Final Report for LS12-250
The goal of this project was to develop high tunnel production systems for blackberries and raspberries that may compliment a field system by extending the harvest season, expanding cropping, improving fruit quality, and be especially adaptable to sustainable and organic production systems. Two field studies using high tunnel technologies and modifications to tunnels were conducted to determine how the technologies may fit into sustainable and organic fruit production systems in the south. The two studies used high tunnels (HT) to 1) advance floricane blackberry harvest and blueberries, and 2) extend the harvest season of primocane fruiting blackberries and raspberries cultivars. Preliminary studies indicated the potential for both. Tunnels were modified to include A) tunnels within tunnels (TnT) around the fruiting plants, B) total screening of the tunnels to exclude insect pests, and C) an overhead micro-fogger system to reduce summer temperatures. Additional studies on the use of shade to delay flowering and fruiting in primocane fruit blackberries were conducted with assistance of the SARE Young Scholar Enhancement (YSE) supplemental grants. Project activities focused on organic field experiments, organic insect pest management practices, developing and testing interactive enterprise budgets for blackberries, raspberries and blueberries and the grower sustainability assessment, Sustainable Blackberries and Raspberries: A Self-Assessment Workbook for Growers, in addition to sharing project results through various outreach and extension methods.
In the experiment for floricane fruiting blackberries, HT and TNT treatments reliably led to earlier harvest, larger fruit, and higher quality fruit compared to open field plots. TNT provided an extra layer of frost protection and heat retention however issues with inadequate bee pollination, which requires additional study, prevented any significant earlier harvest. Establishment of the organic blueberry trial was problematic, however, project goals were met with a movable HT were placed over an established adjacent organic blueberry variety trial in 2015. HT or TNT advanced blueberry harvest from 0 to 11 days depending on the cultivar. Although HT blueberry yields tended to be higher than FD the difference was not significant, due to a limited number of replication. In the experiment for primocane blackberries, cultivars PrimeArk 45, Prime-Ark Traveler, and APF 205, yielded 2-3 times higher in HT compared to FD and had significantly higher marketable yield. HT and TNT treatments were harvest from one to 5 weeks longer than FD plots when cold temperatures/freezes stopped production. The raspberry study was discontinued in 2014 due to significant plant death. The effects of shade on primocane blackberries in HT was investigated by SARE YSE interns in field and greenhouse studies. In primocane blackberries, shading in mid to late June and mid-July did tend to delay flowering and fruiting, however, it also tended to reduce cropping. In raspberries however shading increasing fruit yield. A micro-mist system was tested on its potential to lower HT temperature and bumble bees were monitored on their habits and frequency of visits to flowers under TNT.
Over the past 3 years broad mites and spotted winged drosophila (SWD) emerged as key pests that threaten sustainable bramble production. Exclusion insect screen was places on HTs to protected fruit from SWD but the screen offers little protection against mites. Aphids and two-spotted spider mites are two key pests in HT. Various approaches were used to control these pest, organically.
Three interactive sustainable berry budget tools were developed for blackberry, blueberry, and raspberry, available at www.cars.uark.edu. These tools estimate costs and returns for field and high tunnel production. Berry producers can create complete production budgets for their operation and can perform breakeven, sensitivity and risk analyses to make better production and marketing decisions.
Project information on organic HT production considerations, insect pest management, economic potential and farm sustainability was extended to current and potential growers, students, and extension educators through presentations at regional annual winter conferences including the OK-AR Horticulture Industry Show in 2013 and 2015, the Missouri Organic Association conference in 2013-2015, a three workshops on high tunnel fruit production with accompanying field tours, a blog, newsletters and national professional society meetings for horticulture, entomology and agricultural economics.
The purpose of this project is to extend the sustainable production of summer berries using HT technology to achieve earlier spring harvest of blueberries and blackberries, and to allow for an extended autumn production of new primocane blackberries and raspberries. The goal of the project is to develop an environmentally and economically sustainable organic fruit production systems combining HT production with traditional FD production and providing for further expansion of organic crop production in the southern region.
The specific project objectives were:
- To develop High Tunnel (HT) production systems for season extension of organic high value fruit crops for the southern region.
- To develop and test pest management strategies for organic HT crop production systems adapted to the southern region.
- To estimate economic models and to create decision support tools that help producers to manage production systems for profitability considerations
- To extend the knowledge acquired through the production, pest management, and economic analyses into a multi-dimensional educational, outreach, and extension program.
The purpose of this project was to employ and advance HT technology to extend the production of summer berries to achieve earlier spring harvest of blueberries and blackberries, and to allow for an extended autumn production of primocane blackberries and raspberries. Blueberries and blackberries, traditional southern fruits, are perennial crops requiring year-around management, however, the harvest and market season is confined to a few weeks during mid-summer. Raspberries are not well adapted to the hot humid south because the flowers and fruit are not tolerant of high summer temperatures. New cultivars of fall-bearing blackberries and raspberries have limited adaptability to the south because they flower during summer heat, reducing fruit-set. Later blooming cultivars are also not well adapted because fruit mature after expected seasonal frosts. HT offer several potential advantages for sustainable production including to: 1) advance the spring season of blueberries and blackberries, extending the autumnal harvest season, and allowing raspberries to fruit during more favorable temperatures; 2) expand and increasing harvest and market season, product quality, and therefore crop value; 3) protect fruits from frosts, hail, and damaging rain or sunburn resulting in reduced yields as experienced in FD; 4) exclude damaging pests; 5) exclude rain to minimize wet foliage, reducing disease outbreaks and pesticides use, 6) extend the usefulness of pest management tactics such as pesticides or released beneficials, and 7) conserve water. HT have been used for summer berry production in other regions to prevent winter injury in cold environments or to provide an environment to grow crops which cannot otherwise be possible, often to provide sufficient heat to mature a crop.
For several years, University of Arkansas co-PIs have led efforts to develop production and pest management practices for organic high tunnel small fruit production in the southern region. Many achievements have been made towards developing sustainable organic high tunnel fruit production system, many challenges still remain especially with pest management. Our earlier research of these fruit crops in this region has demonstrated the potential for HT production to compliment FD production. One of our goals of this current project was to identify practices to make HT production more functional and profitable.
High tunnel and open field production of berries are considered as distinct production systems. The components of the system are the crops (e.g. blackberries, blueberries, raspberries), the specific cultivars used for each crop, the environment (HT and FD), the HT and FD environmental modifications, appropriate horticultural management required for each environment, and the pest management required for each crop, cultivar and environment. The traditional FD production of berries results in year-long maintenance for a seasonal 4-week harvest period. However, HT provide both an alternative and a compliment to FD production, extending the production season to capture early season markets. HT may be the only system for production of some crops such as raspberries in parts of the southern region. HT may provide for a crop when the environment limits or eliminates a FD crop due to adverse or extreme conditions. However, in many years, farmers will benefit from HT + FD production as a means of mitigating and spreading risk, spreading labor requirement, spreading marketing, and spreading seasonal cash-flow. This project was designed to improve the environmental and economic sustainability of summer berry production in the southern region using HT technology in southern fruit production with special applications to organic production, and to provide educational resources allowing growers to adopt HT technologies, to make economic-based decisions, and to evaluate their progress towards sustainability with their management tactics.
