Progress 03/01/10 to 02/28/15

Outputs
Target Audience:Organic Producers and professionals working in organic agriculturewere main target. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Project wasused to train 5graduate students and 1 postdoc. Total of 5 graduate students resulted from this project, including: 2 PhD thesis [Santiago Ulloa (defended in 2012), Chris Bruening (to defend in 2016)] and 3 MS thesis [(Chris Bruening (2011) and Brian Neilson (2012), Strahinja Stepanovic (2013)]. How have the results been disseminated to communities of interest?It was done via: Field days, Field Demonstration, Manual for Flame Weeding, Articles in various journals and magazines and 19 research publications. We shared information on dose response curves for propane for several major weed species with organic producers (via extension meetings) and research communities (via 5 conferences). We also wrote a manual for flame weeding, which became a "Bible for flame weeding". I was invited to talk about flame weeding at 12 organic group meetings in Midwest (Nebraska, Illinois, Iowa, Michigan, Wisconsin, Colorado, and South Dakota), with total attendance of almost 4000 organic growers. Based on the conversations, many organic growers expressed appreciation for our work, and many said that this information will save them 80-200 dollars per acre on weed control. Our flame weeding machines were also demonstrated at 12 field days in Nebraska, Illinois, Iowa, Michigan, Wisconsin, Colorado, and South Dakota) Every year (from 2008-2015, during month of August) we have conducted a full day Workshop on Flame Weeding at NEREC-HAL, with yearly attendance of about 50 producers (total of over 400 producers) from: Nebraska, Wisconsin, Iowa, Minnesota, South Dakota, Colorado, New York, California, Florida, Mississippi, Ohio, Michigan, and Virginia. What do you plan to do during the next reporting period to accomplish the goals?This is Final report, thus there is no next reporting period.

