characteristics, meteorological conditions, and crop production in States currently using soil fumigation practices, like CA and FL. Field data on MITC soil-air and atmospheric release were collected from several field studies performed in September 2002 at Bakersfield, CA, March 2003 at Citra, FL, and February 2004 at Salinas, CA. Studies in California covered off-gassing emissions from a loamy-sand soil under metam sodium application via sprinkler overhead application vs. drip fumigation. Florida studies involved vegetable crop production evaluations after metam sodium application via direct soil injection vs. drip fumigation in a fine sandy soil. Tomato crop production in metam-sodium treated sandy Florida soil was compared to methyl bromide treated soil. Crop production from metam sodium treated sites was lower than methyl bromide treated sites due to poor nutsedge weed and root-knot nematode control. Volatilization loss of MITC from surrounding field sites
was monitored at each location and this data was used in conjunction with the EPA dispersion model ISCST3 to model the off-field exposure of potential MITC release into the atmosphere. Modeling work was performed by meteorologists located in Alexandria, Virginia. Laboratory studies with metam sodium were done at Texas A&M University-Kingsville, TX to simulate MITC volatilization from the soil profile using 60-cm steel columns. These lab tests evaluated the influence varying water application rates have on MITC retention in the soil-air phase and to simulate soil off-gassing when water is used as a potential soil seal to prevent and/or minimize MITC release into the atmosphere. Increasing surface application of water was found to significantly suppress MITC loss through the soil surface. Additional column studies evaluated Vapam and K-pam volatilization loss under varying soil conditions was also assessed. Increasing organic matter content in soils did not significantly reduce MITC
loss, whereas soil type had a greater influence on MITC distribution within the soil profile and its subsequent loss to the atmosphere.
Impacts
The potential benefit of this work will help determine whether application of metam-sodium followed by soil surface irrigation is a safe and reliable soil fumigant alternative protocol to replace methyl bromide. Findings from these studies will aid the USDA CSREES Methyl Bromide Transitions Program by its contributing to better and safer application methodologies for metam sodium as a replacement for methyl bromide. This work may assist growers and researchers in the potential transition from conventional soil injection of metam sodium to surface water seal and/or drip fumigant application methods. Results from this work can provide growers with necessary information on the chemical dispersion within the soil, MITC off-gassing potential, and an accurate pest control reliability assessment of metam-sodium when applied by various methods. The overall aim of this work was to provide evidence to support safer and more environmentally conscience soil fumigant application
methods. Results from field and laboratory studies provide evidence that water application to the soil after metam sodium application can reduce the amount of chemical release into the atmosphere. However, the reduction in chemical loss may not necessarily translate into an economic benefit to the the grower, as decreased crop yield were observed in Florida sandy soils that are characteristically high in pest pressures.
Publications
- S.D. Nelson, D.W. Dickson, H.A. Ajwa, and D.A. Sullivan. 2004. Efficacy of metam sodium under drip and surface spray application in Florida tomato production. Subtropical Plant Science. Journal of the Rio Grande Valley Horticultural Society. 56:16-20.
- Master of Science Thesis: Jerry E. Stratmann. May 2004.The Development of Metam Sodium Application Methods for Minimizing Volatilization. Texas A&M University-Kingsville. Major Advisor: S.D. Nelson.
- Master of Science Thesis: Catherine R. Simpson. Aug. 2005. Volatilization Loss of Vapam and K-pam in Different Soil Types and Varying Organic Matter Levels. Texas A&M University-Kingsville. Major Advisor: S.D. Nelson.