In addition to field research on production and pest management practices, four tools were developed to assist growers in decision making processes. Three interactive economic budgets were developed for blackberry, raspberry and blueberry crops. These interactive tools are unlike any previously available in the state or the region. The berry interactive decision support tools are not only user friendly but also encompass budgeting, economics and risk component abilities to do actual and what if analyses in ways berry producers cannot do with available traditional budget tools. Since an extended season for some crops could assist producers in capturing a larger market share, especially early and late season when premium prices are paid, high tunnels capabilities were also included. These features allow comparisons among different production systems that may assist berry producers to make better investment decisions. These interactive tools will allow berry producers, extension agents, policy makers and educators to perform and customize economic assessments of production practices before they are adopted in their operations.
The final tool to be developed was a blackberry and raspberry grower sustainability self-assessment. This tool was modeled after the Ozark Mountain Vineyard Sustainability Assessment Workbook (co-PI Johnson, lead). The self-assessment helps growers identify areas of their production or farm that would benefit from sustainability improvements. All of these tools are free and available on the Center for Agricultural and Rural Sustainability website.
- To develop High Tunnel (HT) production systems for season extension of organic high value fruit crops for the southern region.
HT were compared to FD systems in 2 studies at the Arkansas Agricultural Research and Extension Center, in Fayetteville AR. All production systems were managed in a sustainable system for USDA NOP organic certification. Land for the project had been under organic management since 2005. Plantings were established in 2012. Prior to planting beds were amended with urban compost and composted chicken litter. All plants were planted through 2mil geotextile landscape fabric mulch as a weed barrier to reduce weed competition and for water conservation. Row edges and walk rows were covered with woodchip mulch. After one growing season, the geotextile mulches were removed and replaced with woodchip mulch.
Study 1) HT versus FD spring/summer production of blueberries and blackberries; and,
Study 2) HT versus FD production of autumn harvested primocane-fruiting raspberries and blackberries.
In study 1, ‘Earliblue’ blueberry and early season floricane fruiting blackberry ‘Natchez’ were planted in open field and in a high tunnel (Farm Tek, Clearspan) 85’x28’. Blueberry survival rate in the open field with highly mineral soils under organic conditions was very low, thus plots were replanted in 2013 and some plant replacement again 2014. Because of low survival and poor establishment in field plots and plant age differences, in 2015, a movable HT (MHT) was placed over an established, six-year-old, organic blueberry variety trial to test the potential for early cropping and identify potential yield advantages. Two replications of high tunnel, TNT and open field treatments were placed over two plants each of six blueberry cultivars: Aurora, Blue Crop, Chandler, Draper, Liberty, Ozark Blue.
A substudy of HT modification was conducted to increase heat unit accumulation and conservation. Plots within tunnels, a Tunnel-in-Tunnel (TnT) covering plants was constructed and covered with geotextile material, when the HT were closed in winter to begin advancing spring production. In Study 1, tunnels were close approximately 15-Jan to 1-February to trap and conserve solar heat and drive degree-day accumulation. Tunnels were closed when ambient temperatures were below 50F and opened when temperatures exceed 50F and the sun is shining. Boxed bumblebees (Biobest, USA) were deployed in tunnels and TNT for pollination. When expected daily low temperatures continuously exceeded 50F, sides and doors of tunnels were opened continuously. After harvest, sides and doors remained open. Over the years of the study additional modifications were made to the TNT to improve and optimize the environment within the TNT.
In study 2, blackberries (cultivars Prime-Ark® 45, Prime-Ark® Freedom and APF205, advanced breeding line) and raspberries (cvs Nantahala, Autumn Bliss and Josephine) were planted in open field and in a high tunnel (190x20’, Clearspan, Farm Tek, Dyersville IA) in 2012. Plants were spaced at 2ft between plants and 8 ft between rows. Tunnels remained open during the summer and closed during autumn when temperatures were below 50F. A substudy of the influence of 25% shade on temperature modification and cropping was conducted. TnT structures covered with 25% shade were placed over replicate plants within the tunnels during the flower development and bloom period (approximately 25-July to 1-Sept) and removed when daily high temperatures were below 88F. When seasonal killing frosts (30F) occurred, no additional protection was provided to FD plots. However, frost protection was provided in tunnels as necessary if the estimated crop protected would exceed the cost of the frost prevention treatments until it was determined that the cost of protection exceeded the estimated value of the crop within the HT and/or TNT.
A substudy of HT modification was conducted in ‘Prime-Ark® 45’ to increase heat unit accumulation and conservation in the late fall. Tunnel-in-Tunnel (TnT) covering plants were constructed and covered with 6 mil polyethylene plastic in the fall to protect crops from frost and accumulate additional heat units extending autumn production. Tunnels were closed when ambient temperatures were below 50F and opened when temperatures exceed 50F and the sun was shining. Frost protection was deployed within tunnels when temperatures declined below 30F and the crop load warranted it.
All studies were designed with six replicated plots (n=6) of each cultivar in each system (HT vs FD). Statistical analyses were by analyses of variance comparing the main effects of system. Growth and performance variables were measured including time of first bloom and full bloom, time of first harvest and peak harvest, weekly harvest, average berry size at each harvest, berry quality (soluble solids and firmness/leakiness), cane number per plot, cane height, etc. Meteorological conditions of air and soil temperatures, light flux, relative humidity, and soil moisture. Precipitation was measured and water from irrigation was metered in order to maintain plant-row soil at 30-50cbars soil water tension during the growing season.
Objective 2. To develop and test pest management strategies for organic HT crop production systems adapted to the southern region.
Scouting: HT, TNT and FD plants and fruit in studies 1 and 2 described above were scouted on a weekly basis for pests (raspberry crown borer, rednecked cane borers, plum curculio, stink bugs, Japanese beetles, tarnished plant bug, mites, aphids and white flies) and diseases (fireblight bacterial blight, anthracnose, powdery mildew, and root rot) to identify genotype (crop and cultivar) and production system (HT vs. FD) differences on changes in mean pest densities and mean disease pressures over time
Pest Management: Foliar and fruit pests were monitored throughout the season and control tactics were used as needed. In early May 2015, AzaDirect (Azadirachtin) was applied to HT and field primocane blackberries to control aphids and strawberry rootworm beetles or flea beetles. A strong blast of water was applied to the very dense ‘Natchez’ blackberry canopy inside the tunnel-in-tunnel to remove aphids and sooty mold. On 11 June 2014, released C. maculata larvae (1,090) and adults (538) but on 18 and 22 June collected 10 leaves per plot from aphid-infested terminals but found only one C. maculata on these plants. On 2 July 2015, predatory mites, N. californicus and N. cucumeris, and aphid parasitoid, Aphidius colemani (Rincon-Vitova, Ventura, CA) were released in the smaller HT. On 12 June 2014 and 15 July 2015, released on aphid-infested terminals larvae and adults of predatory beetle, C. maculata (Eric Riddick, USDA-ARS Stoneville, MS). On 9 July 2015, 21 Scymnus creperus larvae (Scott Creary, IPM Labs, Inc., Locke, NY) were released on aphid-infested terminals. On 4 June 2014, ProtekNet 25 g/m2 exclusion insect netting was installed along open sides and ends of the high tunnel to determine what pests would be excluded. This screen was noted as too flimsy and developed holes that required constant patching. In June 2015, a sturdier (7 yr lifespan) and wider mesh 80 g/m2 ProTekNet exclusion insect netting replaced the 25 g/m2 netting. The insect netting remained in place on the HT throughout the winter into the 2016 growing season. Fruit growers were alerted about pests and management practices via the University of Arkansas Fruit/Nut Pest Management web page and timely email distribution of 20 issues of the Arkansas Fruit and Nut News (Link).
