Progress 07/15/06 to 07/14/09
Outputs
OUTPUTS: Activities: Studies with blueberries in high tunnels were conducted in Georgia, while studies on high tunnel production of raspberries and blackberries were conducted in Arkansas. All data collected from the blueberry trials have been analyzed, while the final data on blackberries are still being collected at this time. Information from these studies was used to develop interactive production budgets for organic high tunnel blackberry and raspberry production. Teaching activities that were part of the project includes mentoring of two MS students, and the involvement of undergraduate students in this research. The high tunnels at the University of Georgia were also used as part of the new organic agriculture teaching program. These high tunnels have become an integral part of this teaching program. Four graduate students in horticulture and plant biology used the blueberry planting as part of a class research project. The aim was to quantify the effect of high tunnels on diurnal changes in soil, air, leaf, and flower bud temperatures. Events: An open house, focusing on organic production in high tunnels was held at the University of Georgia's horticulture farm with approximately 60 growers attending. Presentations about this research were given at grower and scientific meetings. Products resulting from this research include two students who received their MS degrees while working on this project (B. Haywood at the University of Arkansas worked on production budgets for blackberries and raspberries in high tunnels, while A. Ogden at the University of Georgia studies blueberry production in nigh tunnels. A website with information regarding high tunnels and organic production was developed as part of the open house in Georgia (http://www.hortphys.uga.edu/hightunnel.html). The website contains all presentation from the open house, which can be downloaded in PDF format. The project goals and opportunities for high tunnel alternate season production of blackberries were presented at talks at the Arkansas-Oklahoma Horticulture Industries Meeting and Trade Show (January, 2007), and at a blackberry production workshop (June, 2007). Two Excel spreadsheets were developed to allow growers to do an economic analysis of the organic production of blackberries and raspberries in high tunnels. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: The target audience for this project consisted of organic growers in the Southeast, and specifically owners of small farms who would benfit from an extended harvest season to spread out cash flow over a longer period. These growers were actively engaged through open houses or workshops in Arkansas and Georgia. PROJECT MODIFICATIONS: Project modifications were minimal. Collaboration with students in an ecophysiology class at the University of Georgia allowed for more extensive measurements of plant, air, and soil temperatures than initially planned. An economic analysis of blueberry production in high tunnels was not possible, because field-grown plants never yielded. The cultivars used in this study flowered early, exposing the field-grown flowers and young fruits to freezes. Therefore economic comparisons between high tunnel and field production were not possible. The main benefit for high tunnel production of blueberries appears to be risk management (protection from adverse weather), but quantifying this would require long-term studies.
Impacts
Important new knowledge generated as part of this project includes a better understanding of how high tunnels modify the microclimate. The perception has been that high tunnels heat up during the day and retain that heat at night, providing freeze protection to the crops inside the tunnels. We found that high tunnels heat up quickly during sunny days, but the heat is not retained at night. The minimum temperatures inside high tunnels may actually be lower than outside, especially on clear nights. Radiative heat loss and the small air volume of high tunnels combine to produce rapid cooling of the air in high tunnels. Our finding that tunnels do not provide freeze protection is important, because many potential crops for high tunnel production are susceptible to freeze damage. The use of propane heat can be an effective, but expensive method to warm high tunnels at night. Additional study of freeze protection and supplemental heating in high tunnels is necessary. High tunnels were found to speed up vegetative and reproductive development of blueberries. Tunnels were effective at advancing the spring harvest of highbush blueberries and the summer harvest of floricane blackberries and raspberries. Tunnels also extended the season of autumn-producing primocane blackberries and raspberries. Overall, tunnels advanced spring production and extended fall production of blackberries and raspberries, increasing total harvest and berry size. Without supplemental heat, spring production was advanced 2.5 weeks. The plants required supplemental heat to prevent crop damage. When ambient temperatures dropped below -5 C the heating system did not protect the crop. Economic analyses demonstrated greater investments and costs for tunnel production, the increased marketing season, spreading and reducing seasonal risk, and managing labor force, the opportunities for tunnel berry production appear. The best approach may be for some production tunnel and field production of spring/summer floricane genotypes with a portion of autumn tunnel production. Selection of genotypes specifically for advanced spring production and extended autumn production of blueberries, blackberries, and raspberries is needed. Horner farms, a commercial organic blueberry grower cooperating on this project, has learned how to use high tunnels for the protection of their crop. They have been able to protect their crop from freezes by using propane heaters inside the tunnels, while the high tunnels also have been valuable in protecting the crop from hail. In tow of the three years of this research, field-grown blueberries were severely damaged by adverse weather conditions, while the high tunnels provided protection to the plant grown in them. This project has improved the infrastructure at the University of Georgia and the University of Arkansas. Upon completion of the research, the high tunnels in Georgia became an integral part of the organic teaching program, assuring that these students will get hands-on experience with high tunnels. The tunnels in Arkansas will be used for future research into high tunnel production of small fruits.