|
Progress 09/01/02 to 08/31/05
Outputs
The impending phase-out of methyl bromide by the year 2005 has placed a needed emphasis for safe and reliable replacement alternatives to this product. One such chemical alternative is metam sodium, which quickly converts to a volatile chemical methyl-isothiocyanate (MITC). Conventional application methods for metam sodium are direct soil surface application via sprinkler units, soil injection, or surface sprayer application. Another application method that may be safer and more effective at controlling soil-borne pests is via use of drip irrigation lines, a process known as drip fumigation. Few studies have focused on comparing the field off-gassing potential of MITC when metam sodium is applied by direct soil injection, sprinkler application, and drip fumigation. These field studies were aimed at improving the understanding of soil MITC doses and its off-gassing rates relative to biological performance. The general objective of these field trials was to acquire data
on air quality, soil characteristics, meteorological conditions, and crop production in States currently using soil fumigation practices, like CA and FL. Field data on MITC soil-air and atmospheric release were collected from several field studies performed in September 2002 at Bakersfield, CA, March 2003 at Citra, FL, and February 2004 at Salinas, CA. Studies in California covered off-gassing emissions from a loamy-sand soil under metam sodium application via sprinkler overhead application vs. drip fumigation. Florida studies involved vegetable crop production evaluations after metam sodium application via direct soil injection vs. drip fumigation in a fine sandy soil. Tomato crop production in metam-sodium treated sandy Florida soil was compared to methyl bromide treated soil. Crop production from metam sodium treated sites was lower than methyl bromide treated sites due to poor nutsedge weed and root-knot nematode control. Volatilization loss of MITC from surrounding field sites
was monitored at each location and this data was used in conjunction with the EPA dispersion model ISCST3 to model the off-field exposure of potential MITC release into the atmosphere. Modeling work was performed by meteorologists located in Alexandria, Virginia. Laboratory studies with metam sodium were done at Texas A&M University-Kingsville, TX to simulate MITC volatilization from the soil profile using 60-cm steel columns. These lab tests evaluated the influence varying water application rates have on MITC retention in the soil-air phase and to simulate soil off-gassing when water is used as a potential soil seal to prevent and/or minimize MITC release into the atmosphere. Increasing surface application of water was found to significantly suppress MITC loss through the soil surface. Additional column studies evaluated Vapam and K-pam volatilization loss under varying soil conditions was also assessed. Increasing organic matter content in soils did not significantly reduce MITC
loss, whereas soil type had a greater influence on MITC distribution within the soil profile and its subsequent loss to the atmosphere.
Impacts
The potential benefit of this work will help determine whether application of metam-sodium followed by soil surface irrigation is a safe and reliable soil fumigant alternative protocol to replace methyl bromide. Findings from these studies will aid the USDA CSREES Methyl Bromide Transitions Program by its contributing to better and safer application methodologies for metam sodium as a replacement for methyl bromide. This work may assist growers and researchers in the potential transition from conventional soil injection of metam sodium to surface water seal and/or drip fumigant application methods. Results from this work can provide growers with necessary information on the chemical dispersion within the soil, MITC off-gassing potential, and an accurate pest control reliability assessment of metam-sodium when applied by various methods. The overall aim of this work was to provide evidence to support safer and more environmentally conscience soil fumigant application
methods. Results from field and laboratory studies provide evidence that water application to the soil after metam sodium application can reduce the amount of chemical release into the atmosphere. However, the reduction in chemical loss may not necessarily translate into an economic benefit to the the grower, as decreased crop yield were observed in Florida sandy soils that are characteristically high in pest pressures.
Publications
- S.D. Nelson, D.W. Dickson, H.A. Ajwa, and D.A. Sullivan. 2004. Efficacy of metam sodium under drip and surface spray application in Florida tomato production. Subtropical Plant Science. Journal of the Rio Grande Valley Horticultural Society. 56:16-20.
- Master of Science Thesis: Jerry E. Stratmann. May 2004.The Development of Metam Sodium Application Methods for Minimizing Volatilization. Texas A&M University-Kingsville. Major Advisor: S.D. Nelson.