Objective 3. To estimate economic models and to create decision support tools that help producers to manage production systems for profitability considerations
As part of this project, blackberry, raspberry and blueberry interactive budgets were developed. These budgets allow comparisons among total costs, gross returns and net returns to assist berry producers to make better planning and financial decisions. The interactive budgets were created in Microsoft Excel using VBA programming interfaces. Producers can estimate several budgets by using default cost values, by entering their own production values or by combining both entry systems.
In these interactive budgets, the user enters their production data including plant density, yield, markets - fresh and/or processed market, sale prices, labor wages, interest rate, inflation rate, trellis system information, irrigation information, machinery and equipment information and high tunnel dimensions (if any); then the budget is calculated automatically. The budgets estimate variable operating costs, fixed costs, total costs and expected total net returns. When user modifies an activity, the budgets automatically recalculates total cost, gross returns and net returns per year.
In developing these budgets, individual costs were based on 2015 prices and University of Arkansas (UA) recommended practices. Berry fields were assumed to receive irrigation. Each production system had the same insect, disease and weed management. Real estate taxes and land cost are optional. Cost estimates were calculated for each year, with year zero as the year before planting (i.e., soil preparation) and year one as the planting year. Costs in year zero include land preparations, leveling the field, fertilizing the soil, etc. Planting, controlling weeds, and installing irrigation, trellis (if any), and high tunnels (if any) systems are some of the costs in the first year.
Cost information was divided between variable and fixed costs of production. Variable cost include fertilization, rental of machinery and equipment, ground cover, nutrient/foliar analyses, pest management, labor, other expenses, and harvest. Fixed costs include: management costs, real estate costs, and amortization of machinery, trellis, irrigation and high tunnel systems.
The user can enter tailored information or use the “demos” provided in each interactive budget. Demos reset the budgets to the default values. Once the information is entered and validated, the model runs and displays a detailed budget for each year including soil preparation, planting and all production years. Results are displayed in net present values (NPV). Presenting the results in this way helps the producer decide whether or not to undertake the project under those specific conditions/assumptions. Each budget has an economic summary that is displayed in tabular and graphical forms. Results are presented in terms of cumulative total costs, total returns, and net returns.
For all operations and input prices outlined in this budget, it was assumed that the blackberry, raspberry and blueberry crops are under near to optimal management and that all recommended practices would be followed. The costs were calculated as if the producer started with a open field and followed the budgeted pattern. Assumptions regarding yields, interest rates, amortization (for tunnels, trellis systems and irrigation systems) as well as input prices and berry prices were based on economic and production conditions experienced during the project field experiments.
Objective 4. To extend the knowledge acquired through the production, pest management, and economic analyses into a multi-dimensional educational, outreach, and extension program.
Project results were disseminated to growers, farmers’ market managers, consultants, extension agents and NRCS field staff through multiple outlets and media. A project blog http://hightunnelberries.uark.edu/ was established in year 1 as served as portal for project information, news, an archive for presentations, videos and other pertinent information. Blog posts were divided among project leaders to provide relevant information on production, season extension, pest management, economics and outreach activities. Project information and presentations were also made available on the Center for Agricultural and Rural Sustainability website (CARS), http://cars.uark.edu/ourwork/Specialty-Crop-Production-and-Marketing/hightunnelorganic_fi.aspx. Additionally Arkansas fruit growers were alerted to pests and management practices via the University of Arkansas Fruit/Nut Pest Management web page and timely email distribution of the Arkansas Fruit and Nut News (Link).
Three workshops and field days occurred in years 2 and 3. In Feb, 2013, a high tunnel construction workshop was held in Clarksville at the Fruit Research Station. Information was shared on types of tunnels, materials and tools needed, and modifications to tunnels. Approximately 40 participants attended from AR and OK. A June 2013 a workshop and field tour in Fayetteville provide information about movable HT, irrigation, fruit production, insect management and NRCS resources. The field tour highlighted three types of high tunnels that are used on the UA farm – FarmTek, Haygrove, and Four Season Movable tunnel. Approximately 50 people participate from AR, MO and OK. A May 2015 workshop and field tour in Fayetteville presented project results and information including crop management, HT construction, maintenance and modifications, seasonal operations, (IPM practices, nutrition, etc.), interactive economic budgets and the sustainability workbook. The field tour showcases high tunnel fruit in production including blackberries, blueberries, strawberries and grapes. About 50 people attending the workshop with 35 participants receiving a copy of the Sustainability workbook. In 2016, 70 participants of a Blackberry production workshop organized by a partner group at UA received the Sustainability workbook after a presentation on the project.
In conjunction with the Arkansas-Oklahoma Horticulture Industry Show (HIS) in Fort Smith, AR in 2015 the fruit production track focused on providing in-depth information on production, pest management and economics of high tunnel berry production. Each of these talks had from 10-20 people in the audience. Project presentations were made at other regional annual grower meetings including the Missouri Organic Conference (2014, 2015), Southern SAWG (2014, 2015), and National and Southern region ASHS conferences, the North American Raspberry and Blackberry Association conference, and the NCCC212 Small Fruit and Viticulture Research meetings. At the Missouri Organic Association conference, a half-day session featured project co-PIs and their respective work in high tunnel fruit production. Each of these sessions had 25-35 people in the audience. These presentations were made available on the project blog and on the CARS website. Scientific results were presented at professional societies including the American Society for Horticultural Science, the American Entomological Society, and the Agriculture and Applied Economics Society. The tunnels were used for formal class instruction at the University of Arkansas in the Principles of Horticulture Class, Fruit Production Science class, the Insect Behavior Class, Environmental Economics class, and Sustainable and Organic Horticulture Production. Additionally, several students participated in this project throughout its duration. Three horticulture grad students, 5 undergraduate students, and 2 entomology students participated in studies associated with the project or were employed by the project and worked in the tunnels. One of the students completed an honors thesis related to the project, presented papers at regional and national meetings, won awards for the work, and published 2 articles in the University of Arkansas undergraduate research publication, Discovery (Caillouet et al., 2016 a and b).
Information generated through this project and previous high tunnel berry projects contributed to the development of Sustainable Blackberries and Raspberries: A grower self-assessment. This grower sustainability check list was designed to assist growers in tracking farm sustainability and identifying areas in their operation that may need improvements. The tool can be conducted on an annual basis and serves as a benchmark for sustainability improvements on-farm. The Sustainability Assessment workbook was based upon similar a tool created by our group (Ozark Mountain Vineyard Sustainability Assessment Workbook). Over 150 copies have been distributed to Arkansas, Oklahoma and Missouri growers. The workbook is available for download on the CARS website, the high tunnel blog and SARE.
Objective 1. To develop High Tunnel (HT) production systems for season extension of organic high value fruit crops for the southern region.
Study 1. Advance cropping of summer floricane blackberries with High Tunnels (HT) and Tunnel-in-Tunnel
(TNT) use compared to field (FD) production.