Impacts
What was accomplished under these goals? Objective 1: To develop response curves for propane [based on flame intensity (BTU units) or usage rate (gall/acre)] needed for safe and economical weed control. Output for objective 1: We have developed dose response curves for propane needed for safe and economical control of several major weed species and published 5 manuscripts from this objective reported in 2011. One PhD student (Ulloa) graduated. Experiment 1: Growth stage influenced differential response of foxtail and pigweed species to broadcast flaming: In general, foxtail species were more tolerant than pigweed species. For example, about 85 and 86 kg/ha were the calculated doses needed for 90% dry matter reduction in five-leaf green foxtail and four-leaf yellow foxtail compared with significantly lower doses of 68 and 46 kg/ha of propane for five-leaf redroot pigweed and common waterhemp, respectively. However, none of the doses we tested could provide 90% dry matter reduction in foxtail species at flowering stage. It is important to note that foxtail species started regrowing 2 to 3 wk after flaming. Experiment 2: Weed control & crop tolerance to propane flaming as influenced by the time of day: All plant species were more susceptible to flaming during the afternoon when they had lower leaf RWC at 8 HAS; however, the response of these plants did not differ with the plants flamed at 12 HAS. Green foxtail flamed at 87 kg ha_1 at 0, 8 and 12 HAS had injury of 62, 76 and 82%, respectively. The same response was observed in velvetleaf which had 80% injury when flamed with 87 kg ha_1 at 0 HAS and 93% injury when flamed at 12 HAS with the same propane dose at 7 DAT. Similar trends occurred for maize and soybean. Objective 2: To evaluate crop yields and yield components as influenced by various levels of crop injury caused by broadcast flaming in three agronomic crops (field corn, soybean, and sorghum). Output for objective 2: We have evaluated crop yields and yield components as influenced by various levels of crop injury caused by broadcast flaming in several agronomic crops (field corn, popcorn, sweetcorn, soybean, and sorghum), and published 10 manuscripts from this objective. Experiment 1: Popcorn (Zea mays L. var. everta) yield and yield components as influenced by the timing of broadcast flaming: Popcorn response to flaming was influenced by the crop growth stage and propane dose. Based on various parameters evaluated, popcorn flamed at the 5-leaf showed the highest tolerance while the 2-leaf was the most susceptible stage. The maximum yield reductions were 45%, 9% and 16% for the 2-leaf, 5-leaf and 7-leaf stages, respectively. In addition, propane doses that resulted in a 5% yield loss were 23 kg ha_1 for the 2-leaf and 7-leaf and 30 kg ha_1 for the 5-leaf stage. Experiment 2: Growth stage impacts tolerance of winter wheat (Triticum aestivum L.) to broadcast flaming: In general, wheat at 3 T was the most tolerant and at BS was the most susceptible stage to broadcast flaming. Flaming negatively affected all yield components of wheat. Reduction of grain yield increased with increase in propane dose at each growth stage. The maximum yield losses of about 21%, 32%, 63% and 74% were obtained with the highest propane dose of 87 kg ha_1 applied at 3 T, SE, 4L and BS growth stages, respectively. Due to unacceptable yield loss, the use of broadcast flaming in winter wheat at the tested growth stages is not recommended. Experiment 3: Timing of broadcast Flaming influenced yield and yield components in sweet maize (Zea mays L. var. rugosa): Based on most parameters tested, V7 was the most tolerant while V2 was the least tolerant stage for broadcast flaming. The maximum yield reductions with the highest propane dose of 85 kg ha−1 were 22%, 12% and 6% for V2, V5 and V7 stages, respectively. Furthermore, a 5% yield reduction was evident with 23, 25 and 36 kg ha−1 of propane for V2, V5 and V7 growth stages, respectively, suggesting that plants flamed at V7 stage can tolerate higher dose of propane for the same yield reduction compared to the other growth stages. We believe that flaming has a potential to be used effectively in organic sweet maize production if properly used. Objective 3: To test flaming as a tool for weed control versus mechanical weed control and their overall impact on soil erosion Output for Objective 3: We have compared flaming as a tool for weed control in corn versus mechanical cultivation and their overall impact on soil erosion: (1) Flaming provided better weed control than cultivation regardless of timings of treatment application. (2) Early season flame weeding provided better weed control compared to late season flaming. For example, weed control ratings ranged from 45 to 75% in the early flaming plots compared to 35 to 60% in the late flaming. (3) Cultivation provided only 30% weed control at 14 days after treatment (DAT), regardless of timings, whereas as high as 75% and 60% were observed for early and late timings of flaming, respectively. Objective 4: To evaluate newly designed torches with flaming hoods and incorporate them into a four-row unit cropping system for two agronomic crops (field corn and soybean) Output for Objective 4: We evaluated newly designed torches with flaming hoods and incorporate them into a 4-row unit for use in two agronomic crops (field corn and soybean). Results: Torches and hoods performed well, thus a 4-row flame weeding machine was created and tested at the field level. This flame weeding machine was demonstrated at various Field Days from 2009-2011, which generated interest from Organic Producers and resulted in further adoption of this methodology among producers. For example, over a 3-year period, about 46 flame weeding machines were built based on our design across Nebraska, Iowa, Wisconsin and Minnesota. This resulted in converting weed control methods from inter-row cultivation and hand-weeding (as primary weed control method) to flaming at over 5000 acres. One producer from Nebraska communicated to us that using our flame weeding recipes saved him over $60,000/year on the cost of manual labor for weed control. (eg. flame weeding costs $10-15/acre compared to $150-300/acre for hand-weeding). Objective 5: To evaluate an integrated approach for weed control based on mechanical cultivation and flaming in corn and soybean. Output for objective 5: We finished the last year of studies of an integrated approach for weed control based on mechanical cultivation and flaming in corn and soybean. Results from soybean study: The combination of mechanical cultivation and banded flaming applied twice (at VC and V4-V5) was the best treatment resulting in 80-82% weed control and 6-9% crop injury at 28 DAT and 3.41-3.67 t ha−1 yield. Cultivation conducted twice provided only 19% weed control at 28 DATand 1.75 t ha−1 yield. Soybean plants recovered well after all flaming treatments, with the exception of broadcast flaming conducted twice (28% crop injury at 28 DAT). Combining flaming with cultivation has a potential to effectively control weeds in organic soybean production across a range of FRs. ?Results from corn study: Overall, maize showed good tolerance to all flaming treatments averaging only 5.1% and 3.6% crop injury at 28 days after treatment in no-manure and manure plots, respectively. The best weed control was achieved with banded flaming followed by aggressive cultivation, providing over 90% weed control and yields of 7.8 t ha21, and flame-cultivation conducted twice as a single operation, giving 88% weed control and yields of 7.5 t ha21, conducted twice at the V3 and V6 growth stages. Broadcast flaming conducted twice provided 70% weed control and yielded 6.0 t ha21. These results suggest that flaming and cultivation applied separately or combined in a single operation, as a single trip across the field, have a potential to be used for weed control in organic maize production systems.