- Master of Science Thesis: Catherine R. Simpson. Aug. 2005. Volatilization Loss of Vapam and K-pam in Different Soil Types and Varying Organic Matter Levels. Texas A&M University-Kingsville. Major Advisor: S.D. Nelson.
|
Progress 10/01/03 to 09/30/04
Outputs
Few studies have focused on comparing the field off-gassing potential of MITC when metam sodium is applied by direct soil injection, sprinkler application, and drip fumigation. These field studies were aimed at improving the understanding of soil MITC doses and its off-gassing rates relative to biological performance. The general objective of these field trials was to acquire data on air quality, soil characteristics, meteorological conditions, and crop production in States currently using soil fumigation practices, like CA and FL. Data for this research involved two field sites in CA (fall 2002 and spring 2003) and one field site in FL (spring 2003). In addition, laboratory trials in TX were performed to simulate MITC volatilization from the soil profile using 60-cm steel columns. These lab tests evaluated the influences that varying water application rates have on MITC retention in the soil-air phase. Lastly, actual field data will be used in conjunction with the
EPA dispersion model ISCST3 to model the off-field exposure of potential MITC release in the atmosphere. Modeling work is being performed by meteorologists located in Alexandria, Virginia. Field data on MITC soil-air and atmospheric release has been collected from several field studies performed in September 2002 at Bakersfield, CA, March 2003 at Citra, FL, and February 2004 at Salinas, CA. Studies in California covered off-gassing emissions from a loamy-sand soil under metam sodium application via sprinkler overhead application vs. drip fumigation. Florida studies involved MITC emission monitoring and vegetable crop production evaluations after metam sodium application via direct soil injection vs. drip fumigation in a fine sandy soil. Laboratory studies with metam sodium were done at Texas A&M University-Kingsville, TX to simulate soil off-gassing when water is used as a potential soil seal to prevent and/or minimize MITC release into the atmosphere. This work was performed by a
Masters graduate student, Mr. Jerry Stratmann, who graduated in May 2004 with a Thesis on this work.
Impacts
The potential benefit of this work will help determine the likelihood ofwhether drip fumigation with metam-sodium is a safe and reliable soil fumigant alternative to replace methyl bromide. Results from the soil column studies was presented at the November 2004 annual ASA-CSSA-SSSA meetings held in Seattle, WA for presentation to other professional scientists involved in similar work. Presentation of final research findings to growers is planned through local grower field days, extension activities, and publications after all crop growth data is collected, analyzed, and modeling work is completed. Findings from these studies will aid the USDA CSREES Methyl Bromide Transitions Program by its contributing to better and safer application methodologies for metam sodium as a replacement for methyl bromide. This work will assist growers and researchers in the potential transition from conventional soil injection of metam sodium to drip fumigant application methods. This
would provide growers with the necessary information on the chemical dispersion within the bed, off-gassing potential, and an accurate pest control reliability assessment of metam-sodium when applied by various methods. The overall aim of this work is to provide evidence to support safer and more environmentally conscience soil fumigant application methods.
Publications
- A peer-reviewed manuscript was accepted for publication in the 2004 issue of Subtropical Plant Science, Journal of the Rio Grande Valley Horticultural Society. S.D. Nelson, D.W. Dickson, H.A. Ajwa, and D.A. Sullivan. 2004. Efficacy of metam sodium under drip and surface spray application in Florida tomato production. Subtropical Plant Science. Vol. 56: (In Press).
- Thesis was published. May 2004. J.E. Stratmann. The Development of Metam Sodium Application Methods for Minimizing Volatilization. Master of Science Thesis. Texas A&M University-Kingsville.