Natchez plants in HT and TNT treatments reliably led to a 2 to 2.5-week advance in bloom compared to FD plots in three years of this study. The advance in TNT, only, bloom however did not always translate to advanced harvest or higher yield. Excessive heat buildup and pollination issues may have contributed to lack of advanced harvest despite earlier flowering. In 2014 it was learned TNT reached hotter temperatures quicker than HT alone. Management practices were adjusted in subsequent years to minimize this issue from repeating and added bee boxes to TNT plots for pollination. In 2015 earlier blooms in TNT again did not translate to earlier harvests. In the Fall of 2015 we conducted an observational study on bee activity in the primocane study.
Compared to TNT and FD plots, berries in HT reliably had earlier and larger harvest. In 2014 and 2015, plots in HT were first harvested 2 weeks, and 2.5 weeks prior to FD plots, respectively. TNT and HT plots were first harvested at nearly the same time although TNT bloomed earlier that HT. In 2014, HT and TNT had twice as much yield as FD plots. In 2015, HT again produced twice as much yield and nearly three times the marketable yield as FD. In years with significant rain during the post bloom and fruit ripening season, FD fruit were damaged by precipitation while they were unaffected in the HT.
Study 1b. Advancing blueberry harvest with HT and TNT, compared to Field.
Organic blueberry establishment was difficult with attempts made in both 2013 and 2014 to establish plants, with limited success. Plants in open field plots experiences 100% death in both years due to a combination of issues including the heavy mineral soil, that although manipulated, limited establishment, and significant abnormal meterological conditions. In 2015, we took advantage of an opportunity to place a movable HT (MHT) on an established, six-year-old, organic blueberries variety trial to test the potential for early cropping and identify potential yield advantages. Two replications of high tunnel, TNT and open field treatments were placed over two plants each of six blueberry cultivars: Aurora, Blue Crop, Chandler, Draper, Liberty, Ozark Blue.
- Berries in HT numerically out-yielded field plots (45% increase), however yields were not significantly different
- Berries in TNT plots yielded significantly lower than other treatments, likely due to limited pollination by inadequate bee flight and visits to the blueberry flowers.
- Not all blueberry cultivars performed similarly. Some cultivars performed better in HT and other performed as well or better in open field conditions, indicating the need for variety trials for HT systems.
- Liberty showed significant response to HT treatment, yielding 1.4 x greater in the HT compared to the FD
- HT or TNT advanced first harvest date from 0 (Bluecrop) to 11 days (Chandler)
Study 2. Extend the harvest season of autumn primocane blackberries with HT, TNT, and shade treatments compared to the FD.
‘PrimeArk 45’ grown in HT had significantly greater total yield than FD plots from 2012-2015. Additional cultivars in 2015, Prime-Ark Traveler, and APF 205, along with ‘Prime-Ark 45, had increased yield in HT by 2-3 times along with increased marketable yield. In 2014 Fruit in the HT had an extended harvest period of approximately 1 week across both seasons compared to the FD before severe freezes (below 24oF) ended production. The TNT extended harvest an additional 2 weeks with additional freeze protection. In 2015 there was a killing frost on November 16. HT extended harvest for an additional week and TNT extended harvest for an additional 5 weeks until approximately December 21, 2015.
Effect of Shade on time of bloom and harvest
Three YSE apprentices and interns conducted project studies using shade cloth as a means of delaying the flowering and fruiting of primocane blackberries to avoid heat stress, and further capitalize on the use of HT to extend the season. Shading in mid to late June and mid-July did tend to delay flowering and fruiting, however, it also tended to reduce crop yields. An additional study of the effects of shade on growth, development, physiology and fruiting of blackberry was conducted. A preliminary greenhouse study indicated that shading earlier in the growth cycle and then removing shade had the potential for delaying flowering, and possibly increasing flowering, however, data were not significant. Shading as a means of delaying flowering and fruiting in primocane blackberries needs additional study. Some fundamental research on the timing of flower initiation and development is needed in order determine the appropriate times for implementing shading. Raspberries however, responded favorably to this shading strategy and resulted in increased fruit yield.
HT were screened which exacerbated high temperature issues. Each year of raspberry production showed a CVxlocation interaction. Autumn Bliss performed the best in HT and was the highest yielding CVxLoc treatment. Josephine and Nantahala both grew better in FD conditions compared to HT. Soil-borne diseases became a problem in the HT and the effects were most apparent in these two cultivars after HT were screened (for insect pest management) which increased temperatures. Autumn Bliss seemed to show more resistance to root rots and tolerance to summer temperatures. The Raspberry study was discontinued due to plant loss induced by a combination of root rots, severe mite infestation, and high temperatures inside the screened high tunnel. Although progress was made on this objective, it was not completed due to the experiment termination. The project, in combination with previous studies, has demonstrated there is good potential for HT raspberry production in the upper mid-south region, although additional studies are required to tune the system.
Although TNT advanced bloom, plants were not harvested earlier and sometimes had lower yields that HT or FD treatments. Based upon observation, our hypotheses was that the TNT created an unfavoreable environment for bumble bee flight or prevented adequate pollination and fruit set. To test the effect of the TNT environment on bee flight, bee activity was recorded in five minute increments at four plots per treatment, HT, TNT, FD. Activity was recorded at three discreet times throughout the day: 10:40 am, 1:00 pm and 4:00 pm. Bee activity was similar in HT and TNT at 10:40 am and 1:00 pm time frames, however during the 4:00 pm time, activity was significantly lower in TNT, 2 visits vs 9 visits, respectively. Continued research is needed to isolate the reason for a reduction in pollination and fruit set.
Overhead Irrigation and Misting to Reduce HT Temperatures
Over a two summer period, an overhead irrigation system was installed along the HT ceiling center purlin and tested to reduce HT air temperatures with evaporative cooling. In 2014, a micro-irrigation system was tested and demonstrated a proof of concept. When the irrigation system was started at 88F (31C) temperatures were reduced. Over a period of replicated days, continuous, or pulsed irrigation was tested and demonstrated a reduction in air temperature. However, the micro-sprinklers required significant water and resulted in plant foliage wetting. In 2015, the system was modified with micro-mist emitters and tested to reduce high summer temperatures in a screened HT without wetting the foliage. This addition was managed by the SARE Young Scholar intern and another horticulture student The cooling system effectively reduced temperatures to ambient, external temperatures after running just 1 hour. Although this system needs additional modifications and research is necessary, this was a proof of concept test demonstrating the potential for reducing high summer temperatures in a screened HT.
Objective 2. To develop and test pest management strategies for organic HT crop production systems adapted to the southern region.
Over the past 3 years broad mites and spotted winged drosophila (SWD) emerged as key pests that threaten sustainable bramble production. Broad mites are a new pest in Arkansas and the mid-South with outbreaks being reported in FL, IL, IN, NC, PA, and SC. The broad mite causes terminal leaf bronzing and cupping on primocanes and can kill terminals and new lateral shoots and flower buds, reducing fruit yield on floricanes and primocane production in late summer/fall. SWD has emerged across the country as a new pest threatening many soft fruits. Females lay eggs in ripe fruit which are often not detected until postharvest in the larval stage. Exclusion insect screen used on HTs protected fruit from SWD. Because of the microscopic size of broad mites the screen offers no protection against this pest. Mite-free plants at time of planting is required to eliminate the source of infestation.
Environmental changes created by high tunnels impact plant productivity but also significantly affect insect pests, biological control and diseases. Additionally, primocane production in HT is essentially a “new crop” with a new set of production and pest issues. Brambles grown in HT are often threatened by insect pest that thrive under the HT environment and do not affect open field production. Thus new pest management practices must be studied. Approaches we used to control these key pests are highlighted below.