Publications

• Type: Journal Articles Status: Published Year Published: 2014 Citation: 1. Knezevic and Ulloa. 2007. Flaming: New potential tool for weed control in organically grown agronomic crops. Journal of Agricultural Sciences.52, 2:95-104 2. Heverton T.Z., S. Ulloa, A.Datta and S. Knezevic. 2008. Corn (Zea mays) and soybean (Glycine max) tolerance to broadcast flaming. RURAL. Vol 3, Issue 1, Article. http://digitalcommons.unl.edu/rurals/vol3/iss1/1. 3. Domingues A., S.Ulloa, Datta and Knezevic. 2008. Weed control with broadcast flaming. RURAL. Volume 3, Issue 1, article 2. 4. Knezevic, S. C.M. da Costa, S.M. Ulloa and A. Datta 2009. Response of corn (Zea mays L.) types to Broadcast flaming. The 8th EWRS workshop on Physical and Cultural Weed control. Pages 92-98, Zaragoza, Spain, 9-11 March 2009. 5. Knezevic, S., S.M. Ulloa and A. Datta 2009. Growth stage impacts tolerance to broadcast flaming in agronomic crops. The 8th EWRS workshop on Physical and Cultural Weed control. Pages 86-91, Zaragoza, Spain, 9-11 March 2009. 6. Knezevic, S., S.M. Ulloa and A. Datta 2009. Tolerance of selected weed species to broadcast flaming at different growth stages. The 8th EWRS workshop on Physical and Cultural Weed control. Pages 98-103, Zaragoza, Spain, 9-11 March 2009. 7. Knezevic, S. J.F. Neto, S.M. Ulloa and A. Datta 2009. Winter wheat (Triticum aestivum L.) tolerance to broadcast flaming. The 8th EWRS workshop on Physical and Cultural Weed control. Pages 104-109, Zaragoza, Spain, 9-11 March 2009. 8. Ulloa, S. M., Datta, A., Bruening, C., Neilson, B., Miller, J., Gogos, G., Knezevic, S. Z. (2011). Maize response to broadcast flaming at different growth stages: Effects on growth, yield and yield components. European Journal of Agronomy. 32:10-19 9. Ulloa, S. M., Datta, A., Knezevic, S. Z. (2011). Growth stage influenced sorghum response to broadcast flaming: Effects on yield and its components. Agronomy Journal 103: 7-12. 10. Ulloa, S. M., Datta, A., Cavalieri, S. D., Lesnik, M., Knezevic, S. Z. (2010). Popcorn (Zea mays L. var. everta) yield and yield components as influenced by the timing of broadcast flaming. Crop Protection 29: 1496-1501. 11. Ulloa, S. M., Datta, A., Malidza, G., Leskovsek, R., Knezevic, S. Z. (2010). Yield and yieldcomponents of soybean [Glycine max (L.) Merr.] are influenced by the timing of broadcast flaming. Field Crops Research 119:348-354. 12. Ulloa, S. M., Datta, A., Knezevic, S. Z. (2010). Tolerance of selected weed species to broadcast flaming at different growth stages. Crop Protection 29:1381-1388.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: 13. Ulloa, S. M., Datta, A., Knezevic, S. Z. (2010). Growth stage impacts tolerance of winter wheat (Triticum aestivum L.) to broadcast flaming. Crop Protection doi 10.1016/j.cropro.2010.04.009. 14. Ulloa, S. M., Datta, A., Knezevic, S. Z. (2010). Growth stage influenced differential response of foxtail and pigweed species to broadcast flaming. Weed Technology 24:319-325. 15. Ulloa, S. M., Datta, A., Malidza, G., Leskovsek, R., Knezevic, S. Z. (2010). Timing of broadcast Flaming influenced yield and yield components in sweet maize (Zea mays L. var. rugosa). Field Crops Research 118: 282-288. 16. Ulloa, S. M., Datta, A., Bruening, C., Neilson, B., Miller, J., Gogos, G., Knezevic, S. Z. (2011) .Weed control & crop tolerance to propane flaming as influenced by the time of day. Crop Protection 31:1-7. 17. Datta, A., & Knezevic, S. Z. (2013). Flaming as an Alternative Weed Control Method for Conventional and Organic Agronomic Crop Production Systems: A Review. In D. L. Sparks (Ed.), Advances in Agronomy (pp. 399-428). Elsevier Inc. 18. Knezevic S., Stepanovic. S, Datta A, Nedeljkovic D and Tursun N. 2013. Soybean yield and yield components as influenced by the single and repeated flaming. Crop Protection 50:1-5. 19. Knezevic S., Stepanovic S, and Datta A. 2014. Growth Stage Affects Response of Selected Weed Species to Flaming Propane. Weed Technology, 28(1):233-242