Publications
- Aselage, J. and D.T. Johnson. 2008. Chapter 39: From IPM to organic and sustainable agriculture, pp. 489-505. In E.B. Radcliffe, W.D. Hutchison and R.E. Cancelado (eds.), Integrated Pest Management, Cambridge University Press.
- Ogden, A.B. J. Kim, C.A. Radcliffe, M.W. van Iersel, L.A. Donovan, and A. Sugiyama . 2010. Leaf and bud temperatures of southern highbush blueberries (Vaccinium corymbosum) inside high tunnels. Acta Hort. (in press).
- Ogden, A.B. and M.W van Iersel. 2009. Southern highbush blueberry production in high tunnels: environmental conditions, development, yield, and fruit quality. HortScience (in press).
- Rom, C. R., M.E. Garcia, D. T. Johnson, J. Popp, H. Friedrich, and J. McAfee. 2009. Organic Production of blackberries and raspberries in high tunnels. Acta Hort. (in press).
- Johnson, D, B. Lewis, C.R. Rom, H. Friedrich, R. Bryant, and Maciej Pzsczolkowski. 2009. Organic fruit production needs and pest management practices in the southeastern united states. Acta Hort (in press).
- Haywood, B. 2009. Evaluating production budgets to determine best management practices for out-of-season high tunnel organic blackberry production. M.S. thesis, University of Arkansas, Fayetteville.
- Ogden, A.B. 2009. Organic southern highbush blueberry production in high tunnels. M.S. thesis, University of Georgia, Athens, GA. Krewer, G., C. Horner, R. Horner, E. Andrews, M. van Iersel, A. Ogden, M. Rieger, M. Tertuliano, and B. Mullinix. 2009. Evaluation of high tunnels for organic southern highbush production in South Georgia. Proc. Southeast Blueberry Conference (G. Krewer, editor), p. 26-31.
- Friedrich, H. C.R. Rom and M.E. Garcia. 2008. Sustainable Blackberry Production. Proceedings of the 27th Arkansas-Oklahoma Horticulture Industries Show (CD-Rom, digital publication)
- Johnson, D. 2009. Fruit insect alerts for May and early June. Arkansas Fruit and Nut Newsletter 5(3): 4-7.
- Johnson, D. 2008. Conventional insecticides for brambles 2008. Arkansas Fruit and Nut Newsletter 4(1): 9.
- Johnson, D. 2008. Organic insecticide options for brambles 2008. Arkansas Fruit and Nut Newsletter 4(1): 10.