In Study 1: As primocanes emerged in the HT in early spring, each year aphids fed and reproduced on terminals and adult strawberry rootworms, Paria fragariae, caused significant shot hole leaf damage. Neither pests were observed in the FD planting of blackberries. Azadirachtin was applied to infested plants which prevented further rootworm damage but aphids persisted. In June 2015 Surround WP kaolin clay was applied to whitewash new primocane leaves to stop further shot hole damage by P. fragariae and another flea beetle, Pachybrachis spp. The treatments demonstrated some efficacy but not complete control.
Early spring aphid feeding on terminals with flower buds subsequently caused poor fruit set and yields. In partnership with Eric Riddick (USDA-ARS, Stoneville, MS) several releases of predatory beetle, C. maculata, were made. In June 2014, native predators of aphids were found already in the HT including: immature praying mantids; adult syrphid flies; and two species of lady beetles, C. septempunctata, and the multicolored Asian lady beetle, H. axyridis. In April 2015, predator lady beetles, C. maculata, were again released on aphid-infested terminals but aphid-tending odorous house ants, Tapinoma sessile, prevented biological control by these beetles. However, 50% or more of these aphids were infested with a parasitic wasp, Aphidius colemani which increased to 100% parasitization of aphids by June 2016, likely due to overwintering A.colemani populations inside the HT. Some fruit was unmarketable due to aphid mummies (PIC). In June 2015, Riddick observed two wax covered predatory beetle larvae, likely Scymnus sp., in the HT that were not repelled or killed by aphid-tending ants. In July 2015, Scott Creary (IPM Labs, Inc.) sent Scymnus creperus predatory beetle larvae that were released on aphid-infested terminals in the HT. It was observed that aphid-tending ants did not attack these larvae. By mid-July six Scymnus larvae were still present and aphid numbers had dropped. In 2016, larvae of Scymnus were more abundant in the HT, feeding on aphids. This species may have potential for mass release for biological control.
The release of C. maculata did not reduce the aphid numbers because the aphid-tending odorous house ants repelled the predators. In May and June 2016, the ant bait Seduce (Certis USA, Columbia, MD) was sprinkled on the soil at the base of blackberry plants but did not reduce the number of odorous house ants or ant-tending of aphids. The efficacy of Seduce may be improved by mixing it with honey or sugar water to increase the attractiveness to this ant species. Additional work is needed to optimize control measures of the aphids.
SWD: In 2013, a portion of the HT with primocane fruiting blackberries and raspberries was screened with ProtekNet to exclude SWD from the production system. Across the years, screening provided the most effective prevention of SWD infestation less than 10% infestation. FD plots were treated with weekly applications of Entrust (spinosad) alternated with Pyganic (pyrethrum) and resulted in up to 90% SWD-infested fruit. Entrust usually reduced subsequent SWD fruit infestations but Pyganic did not. The fine mesh of the screen however reduced airflow and increased temperatures in the HT and led to an outbreak of spider mites on raspberries.
Mites: Two spotted spider mite on HT raspberries is an important pest to overcome in organic HT raspberry production in the mid-south. Each year this mite began to build up on lower leaves in early-June and by mid-July or early-August caused most leaves to bronze and die. In July 2014, predatory mite, Neoseiulus californicus was purchased and released into the high tunnel too late in the season and did not provide control of two spotted spider mites. Broad mites on primocane blackberries, particularly the primocane fruiting blackberries, caused leaf cupping and bronzing on primocane terminals from early-June on and can dramatically reduce plant health and yield.
Other arthropods in the high tunnel include: stink bugs were damaged ripening fruit in 2014 and 2015 because insect screen was not installed until June; there were fewer stink bugs in 2016 because insect screen was in place all spring and summer; several species of grasshoppers and katydids had laid eggs in the soil during years without insect screen and caused significant defoliating from mid-July, 2015 and 2016.
In study 2: the traditional floricane blackberries in HT, aphids and sooty mold typically built up more on ‘Natchez’ plants in HT compared to FD plants. In late March and early April 2014, predator lady beetles Coleomegilla maculata 60 and 30 adults and 55 and 30 egg masses, respectively were released into HT and TNT plots to reduce aphid numbers. Subsequent aphid counts indicated some impact of released predators with a reduction in aphids/terminal. In April, 10.5 C. maculata per plant were found in the HT and TNT, respectively, followed by release of 200 and 400 C. maculata beetles in TNT and HT alone, respectively. On 24 April, 400 C. maculata were released in the whole HT. In May, a strong blast of water was applied to the ‘Natchez’ canopy that knocked off remaining aphids and washed off sooty mold from aphid honeydew. A 1% JMS Stylet Oil applied in June 2014, reduced aphid counts per leaf sample from 11.4 aphids/leaf to 4.9 to 1.7 aphids/leaf at 0, 2 and 10 days after treatment (DAT), respectively. In 2015, floricane-fruiting ‘Natchez’ in unscreened HT had ripe fruit all during June but did not have any SWD-infested fruit until 29 June when 100% of berries were infested.
Object 3. To estimate economic models and to create decision support tools that help producers to manage production systems for profitability considerations
The interactive economic decision support tools automatically calculate an estimated enterprise budget derived from values entered by the user and default values derived from research conducted at the AAREC in Fayetteville, AR. After entering the required information and running the model, these tools estimate a budget. There are several options for viewing the results. The results show a breakdown of the expected total costs and returns for the berry enterprise over the entire life of production.
Totals for each year are presented as present values for each cost and return category. A budget summary offers a breakdown of the total annual yield as well as estimated annual total costs and returns. Cumulative net returns are presented in terms of net present values. The user can perform three different types of economic analyses: breakeven, sensitivity and risk. In addition, these interactive economic decision support tools provide economic analyses regarding: 1) the operation’s breakeven (price and yield) points, 2) sensitivity analyses or ‘‘what if’’ scenarios related to changes in costs and returns, and 3) risk assessment by calculating the probability of obtaining a positive net present value over the life of the berry crop. These economic tools are discussed in the economic analysis section.
In summary, three interactive sustainable berry budget tools were developed (blackberry, blueberry, and raspberry). These tools can help estimate costs and returns for field and high tunnel production. Berry producers can create complete production budgets. Additionally, berry producers can perform breakeven, sensitivity and risk analyses to make better production and marketing decisions.
Educational & Outreach Activities
Rodríguez, H.G., J. Popp, C, Rom, and H. Friedrich. 2012. Raspberry Interactive Budget: A Tool for Development of Sound Business Plans. Southern Sustainable Agricultural Working Group. 21st Meeting. Little Rock, AR. January 18-21.
Rodríguez, H.G., J. Popp, C. Rom, and H. Friedrich. 2012. Economic considerations of producing the primocane-fruiting blackberry cultivar Prime-Jan® in Northwest Arkansas. Southern Sustainable Agricultural Working Group. 21st Meeting. Little Rock, AR. January 18-21.
Rodríguez, H.G., J. Popp, C, Rom, and H. Friedrich. 2012. Raspberry Interactive Budget: a tool for development of sound business plans. Southern Sustainable Agricultural Working Group. 21st Meeting. Little Rock, AR. January 18-21.