Progress 10/01/13 to 09/30/14

Outputs
Target Audience: Organic producers Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Flame Weeding Workshop, a full day program with lectures and demonstration of flame weeding equipment How have the results been disseminated to communities of interest? Yes, via workshops and field tours What do you plan to do during the next reporting period to accomplish the goals? Need to submit final report as this project is completed

Impacts
What was accomplished under these goals? Introduction: Weeds are major problem in both conventional and organic farming throughout the world. In order to reduce yield loss, weeds must be controlled. However, ground and surface water contamination and pesticide residues in food have sparked public awareness of and restrictions on herbicide use (Mojzis and Rifai 1995). For these reasons, many weed scientists are considering alternative and integrated weed management practices to reduce herbicide inputs and impacts (Rifai et al. 2000). Some called alternative control methods as "many little hammers", in the tool box of weed control (Liebman and Gallandt 1997). One of the little hammers can be the use of propane flaming for weed control. Some suggested an increasing interest in thermal methods of weed control, as they leave no residual effects on soil, water and food quality (Ascard 1998). The use of propane for flame weeding could be one of the alternative control methods for weed control, not only organic but also in non-organic cropping systems. During the flaming process, the heat from the flame is transferred to the plant tissues (Lague et al. 2000) and results in the coagulation of cell proteins if the temperature reaches above 50 °C (Parish 1990). Furthermore, exposing plant tissue to a temperature of about 100 °C for a split second (eg. 0.1 second) can result in cell membrane rupture (Pelletier et al. 1995; Morelle 1993), resulting in loss of water and plant death (Rifai et al. 1996). Plants may survive flaming, either by avoidance or by heat tolerance. The extent to which heat from the flames penetrates plants depends on the flaming technique and leaf surface moisture (Lien et al. 1967; Vester 1988; Parish 1990). Flame weeding is less costly than hand-weeding (Ascard 1990; Nemming 1994) and can be used when the soil is too moist for mechanical weeding. Flaming can also provide added benefits, such as insect and/or disease control (Lague et al. 1997). Therefore, it is suggested for these 5years (2010-2014) to study the various issues related to the use of flaming as a tool for weed control in organic cropping systems. If promising, the results of this 5-year work can be further studied for use in conventional crops, even compared with various herbicide treatments. Specific objectives: The specific five objectives of my program for this five year period (2010-2014) will provide a frame work for using flaming as a weed control, and they include: To develop response curves for propane [based on flame intensity (BTU units) or usage rate (gall/acre)] needed for safe and economical weed control. Basic economics of an effective propane does will be also evaluated. To evaluate crop yields and yield components as influenced by various levels of crop injury caused by broadcast flaming in three agronomic crops (field corn, soybean, and sorghum). To test flaming as a tool for weed control versus mechanical weed control and their overall impact on soil erosion. To evaluate newly designed torches with flaming hoods and incorporate them into a four-row unit cropping system for two agronomic crops (field corn and soybean). To evaluate an integrated approach for weed control based on mechanical cultivation and flaming in corn and sunflower. Outputs by objective: Objective 1 is completed. We have developed dose response curves for propane needed for safe and economical control of several major weed species and published 2 manuscripts from this objective reported in 2011. One PhD student (Ulloa) graduated. Objective 2 is completed. We have evaluated crop yields and yield components as influenced by various levels of crop injury caused by broadcast flaming in several agronomic crops (field corn, popcorn, sweetcorn, soybean, and sorghum), and published 5 manuscripts from this objective reported in 2011. One MS Student (Bruening) graduated Objective 3 is completed. We have compared flaming as a tool for weed control in corn versus mechanical cultivation and their overall impact on soil erosion. There is no publication from this objective. Objective 4 is completed. We evaluated newly designed torches with flaming hoods and incorporate them into a 4-row unit for use in two agronomic crops (field corn and soybean). In 2013 we also tested a 8-row flame weeding unit. Data is being analyzed as part of PhD thesis (Bruening), who plans to graduate in May of 2015. Objective 5 is completed. We finished the last year of studies of an integrated approach for weed control based on mechanical cultivation and flaming in corn and soybeans. MS student (Strahinja Stepanoci) who graduated in January 2014. Outcomes/Impacts: We shared information on dose response curves for propane for several major weed species with organic producers (via extension meetings) and research communities (via 5 conferences). We also wrote a manual for flame weeding, which became a bible for weed control I was invited (during last 12 months) to talk about flame weeding at four organic group meetings in Midwest (Nebraska, Illinois, Iowa, and South Dakota), with total attendance of almost 3000 organic growers. Based on the conversations, many organic growers expressed appreciation for our work, and many said that this information will save them 80-200 dollars per acre on weed control. Our flame weeding machines were also demonstrated at two field days in Iowa (Jefferson and Stanton) and South Dakota (Beresford). On August 14 of 2014 we have conducted a full day Workshop on Flame Weeding at NEREC-HAL, with attendance of 52 producers from Nebraska, Wisconsin, Iowa, Minnesota, South Dakota, and Colorado. Our research sites were also usedfor a total of 5 extension activities and field tours to teachorganic producers about the use of flame weeding. About 200 organic producers came to the field Tours and Demonstrations. Many of them asked for drawings and designs for building flame weeding machines to control weeds in their operations. Based on our communications with producers we believe that 63 flame weeding machines were built using our designs. Total of 5 graduate students resulted from this project, including: 2 PhD thesis [Santiago Ulloa (defended in 2012), Chris Bruening (to defend in 2014)] and 3 MS thesis [(Chris Bruening (2011) and Brian Neilson (2012), Strahinja Stepanovic (2013)].