- Ogden, A., J. Kim, C. Radcliffe, M.W. van Iersel, L. Donovan, and A. Sugiyama. 2009. High tunnel microenvironment affects leaf and bud temperatures of southern highbush blueberries (Vaccinium corymbosum L.). Scientific program, GreenSys 2009, p. 71-72. (abstract)
- Ogden, A. and M.W. van Iersel. 2008. Predicting nighttime low temperatures in unheated high tunnels. HortScience 43:1292. (abstract)
- Ogden, A., G. Krewer, E. Andrews, and M. van Iersel. 2008. Benefits of high tunnels for Southern highbush blueberry production include frost protection and early, large yields. HortScience 43: 1086-1087. (abstract)
- Ogden, A. and M.W. van Iersel. 2008. Predicting night-time low temperatures in unheated high tunnels. 2008 International meeting on controlled environment agriculture. Advances in research and design in CEA facilities, p. 61. (abstract)
- Vincent, C.I., M.E. Garcia, and C.R. Rom. 2009. Comparisons of growing degree unit models for primocane-fruiting blackberries. HortScience 44: 1001. (abstract)
- Friedrich, H., C.R. Rom, J. McAfee M.E. Garcia, D.T. Johnson, J. Popp, and C. Vincent. 2009. Performance of high tunnel organic blackberry and raspberry. HortScience 44:1114. (abstract)
- Rom, C.R., H. Friedrich, J. McAfee, E. Garcia,D. Johnson, and J. Popp. 2008. Early performance of organic managed floricane and primocane blackberries and raspberries grown in high tunnels for extended season. HortScience 43:1228. (abstract)
- Rom, C.R., H. Friedrich, J. McAfee, H. Choi, M. E.Garcia, D.T. Johnson, and J. Popp. 2008. The potential for extending the harvest season of organic brambles in the upper mid-south using high tunnels. HortScience 43:610. (abstract)
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Progress 07/15/07 to 07/14/08
Outputs
OUTPUTS: Results of this project have disseminated to diverse audiences in presentations and publications, as well as field tours of the trial planting. Presentations were made at a regional producer conference, the Oklahoma-Arkansas Horticulture Industries show. Presentations were made at the Southern Region of the American Society for Horticultural Science (published abstract), and at a national horticultural science meeting, the 2008 Annual Meeting of the American Society of Horticultural Science (three published abstracts), and an International Controlled Environemnt Agriculture meeting (published abstract). A presentation was made at the International Society for Horticultural Science Symposium on Organic Fruit Production in conjunction with the World Congress of the International Federation of Organic Agriculture Movements in Modena, Italy, with a report of preliminary observations published. A field day for regional producers was held in Arkansas in November 2007, with a field tour of the plot. The Arkansas research plot was toured by the Student Organic Farm Project - GroGreen, of the University of Arkansas. Three different academic classes have toured the Arkansas research trial. The University of Georgia research plots have been toured by students in the organic certificate program and the Horticulture Graduate Stiudent Association Master Gardeners have toured the plantings in both Arkansas and Georgia, and assisted with data collection. PARTICIPANTS: Hector German Rodriguez and Brittany Haywood have joined the team at the University of Arkansas. Mr. Rodriguez is a PhD student and Ms. Haywood is an MS student in the Department of Agricultural Economics and Agribusiness of the University of Arkansas. They will assist in the econmic assessment of small fruit production in high tunnels. At the University of Georgia, graduate students Carrie Eaton, Jongyun Kim, and Anna Sugiyama cooperated with the team members to study leaf, flower, and soil temperature fluctuations in detail. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Two project modifications have been made in Arkansas during this reporting period. The floricane fruiting blackberry cultivar Apache did not establish well, and in the time since the proposal of this project, has lost commercial favor. It has been replaced with Ouachita and those plots are 1 year behind other cultivars in development. The second modification is in the primocane fruiting studies. In an effort to delay flowering and fruiting, and to create harvest synchrony, primocane fruiting genotype plots have been subdivided for pruning studies used to delay flowering and fruiting.