Rodríguez, H.G., J. Popp, C. Rom, and H. Friedrich. 2012. Economic considerations of producing the primocane-fruiting blackberry cultivar Prime-Jan® in Northwest Arkansas. Southern Sustainable Agricultural Working Group. 21st Meeting. Little Rock, AR. January 18-21.
Rodriguez, H.G., J. Popp, C. Rom, H. Friedrich and L. Freeman. 2014. A software tool for estimating the economic viability of high tunnels in blackberry production. Selected Poster at the Southern Sustainable Agriculture Working Group Annual Meeting, January 16-18, Mobile, AL.
Rom, C.R., M.E. Garcia, D.Johnson, J.Popp, H.Friedrich, J.McAfee. 2012. Potential for Organic High Tunnel Blackberry and Raspberry Production for Season Extension. Southern Sustainable Agricultural Working Group. 21st Meeting. Little Rock, AR. January 18-21.
Rom, C., L.Freeman, J. McAfee, H.Friedrich, S.Fiser, J.Stover, D.Johnson, J.Popp and M.E. Garcia. 2015. Performance of Berries in Field and High Tunnel Production System. 2015 Oklahoma-Arkansas Horticulture Industry Show, Ft. Smith, AR.
Rom. C., 2015. Fruit Production in Tunnels, 2015 Oklahoma-Arkansas Horticulture Industry Show, Ft. Smith, AR.
Freeman, L. Basics of High Tunnel Caneberry Production. 2015 Oklahoma-Arkansas Horticulture Industry Show, Ft. Smith, AR.
Popp, J., H.G. Rodriguez, C. Rom, E. Garcia, H. Friedrich, J. McAfee, and L. Freeman. 2015. Use of apple, blackberry, raspberry and strawberry interactive fruit production budgets. Selected presentation at the Horticulture Industry Show. Fort Smith, AR. January 17.
Rom, C.R. J. McAfee, H. Friedrich, M. E. Garcia, D.T. Johnson. 2013. Research on fruit production in high tunnels. Hort. Industries Show. Fort Smith, AR. (CD-Rom, digital publication)
Popp, J. and H.G. Rodriguez. 2014. Fruit Production: Using Interactive Budgeting Tools to Assess Costs, Revenues and Risks. Selected Presentation. Missouri Organics Association Annual Conference. Feb 6-8, Springfield MO
Johnson, D. 2014. Management of the Spotted Wing Drosophila & Other Insects of Fruit & Berries Selected presentation at the Missouri Organics Association. Springfield MO. February 2014
Johnson, D. 2015. Spotted wing drosophila in blackberries in field and screened high tunnel. Selected presentation at the Missouri Organics Association. Springfield MO. February 5 2015 (part of a High Tunnel Production workshop conducted by our program)
Rom, C. Fruit Production in Tunnels. 2015 presentation Missouri Organic Association. Springfield, MO. February, 2015 (part of a High Tunnel Production workshop conducted by our program)
Garcia, M.E. 2014. High Tunnel Vs. Field Raspberry & Blackberry Production. Selected presentation at the Missouri Organics Association. Springfield MO. February 201
Popp. J., H.G. Rodriguez, C. Rom, E. Garcia, H. Friedrich, J. McAfee, and L. Freeman. 2015. Tools to assess economic returns to high tunnel and in-field small fruit production. Selected presentation at the Missouri Organics Association. Springfield MO. February 5. (part of a High Tunnel Production workshop conducted by our program)
North American Raspberry and Blackberry Association (NARBA)
Soares, R., J. Popp, H.G. Rodriguez, C. Rom, E. Garcia, H. Friedrich, J. McAfee, and L. Freeman. 2015. Follow the Money: new interactive raspberry and blackberry budgets. Selected Presentation North American Raspberry & Blackberry Conference, Fayetteville, AR Feb 24-27, 2015
Rom, C.R., J. McAfee, L. Freeman, H. Friedrich, D.T. Johnson, and M.E. Garcia. 2015. Extending the Market Season with High Tunnel Technology for Organic Blackberry and Raspberry Production. Poster Presentation North American Raspberry & Blackberry Conference, Fayetteville, AR Feb 24-27, 2015.
Rom, C.R., J.McAfee, L. Freeman, H. Friedrich, D.T. Johnson, and M.E. Garcia. 2015. Learning lessons about berry production in high tunnel environments. North American Raspberry & Blackberry Conference, Fayetteville, AR Feb 24-27, 2015.
Rom, C.R. and J. McAfee. 2015. Field tour, presentation, discussion of high tunnel berry production. North American Raspberry & Blackberry Conference, Fayetteville, AR Feb 24-27, 2015.
Caillouet, O., C. Rom, J. McAfee, L. Freeman, and H. Friedrich. 2015. S-SARE Young Scholar Internship: Extending the Market Season with High Tunnel Technology for Organic Fruit Production; an Internship and Apprenticeship for Sustainable Agriculture. Poster Presentation North American Raspberry & Blackberry Conference, Fayetteville, AR Feb 24-27, 2015
Dickey, D.A. and J.D. McAfee. High tunnel selection and construction considerations. Feb 2013 workshop, University of Arkansas, Clarksville AR
Johnson, D. IPM in High Tunnels. June 2013 workshop, University of Arkansas, Fayetteville AR
Rom, C.R. and M.E. Garica. Fruit Production in High Tunnels June 2013 workshop, University of Arkansas, Fayetteville AR
Johnson, D. and B. Lewis. What did we learn this year about spotted wing drosophila? May 2015 workshop, University of Arkansas, Fayetteville AR
Johnson, D. Organic Pest Management for High Tunnel Fruit Production of Small Fruits. May 2015 workshop, University of Arkansas, Fayetteville AR
McAfee, J., L. Freeman, H. Friedrich, S.Fiser, J.Stover, D.Johnson, B.Lewis, J.Popp and M.E. Garcia. Modifying High Tunnels for Improved Performance. May 2015 workshop, University of Arkansas, Fayetteville AR
Rom, C. The Berry Sustainability Workbook. Select presentation, High Tunnel workshop, University of Arkansas, Fayetteville AR, May 24, 2015
Popp, J., H.G. Rodriguez, R. Soares, C. Rom, E. Garcia, H. Friedrich, J. McAfee, D. Dickey and L. Freeman. 2015. Use of interactive budgets in fruit production. Invited presentation at the Small Fruits High Tunnel Production Workshop. Fayetteville AR. May 27
Ginsberg, K., C. Rom, L.Freeman, J. McAfee, and H.Friedrich. 2013. SARE Young Scholar Internship: Extending the market Season with High Tunnel Technology for Organic Fruit Prouction; an Internship and Apprentice for Sustainable Horticulture. SSARE, Griffen GA
Caillouet, O., C. Rom, J. McAfee, L. Freeman, and H. Friedrich. 2014. S-SARE Young Scholar Internship: Extending the Market Season with High Tunnel Technology for Organic Fruit Production; an Internship and Apprenticeship for Sustainable Agriculture. SSARE, Griffen GA
Buck, K., Rom, L.Freeman, J. McAfee, and H.Friedrich. 2015. SARE Young Scholar Internship: Extending the market Season with High Tunnel Technology for Organic Fruit Production
Professional Society Conferences and Scientific publications
Rom, C.R., J. McAfee, L. Freeman, and H. Friedrich. 2014. Observations of frost protection in high tunnels for season extension of berry production. HortScience 49(9):S39
Freeman, L., McAfee, J., and Rom, C. 2016. A Comparison of Blueberry Cultivars in High Tunnel and Field Production. Southern Region American Society of Horticultural Sciences annual conference, Feb 5-7, 2016 San Antonio Tx.