Publications

Progress 10/01/12 to 09/30/13

Outputs
Target Audience: Organic producers in NE and neighboring states Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? MS student (Strahinja Stepanoci PhD thesis (Chris Bruening) How have the results been disseminated to communities of interest? We shared information on dose response curves for propane for several major weed species with organic producers (via extension meetings) and research communities (via 3 conferences). I was invited to talk about flame weeding at five organic group meetings in Midwest (Nebraska, Illinois, Iowa, Wisconsin and South Dakota), with total attendance of almost organic growers). Based on the conversations, most growers expressed appreciation for our work, and many said that this information will save them 50-150 dollars per acre on weed control. Our flame weeding machines were also demonstrated at two field days in Iowa (Jefferson and Stanton) and South Dakota (Beresford). On August 21 of 2013 we have conducted a full day Workshop on Flame Weeding at NEREC-HAL, with attendance of 48 producers from Nebraska, Iowa, California Minnesota, South Dakota, and Colorado. Our research sites were also usedfor various extension activities and field tours to teachorganic producers about the use of flame weeding. About 200 organic producers came to the field Tours and Demonstrations. Many of them asked for drawings and designs for building flame weeding machines to control weeds in their operations. Based on our communications with producers we believe that 36 flame weeding machines were built using our designs. What do you plan to do during the next reporting period to accomplish the goals? Graduate 2 students (Chris bruneing and Strahinja Stepanovic). Also publish several manuscripts from grad student thesis

Impacts
What was accomplished under these goals? Objective 4 is completed. We evaluated newly designed torches with flaming hoods and incorporate them into a 4-row unit for use in two agronomic crops (field corn and soybean). In 2013 we also tested a 8-row flame weeding unit. Data is being analyzed as part of PhD thesis (Bruening), who plans to graduate in May of 2014. Objective 5 is completed. We finished the last year of studies of an integrated approach for weed control based on mechanical cultivation and flaming in corn and soybeans.