Impacts
Research in Arkansas has focused on blackberry and raspberry production in high tunnels. As it takes two to three years for a newly planted blackberry and raspberry field to reach productive maturity, the full output and impact of the project is yet to be seen. The data developed from this project, and the demonstration and workshops associated with the project have led to growers planting organic blackberries and the installation of high tunnels. Growers who have recently planted organic blackberries and installed high tunnels have not yet achieved production. A one-day organic fruit production workshop and field day was held in November 2008, with a major emphasis on high tunnel bramble production. Over 100 growers and Extension agents, from Oklahoma, Missouri and Arkansas, were in attendance. Evaluation feedback was enthusiastic and attendees requested more organic workshops. Efforts in Georgia focus on blueberry production in high tunnels. As part of this research several important constraints for blueberry production in high tunnels have been identified. Early blueberry yields necessitate early flowering, and flowering in high tunnels may occur during a period when freezing temperatures are common. We have found that high tunnels by themselves provide little or no protection against freezing temperatures, but the use of high tunnels makes it feasible to use heaters in the high tunnels to prevent freezing damage. Pollination is another important issue. Because flowering may occur before there is much activity from natural pollinators or honey bees, we have used bumblebees for pollination. However in 2008, bumble bee colonies used in both North and South Georgia were not very active, resulting in poor fruit set. Thus more effective pollination methods would be beneficial. Lately, market access is a critical issue. High tunnels may be used for the early production of organic blueberries. However, packing sheds in South Georgia do not open early enough in the year to handle the earliest blueberries from high tunnels. Since most of Georgia's blueberry production is in areas of Georgia with a small local market, the lack of marketing options for early season blueberries is a serious problem.
Publications
- Rom, C.R., H. Friedrich, J. McAfee, H. Choi, M. E.Garcia, D.T. Johnson, and J. Popp. 2008. The potential for extending the harvest season of organic brambles in the upper mid-south using high tunnels. HortScience (accepted for publication, Jan 2008).
- Friedrich, H., C.R. Rom, and E. Garcia. 2008. Establishing and managing sustainable and organic blackberries and raspberries in high tunnels. HIS Proceedings January 4-5, 2008, Tulsa OK
- Ogden, A. and M.W. van Iersel. 2008. Predicting nighttime low temperatures in unheated high tunnels. HortScience 43:1292. (abstract)
- Ogden, A., G. Krewer, E. Andrews, and M.W. van Iersel. 2008. Benefits of high tunnels for Southern highbush blueberry production include frost protection and early, large yields. HortScience 43:1086-1087. (abstract)
- Ogden, A. and M.W. van Iersel. 2008. Predicting night-time low temperatures in unheated high tunnels. 2008 International meeting on controlled environment agriculture. Advances in research and design in CEA facilities, p. 61. (abstract)
- Rom, C.R., M.E. Garcia, D.T. Johnson, J. Popp, H. Friedrich, and J. McAfee. 2008. Organic Production of Blackberries and Raspberries in High Tunnels. Acta Hort (accepted for publication).
- Rom, C.R., H. Friedrich, J. McAfee, E. Garcia, D. Johnson, and J. Popp. 2008. Early Performance of Organic Managed Floricane and Primocane Blackberries and Raspberries Grown in High Tunnels for Extended Season. HortSci. 43:1228. (abstract)
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Progress 07/15/06 to 07/14/07
Outputs
OUTPUTS: The focus of our activities during year 1 has been on construction of the high tunnels in Georgia and Arkansas and on getting the small fruit crops established in the high tunnels and control plots. Six high tunnels and two control plots with two cultivars of blueberries were established on the University of Georgia Horticulture farm. Blueberries were planted in the fall of 2006, allowing for small yields in the spring of 2007. A 2/3 acre high tunnel with blueberries was established at Horner Farms in Homerville, GA, almost 2 years ahead of schedule. Here the high tunnel was erected over an existing bearing blueberry crop, allowing for significant yield in the spring of 2007. However, this 2/3 acre tunnel was not finished until early February, too late to see maximum effects of high tunnels on achieving early yields. However, we were able to collect valuable data on the use of high tunnels for freeze protection. Flower development and yield data were collected at both sites.