Johnson, D., E. Garcia, C. Rom, L. Freeman, SH. Kim, and B. Lewis. 2016. Management of arthropods on blackberries and raspberries in Arkansas USA Acta Hortic. 1133: 437-444 DOI: 10.17660/ActaHortic.2016.1133.67 http://dx.doi.org/10.17660/ActaHortic.2016.1133.67
Kim S, Trammel C, Lewis B, Johnson D. 2016. Comparison of color attractiveness for Agrilus ruficollis (Coleoptera: Buprestidae): potential for a simple trap. J. Econ. Entomol. Advance Access published June 26, 2016, 1–8 doi: 10.1093/jee/tow142.
Freeman, L.R., C.R. Rom, and J.McAfee. 2016. Tunnel-in-tunnel effects on ‘Natchez’ Blackberry: Promise and Problems. Southern Region American Society of Horticultural Sciences annual conference, Feb 5-7, 2016 San Antonio Tx.
Rodriguez, H.G., J. Popp, C. Rom. L. English, H. Friedrich, C. Lewis and L. Freeman. 2016. Interactive sustainable budget: a tool for developing sound raspberry business plans. Southern Region American Society for Horticultural Science Annual Meeting, San Antonio, TX. February 5-7.
Popp, J., H.G. Rodriguez, C. Rom. L. English, H. Friedrich, C. Lewis and L. Freeman. 2016. Assessing financial risks to blackberry production with an interactive decision support tool. Southern Region American Society for Horticultural Science Annual Meeting, San Antonio, TX. February 5-7.
Rodriguez, H.G., J. Popp, C.R. Rom, H. Friedrich, and L. Freeman. 2015. Estimating the economic feasibility of producing blackberries for four different production systems. American Society of Horticultural Sciences. Aug. 4-7, New Orleans, LA.
Rodriguez, H.G., J. Popp, H. Friedrich and L. Freeman. 2015. Estimating the economic feasibility of producing blackberries for four different production systems. HortScience 50(9): S289-290.
Sok, S. J. Popp and H.G. Rodriguez. 2014. Facilitating highbush blueberry production management by employing a user friendly interactive decision support tool. Journal of Agricultural and Applied Economics. Abstract 46(2014):393.
Sok, S., J. Popp, and H.G. Rodriguez. 2014. Facilitating highbush blueberry production management by employing a user friendly interactive decision support tool. Selected Poster for the Southern Agricultural Economics Association Annual Meeting, Feb. 1-4, Dallas, TX.
Sok, S., J. Popp, H.G. Rodriguez, and E. Garcia. 2014. Assessing risks and returns from blueberry production using a decision support tool. Selected Presentation at the Western Agricultural Economics Association Annual Meeting. Jun4-7, Colorado Springs, CO.
Rodriguez, H.G., J. Popp, C. Rom, H. Friedrich and L. Freeman. 2014. Berry Production: using interactive budgeting tools to assess costs, revenues and risks. Selected Poster at the American Society of Horticultural Sciences Annual Meeting. July 28-31, Orlando, Fl.
Rodríguez, H.G. Popp, J. Thomsen, M.R., Friedrich, H. and Rom, C.R. 2012. Economic analysis of investing in open-field or high tunnel primocane-fruiting blackberry production in northwestern Arkansas. HortTechnology. 22(2):245-251.
Fiser, S.K., C.R. Rom, J.D. McAfee, L.R. Freeman, E. Gbur. 2015. Effects of water stress on physiology and growth of potted primocane-fruiting blackberries in a controlled environment. HortScience 50(9):S383
- Rom, L. Freeman, H. Friedrich, E. Garcia, D. Johnson, and J. Popp. 2015. Sustainable blackberries & raspberries a self-assessment workbook for growers. University of Arkansas and Center for Agricultural and Rural Sustainability, 76 pages (pdf).
Kim, S-H. 2014. Control of Agrilus ruficollis (coleoptera: buprestidae) with insecticides and identifying visual attractants of use in a monitoring trap. Ph.D. dissertation, University of Arkansas, Fayetteville, 76 pp.
Rodriguez, H.G., J. Popp, C. Rom, L. English, H. Friedrich, L. Freeman, C. Lewis, and R. Soares. 2016. Interactive Sustainable Blackberry Budget. University of Arkansas System, Division of Agriculture Center for Agricultural and Rural Sustainability, Fayetteville, AR.
Rodriguez, H.G., J. Popp, S. Sok, L. English, C. Lewis, and E. Garcia. 2016. Interactive Sustainable Blueberry Budget. University of Arkansas System, Division of Agriculture Center for Agricultural and Rural Sustainability, Fayetteville, AR.
Rodriguez, H.G., J. Popp, C. Rom, L. English, H. Friedrich, L. Freeman, and C. Lewis. 2016. Interactive Sustainable Raspberry Budget. University of Arkansas System, Division of Agriculture Center for Agricultural and Rural Sustainability, Fayetteville, AR.
Sok, S. J. Popp and H.G Rodriguez. 2014. Facilitating high-bush blueberry production management by employing a user friendly interactive decision support tool. Selected Poster at the Annual Gamma Sigma Delta Conference, March 12, Fayetteville, AR.
Caillouet, O.C. C. R. Rom, J. McAfee, L. Freeman, and H. Friedrich. 2016a. Effect of timing of shade on growth, development, physiology, and fruiting of a primocane fruiting blackberry in a controlled environment. Discovery, The Undergraduate Research Journal of the Bumpers College of Agricultural, Food and Life Sciences. 17: 17-24
Caillouet, O.C. C. R. Rom, J. McAfee, L. Freeman, and H. Friedrich. 2016b. The effects of shade on primocane fruiting blackberries in the field. Discovery, The Undergraduate Research Journal of the Bumpers College of Agricultural, Food and Life Sciences. 17: 25-32
Results of the high tunnels studies in this project continue to provide evidence that HT production of blackberries can produce larger yields, higher quality berries, advance production for floricanes (2+ weeks) and extended production for primocanes (2-5 weeks), compared to field production, making HT an ideal complimentary system to field production. HT raspberry production in the mid-South could potentially be successful with sufficient prevention of two-spotted mite buildup and extra measures to ensure that flooding does not occur to create conditions for soil diseases. TNTs were useful in both increasing HT temperatures during cold periods, and retaining night time temperatures however bumble bee activity may be reduced under TNT and requires additional investigation.
Tunnels provide additional opportunities for environmental modification to control plant growth, cropping, and pest management. Shading was studies as a means of delaying flowering in primocane blackberries as a method of summer heat avoidance. Field studies provided proof of concept that shading can delay flowering, but the studies also demonstrated reductions in yields. However, a preliminary greenhouse study provided evidence that shading earlier in the growing cycle may delay flower and increase yield. However, this concept has not been fully tested nor replicated under field conditions. Shading did improve yield and fruit quality of primocane raspberries significantly. Raspberries are a more shade tolerant crop than blackberries and shade may be needed to optimize HT performance of primocane raspberries in warm, sunny southern environments.
Overhead micro-irrigation and misting demonstrated the potential for evaporative cooling of tunnels. Our studies again, demonstrated a proof of concept, but did not fully develop the technology and additional research is needed.