Publications

Progress 10/01/11 to 09/30/12

Outputs
OUTPUTS: Objective 1 is completed. We have developed dose response curves for propane needed for safe and economical control of several major weed species and published 2 manuscripts from this objective reported in 2011. One PhD student (Ulloa) graduated. Objective 2 is completed. We have evaluated crop yields and yield components as influenced by various levels of crop injury caused by broadcast flaming in several agronomic crops (field corn, popcorn, sweetcorn, soybean, and sorghum), and published 5 manuscripts from this objective reported in 2011. One MS Student (Bruening) graduated Objective 3 is completed. We have compared flaming as a tool for weed control in corn versus mechanical cultivation and their overall impact on soil erosion. There is no publication from this objective. Objective 4: It is still underway. We evaluated newly designed torches with flaming hoods and incorporate them into a 4-row unit for use in two agronomic crops (field corn and soybean). In 2013 we plan on testing a 8-row flame weeding unit. Data is being analyzed as part of PhD thesis (Bruening). Objective 5: We are still evaluating an integrated approach for weed control based on mechanical cultivation and flaming in corn and soybeans, this work will be repeated in 2013. PARTICIPANTS: Dr. Stevan Knezevic, Dr. George Gogos (Collaborator), Dr. Avishek Datta (post-doc), Santiago Ulloa (PhD student), Chris Bruening (PhD student), Brian Neilson(Ms Student), Strahinja Stepanovic (MS student) TARGET AUDIENCES: Organic producers in NE and neighboring states PROJECT MODIFICATIONS: no changes were made

Impacts
We shared information on dose response curves for propane for several major weed species with organic producers (via extension meetings) and research communities (via 3 conferences). I was invited to talk about flame weeding at five organic group meetings in Midwest (Nebraska, Iowa, Wisconsin and South Dakota), with total attendance of over 1000 organic growers). Based on the conversations, most growers expressed appreciation for our work, and many said that this information will save them 50-150 dollars per acre on weed control. Our flame weeding machines were also demonstrated at two field days in Iowa (Jefferson and Stanton) and South Dakota (Beresford). On August 15 of 2012 we have conducted a full day Workshop on Flame Weeding at NEREC-HAL, with attendance of 28 producers from Nebraska, Iowa, Minnesota, South Dakota, Colorado and Florida. Our research sites were also used for various extension activities and field tours to teach organic producers about the use of flame weeding. Over 250 organic producers came to the field Tours and Demonstrations. Many of them asked for drawings and designs for building flame weeding machines to control weeds in their operations. Based on our communications with producers we believe that 36 flame weeding machines were built using our designs. A PhD thesis (Santiago Ulloa) and 2 MS thesis (Chris Bruening and Brian Neilson) were resulting from this project. Current Students on this project are: Chris Bruening (continue working with us for his PhD) and Strahinja Stepanovic (MS)

Publications

• Ulloa, S. M., Datta, A., Bruening, C., Neilson, B., Miller, J., Gogos, G., Knezevic, S. Z. (2011) .Weed control & crop tolerance to propane flaming as influenced by the time of day. Crop Protection 31:1-7.
• Knezevic, Datta, Bruening and Gogos, 2012. Propane Fueled Flame Weeding in corn, soybean and sunflower. http://www.agpropane.com/ContentPageWithLeftNav.aspxid=1916

Progress 10/01/10 to 09/30/11

Outputs
OUTPUTS: As part of objective 1, we have developed dose response curves for propane needed for safe and economical control of several major weed species. As part of objective 2, we evaluated crop yields and yield components as influenced by various levels of crop injury caused by broadcast flaming in several agronomic crops (field corn, popcorn, sweetcorn and soybean, and sorghum). As part of objective 3, we tested flaming as a tool for weed control in corn versus mechanical cultivation and their overall impact on soil erosion. Data is being analyzed. As part of objective 4, we evaluated newly designed torches with flaming hoods and incorporate them into a four-row unit cropping system for two agronomic crops (field corn and soybean). Data is being analyzed As part of objective 5, we are still evaluating an integrated approach for weed control based on mechanical cultivation and flaming in corn and sunflower. PARTICIPANTS: Dr. Stevan Knezevic, Dr. George Gogos (Collaborator), Dr. Avishek Datta (post-doc), Santiago Ulloa (PhD student), Chris Bruening (PhD student), Brian Neilson(Ms Student) TARGET AUDIENCES: Target audience: Organic producers in NE and neighboring states PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
1. I was invited to talk about flame weeding at seven organic group meetings in Midwest (Nebraska, Iowa, Missouri, Minnesota, Wisconsin and South Dakota), with total attendance of over 2000 organic growers). Based on the conversations, most growers expressed appreciation for our work, and many said that this information will save them 50-150 dollars per acre on weed control. 2. In August of 2001 we conducted a full day workshop on flame weeding at NEREC-HAL, with attendance of 30 people from academia and state/federal agencies. This workshop was not open to general public as the objective was to educate other educators about the potential use of weed flaming 3. Research sites were used as part of various extension activities and field tours to teach organic producers about the use of flaming for weed control. Over 50 organic producers came to the field Tours, and several of them showed asked for drawings and designs for building flamers to control weeds in their operations. 4. A PhD thesis for Santiago Ulloa was conducted as part of the project.