Three high tunnels with three floricane and three primocane cultivars of both blackberries and raspberries were constructed at the University of Arkansas and yield and berry size were determined in the fall of 2006. Plant survival was poor in the summer of 2006 due to uncharacteristically hot weather and some of the plants had to be replaced in March 2007. In both Arkansas and Georgia, the effects of high tunnels on environmental conditions were studied. An additional objective of this project is to do economic analyses of these high tunnel production systems, but we do not have sufficient data yet to do so. The project goals and opportunities for high tunnel alternate season production of blackberries were presented at talks at the Arkansas-Oklahoma Horticulture Industries Meeting and Trade Show (January, 2007), and at a blackberry production workshop (June, 2007).
PARTICIPANTS: Andrew Ogden, a MS graduate student, has worked on the blueberry project in Georgia. Greg Cousins, an undergraduate student, has helped as well. This has provided valuable research experience for both.
Impacts
In Athens, GA, we studied the effect of the timing of high tunnel closure on blueberries. Tunnels were covered with plastic on December 16, January 2, or January 20 and 'Emerald' flowered January 8, 11, and 21, respectively. 'Emerald' in the outdoor plots flowered January 26. Despite earlier flowering in high tunnels that were closed earlier, blueberries in all tunnels ripened at the same time, starting in late April, with harvest continuing through May. Early yields were similar in all tunnels, irrespective of when they were closed. Throughout May, yields were higher in tunnels that were closed later, resulting in highest yields in tunnels that were closed on January 20. Due to the Easter freeze of 2007, all outdoor fruit was lost. Freeze protection in the tunnels was achieved with propane heaters. The high tunnel at the commercial farm in South Georgia was not finished until the second week in February, and its maximum effect on fruit ripening was not seen.
Nonetheless, fruit ripening in the high tunnel was advanced by about one week. The data in South Georgia provided valuable information regarding the effect of high tunnels on microclimate. Without heat, the closed tunnels increased air temperature by about 2 F compared. During the 17 Feb. freeze the outside temperature dropped to 22 F and the inside temperature to 31.5 F. The high tunnel was heated with just one 155,000 BTU propane heater. The 17 Feb. freeze destroyed about 50% of the advanced flowers outdoors, but there was little damage in the high tunnel. The tunnels also were effective for preventing damage during the Easter freeze. Fruit yields were greatly increased by use of the tunnels. Outdoor 'Millenia' yield was 1.03 lbs versus a tunnel yield of 3.09 lbs per bush. Outdoor 'Star' yield was 1.41 lbs versus a tunnel yield of 2.05 lbs per bush. The objective of the research done in Arkansas was out-of-season organic blackberry and raspberry production. Although no yields were
expected in the year 1, because of the growth of the primocane fruiting blackberries, yield data were collected. High tunnel yields were increased in the range of 400% ('Prime-Jim') to 77% ('Prime-Jan') with an average increase of 65% compared to outdoor plots. Part of the yield increase was due to increased berry size. High tunnels also extended the season of flower formation and harvest. While yields outdoors started decreasing in the middle of October, yields in the high tunnels did not peak until the end of October. We have found in both Arkansas and Georgia that the effect of high tunnels on the microclimate is not easy to predict. Although night-time temperatures inside the high tunnels are generally higher than outside, on some nights the tunnels are cooler. We plan to look at the use of row covers to provide additional, and more economical, freeze protection.
Publications
- Rom, C.R., H. Friedrich, and J. McAfee. 2007. Organic Fruit Research Update: Possibilities and Challenges. Proceedings of the Arkansas-Oklahoma Horticulture Industries Show. January, 2007.
- Ogden, A., G. Krewer, and M.W. van Iersel. 2007. High tunnels trigger earlier flowering and fruit set in organic southern highbush blueberry. HortScience 42:860. (abstract)
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