The tunnel modifications of TNT, shading, and overhead misting/evaporative cooling provide additional opportunities to broaden the harvest season, improve environmental control with low-scale technologies, and further enhance the HT production system for berries.
Different insect pest management practices are required for HT compared to FD production due to the change within HT environment. HT conditions are more favorable to mites and aphid outbreaks. Screening can be an effective method to prevent SWD infestation along with other larger flying insects. This is especially relevant for organic berry production where the efficacy of materials available to control SWD are limited. Although the screen was a highly effective pest management tool, it contributed to an excessive heat problem which could have detrimental effects on the crop and fruit. The installation of a micro-mist/fogger system could be used to lower temperatures through evaporative cooling.
As a result of these studies a better understanding of bio-pesticide and biological control options for high tunnel has been initiated and needs and opportunities for further research have been identified. Co-PI Johnson is involved with a national organic SWD (USDA-OREI funded) project. A more attractive bait/spinosad combination needs to be developed to eliminate the aphid-tending odorous house ants from the screened HT so aphids can be controlled by mass release of predator beetles and parasitoids. The efficacy of mass releasing the predator beetle, Scymnus creperus, for biological control of aphids in HT will continue to be evaluated. Efficacy studies are in progress for applications of various biopesticides, e.g., Microthiol, JMS Stylet Oil and M-Pede, against broad mite and mass releases of predatory mites, Amblyseius andersoni, N. cucumeris, N. swirskii, or N. californicus, for biological control of broad mites.
The efficacy of mass trapping of brown and green stink bugs with yellow traps baited with specific kairomone and aggregation pheromone will be evaluated. For grasshoppers inside HT, the effect of tilling on emergence of young grasshoppers in HT and amount of suppression achieved by applying Semaspore Bait (the Nosema locustae protozoa attached to wheat bran) to the hatching beds - grassy areas will be evaluated. The use of green funnel traps to detect rednecked cane borer male flight to improve timing of several weekly foliar applications of JMS Stylet Oil against redneck cane borer will be validated in 2017.
Because of the interactive tools developed in this project, berry producers can assess potential costs and returns of different types of operations (field or high tunnel production) under different production and marketing assumptions without undertaking the financial risk first. The tools are available for free at (http://cars.uark.edu/ourwork/Specialty-Crop-Production-and-Marketing/fruit_budget.aspx). Although, the default data make the tools particularly relevant to producers in the southern U.S, with real farm economic data, they can be applicable to any berry crop in the U.S. These interactive economic tools will help existing and new berry producers to evaluate total production costs, production and marketing risks, determine potential returns, perform economic analyses, prepare budgets and compare different scenarios.
These studies and facilities provided a living-learning laboratory that were used by undergraduate apprentices, interns, by graduate students within our program and collaborating programs, employees, and for classroom experiential learning. These facilities, as an indirect output and impact of this grant project, enhanced the experience, education, and learning of many students.
As a result of the multi-dimensional outreach activities, growers, extension agents and scientists learned about this project and interest in high tunnel fruit production has expanded. Production, season extension, pest management, sustainability and economic information from this study was presented at local, regional, and national grower workshops/conferences, and at national scientific and extension meetings. Information and experiences gained in these studies contributed to the development of a Sustainable Blackberry and Raspberry Self-Assessment Workbook for growers, found at http://cars.uark.edu/ourwork/BlackberryWorkbook2016-2nd_final.pdf. Growers now have this resource along with the interactive budgets to help guide their decision-making process on their farm to improve their overall farm sustainability. The workbook, although available on-line, has had two hard-copy publication runs that were both completely distributed and put into use by growers.
Three different types of economic analyses can be performed using the interactive budget tool which can help growers make decisions regarding their berry production. The results are presented in terms of net present values. The user can perform breakeven, sensitivity and risk analyses.
The breakeven analysis option allows the user to determine the selling price and fruit yield that will result in the berry operation breaking-even (net profit equal to zero) at the end of the full production period. It also uses price and yield information entered by the user to estimate the crop breakeven year. This is the year the producer can expect to begin seeing net profits from the berry operation. The breakeven analysis will display a graphical representation of the operation totals and breakeven values (yields and prices). The point where the berry operation cumulative total returns equal the cumulative total costs is the breakeven point. These tools will list the prices and yields that each type of fruit (fresh vs. processed) must achieve in order to cover total production costs. A new scenario can be compared to the original information entered by the user. The breakeven analysis option provides a financial snapshot based on the information entered by the user. To see what would happen if these values were to change; the user can perform a sensitivity analysis.
This analysis technique is helpful to determine how changes in input values such as yield or price could impact the overall return of the berry crop. It is a great tool that allows the user to make better decisions by predicting the outcome of different scenarios. The user can perform these analyses as many times as they like without having to modify the initial input. These tools allow comparing two set of graphs at the same time. The first set of graphs offers results for the initial input scenario. The graph is generated using values initially entered by the user. The second set of graphs shows the results for the comparison scenario. Comparing between different scenarios helps to predict the outcome of a decision if a situation turns out to be different from the current situation. The user might like to know how the cumulative total costs, gross returns, and net returns will be affected if a change occurs (for example, unexpected lower yields, lower prices, etc.). This “What If” analysis presents instantly the impact of a change in one or more of the inputs on the economic feasibility of the whole berry crop.
The budgets also include a risk analysis component. In these tools, risk analysis is defined as a technique that calculates the probability of obtaining a cumulative net return greater than a specific dollar target. This target is set by the user. The user needs to enter a “minimum”, “most likely” and “maximum” values for yield (lb/plant) and prices ($/lb) as well as the percentage of usage for each fruit quality each year. Additionally, the user can enter a constant percentage by which the total cost might increase or decrease each year. After all the input information is recorded, the model will calculate the probability of the net return value being equal or greater than the specific dollar target chosen. To accomplish this task, the model uses a triangular distribution to generate hundreds of different present values of net returns, given some expectations about costs, yields, percentages of yield sold to different markets, as well as prices received from those markets. It also generates the range where the average present value of net return will lie. The initial scenario can be compared to a new scenario by running a second analysis using different values.
It is difficult to accurately estimate farmer adoption of high tunnel production of brambles however, through this project grower have increased knowledge of sustainable and organic high tunnel production of blackberries and raspberries, modifications to high tunnels to further modify the environment and and increased knowledge of insect pest management. We have witnessed and increased interest in production of blackberries and primocane fruiting raspberries and blackberries in the region and an increased interest in using high tunnels for fruit production. The Sustainable Production and Assessment Workbook is providing production guidance to growers for beginning/novice and intermediate producers. A greater number of growers have the knowledge and ability to use the sustainability self-assessment to track and improve their farm sustainability. A greater number of growers have the knowledge and ability to use the interactive enterprise budgets to make informed fruit management decisions.
Areas needing additional study
Various areas were mentioned above that need additional investigation. Some of these include:
- Optimization of timing and amount of shade for managing time of primocane blackberry flowering in hot environments.
- Optimizing the level of shade for raspberry production.
- Optimizing overhead misting for screened HT temperature management
- Optimizing air circulation within screened tunnels.
- Optimizing Bumble bee pollinator activity, especially under TNT and Shade structures within the HT
- Biocontrol for insect pest management in HT especially mites and aphids
- Organic pesticide use for optimal pest management.
- Life-cycle sequence of emerging insect pests within the HT
- Water use in HT environments compared to FD environments