- Abstract published in 2004: S.D. Nelson, J.E. Stratmann, and H.A. Ajwa, , and T. Trout. Minimizing soil fumigant off gassing by using a soil surface water seal. Annual ASA-CSSA-SSSA meetings. Seattle, WA. Oct. 31-Nov. 4, 2004.
|
Progress 09/01/02 to 08/31/03
Outputs
Specific Aims: Few studies have focused on comparing the field off-gassing potential of MITC when metam sodium is applied by direct soil injection, sprinkler application, and drip fumigation. These field studies are aimed at improving the understanding of soil MITC doses and its off-gassing rates relative to biological performance. The general objective of field trials is to acquire data on efficacy, air quality, soil characteristics, meteorological conditions, and crop production in States currently using soil fumigation practices, like CA and FL. Data for this research involves two field sites in CA during the fall 2002 and spring 2004, and one field site in spring 2003 at FL. In addition, laboratory trials in TX are being performed to simulate MITC volatilization from the soil profile using 60 cm steel columns. These lab tests evaluate the influences varying water application rates have on MITC retention in the soil-air phase. Lastly, actual field data will be used
in conjunction with the EPA dispersion model ISCST3 to model the off-field exposure of potential MITC release in the atmosphere. Modeling work is being performed by meteorologists located in Alexandria, Virginia. Results and Benefits: Field data on MITC soil-air and atmospheric release has been collected from one study in late September 2002 at Bakersfield, CA, and another field study in early March 2003 at Citra, FL. Studies in California covered off-gassing emissions from a loamy-sand soil under metam sodium application via sprinkler overhead application vs. drip fumigation. Florida studies involved MITC emission monitoring and vegetable crop production evaluations after metam sodium application via direct soil injection vs. drip fumigation in a fine sandy soil. Laboratory studies with metam sodium are being done at Texas A&M University-Kingsville, TX to simulate soil off-gassing potential when water is used as a potential soil seal to prevent and/or minimize MITC release into the
atmosphere. This work is being performed by a Masters graduate student, Mr. Jerry Stratmann. Plans for the Coming Year: Laboratory studies using soil columns will continue to evaluate different amounts of water and soil temperature conditions effects on MITC volatilization. Field work in California will be done in the spring of 2004 to evaluate MITC release during cooler season temperatures. Two fields were located for this experiment. The tentative date for starting land preparation is January 15, 2004. Modeling work of field off-gassing data will begin and its analysis will be compared against generated EPA program models. Publications are to be expected after the completion of all projects and in print the latter part of 2004 to early 2005. It is of utmost importance to get this data out considering the short time table left on finding reliable alternatives to methyl bromide.
Impacts
The potential benefit of this work is to determine the likelihood of drip fumigation with metam-sodium as a safe and reliable soil fumigant alternative to replace methyl bromide. Results from the soil column studies will be presented at the November 2003 annual ASA-CSSA-SSSA meetings to be held in Denver, CO for presentation to professional scientists involved in similar work. Additional preliminary field trial results will be presented at the annual 2003 Methyl Bromide Alternative Outreach meetings to be held in October at San Diego, CA. Presentation of final research findings to growers is planned through local grower field days, extension activities, and publications after all crop growth data is collected, analyzed, and modeling work is completed. Findings from these studies will aid the USDA CSREES Methyl Bromide Transitions Program by its contributing to better and safer application methodologies for metam sodium as a replace for methyl bromide. This work will
assist growers and researchers in the potential transition from conventional soil injection of metam sodium to drip fumigant application methods. This in turn would provide growers will the necessary information on the chemical dispersion within the bed, off-gassing potential, and the pest control reliability of metam-sodium when applied by various methods. The overall aim of this work is to provide evidence to support safer and more environmentally conscience soil fumigant application methods.
Publications
- Publications: No publications have yet been produced. Abstracts on data collected and analyzed to date are being processed for presentation at Methyl Bromide Alternative Outreach conference to be held in San Diego, CA and abstracts will be in print by Nov. 2003.
- Project Co-PIs and Collaborators: Dr. Husein A. Ajwa, U.C. Davis c/o USDA-ARS, Salinas, CA; Dr. Don W. Dickson, Univ. of Florida, Gainesville, FL; and Mr. David A. Sullivan and Mark T. Holdsworth, Sullivan Environmental Consulting, Inc., Alexandria, VA; and Mr. Jerry Stratmann, M.S. graduate student, TAMUK, Kingsville, TX, (projected graduation date May 2004).
|
|