Publications

• Ulloa, S. M., Datta, A., Knezevic, S. Z. (2010). Growth stage influenced differential response of foxtail and pigweed species to broadcast flaming. Weed Technology 24:319-325.
• Ulloa, S. M., Datta, A., Cavalieri, S. D., Lesnik, M., Knezevic, S. Z. (2010). Popcorn (Zea mays L. var. everta) yield and yield components as influenced by the timing of broadcast flaming. Crop Protection 29: 1496-1501.
• Ulloa, S. M., Datta, A., Malidza, G., Leskovsek, R., Knezevic, S. Z. (2010). Yield and yield components of soybean (Glycine max (L.) Merr.) are influenced by the timing of broadcast flaming. Field Crops Research 119:348-354.
• Ulloa, S. M., Datta, A., Knezevic, S. Z. (2010). Tolerance of selected weed species to broadcast flaming at different growth stages. Crop Protection 29:1381-1388.
• Ulloa, S. M., Datta, A., Bruening, C., Neilson, B., Miller, J., Gogos, G., Knezevic, S. Z. (2011). Maize response to broadcast flaming at different growth stages: Effects on growth, yield and yield components. European Journal of Agronomy, 32:10-19. Ulloa, S. M., Datta, A., Knezevic, S. Z. (2011). Growth stage influenced sorghum response to broadcast flaming: Effects on yield and its components. Agronomy Journal 103: 7-12.

Progress 10/01/09 to 09/30/10

Outputs
OUTPUTS: Objective 1: To develop dose response curves for propane needed for safe and economical weed control. Material and methods (brief): Following weed species were planted and tested for tolerance to flaming: wild buckwheat, field bindweed, redroot pigweed, common waterhemp, lambs quarter, velvetleaf, Venice mallow, tall waterhemp, yellow sweet clover, yellow foxtail, green foxtail, and barnyardgrass. The experiment was established at Haskell Ag Lab as a randomized complete block design with 21 treatments and 4 replications. Treatments were in a factorial arrangement of 7 propane doses and 3 application times. Flaming was based on the plant leaf stage: (1) at the 2nd -3rd leaf stage (early POST), (2) at the 6 - 7th leaf stage (mid POST) and (3) at the 10 - 12th leaf stage (late POST). Visual ratings of percent weed control was conducted at approximately 3, 7 and 14 days after flaming operation and it was based on a scale from 0 to 100 (where 0 = no injury and 100 = plant death). Data is being analyzed. Objective 2: To evaluate crop yields and yield components as influenced by various levels of crop injury caused by broadcast flaming in five agronomic crops (field corn, popcorn, sweetcorn and soybean, and sorghum). Material and methods: There were 3 experiments with 3 corn types (field corn, sweet corn and popcorn. Each experiment was a randomized complete block design with 12 treatments and 4 replications for each crop. Treatments had a factorial arrangement of 4 crop injury levels and 3 growth stages of the crop. Targeted injury levels included: 0, 10%, 30%, and 50% in each crop. The 3 growth stages were based on the plant leaf stage: (1) V2-V3 leaf stage (early POST), (2) V5-V7 stage (mid POST) and (3) V7-10 leaf stage. Visual ratings of percent crop injury was conducted at approximately 1 day after the flaming treatment (DAT), 3, 7, 14, 21, 28, and 56 DAT, and it was based on a scale from 0 to 100 (where 0 = no injury and 100 = plant death). Yield and yield components were determined as part of the final yield data. Data is being analyzed. PARTICIPANTS: Dr. Stevan Knezevic, Dr. George Gogos (Collaborator), Dr. Avishek Datta (post-doc), Santiago Ulloa (PhD student), Chris Bruening (PhD student), Brian Neilson(Ms Student) TARGET AUDIENCES: Organic producers in NE and neighboring states PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Data is being analyzed and prepared for posters and presentation at the NCWSS in December of 2010. Research sites were used as part of various extension activities and field tours to teach organic producers about the use of flaming for weed control. Over 50 organic producers came to the field Tours, and several of them showed asked for drawings and designs for building flamers to control weeds in their operations.

Publications

• No publications reported this period