Progress 08/15/08 to 08/14/11
Outputs
OUTPUTS: We established a 0.4 ha planting in Oct. 2006 to evaluate the effects of cultivar (Duke; Liberty), bed type (flat; raised), weed management (sawdust mulch and hand-weeding; compost topped with sawdust with acetic acid, lemongrass oil and hand weeding; weed mat), and fertilizer (feather meal and fish emulsion at 29 and 57 kg of N/ha (2007-2009) and 57 and 102 kg/ha (2010-11). The site was certified organic in 2008. Research: 1. Evaluate organic weed management, fertility, and production systems. Weeds never exceeded 20-25% coverage in 2007-2010; weed mat resulted in the fewest weeds and compost plus sawdust had the most. Acetic acid or lemongrass oil applied every 3 wks in summer was effective on small weeds. Hand-weeding was required in all treatments. Plants grown on raised beds were larger and had 48% greater cumulative yield than those on flat ground (years 1-4). Raised beds with weed mat required double the irrigation volume than flat plantings in years 1-3, but not in year 4. In 2010, yield averaged 1.8 kg/plant. Fertilization with the low rate of fish emulsion or the high rate of feather meal resulted in high yields in 2009 and 2010. Yield was higher with weed mat or sawdust plus compost than with only sawdust. Weed mat reduced fruit firmness compared to organic mulches in all years except 2010. Plant-available N was greater under weed mat than sawdust but availability of Ca and K was lower. Soil pH was lowest under weed mat and highest under sawdust plus compost. 2. Develop a compost for blueberry. Compost feedstocks evaluated included animal manure solids + bedding (horse or dairy), urban yard debris, and farm by-products (grass seed screenings, spent hops, or peppermint distillation residue). Elemental S required to acidify compost to below pH 6 ranged from 3 to 12 kg S per metric ton dry compost. Plants grew better in plant-derived composts than in manure-derived composts, and compost acidification increased growth. Compost pH limited growth more than soluble salts. Composts for blueberry typically have a low to medium pH buffering capacity, requiring addition of 3 to 6 kg S per metric ton dry compost to reduce pH to less than 5.5. Extension: 1. Develop economic enterprise budgets. Inputs were documented and organic fruit sold throughout the project to document costs/returns. An extension cost of establishment publication was developed with information shared with peers at conferences. 2. Produce workshops, field days, publications and web-based tools. We have given the following presentations, 2008-11: field days for growers (17); grower meetings (6); webinars (3); scientific meetings (7); and international invited (4). 3. eOrganic. We used eOrganic to enhance project outreach. Three webinars were conducted describing the ongoing project and providing research-based information to clientele. The webinar outreach included participation from all 3 project PIs, 1 graduate research assistant and 1 postdoctoral research associate (webinars reached more than 158 listeners from 32 states and 2 countries). Peer-reviewed, online materials (pages in eOrganic) were developed describing the project. PARTICIPANTS: Participants: Bernadine C. Strik, Professor of Horticulture, Oregon State University David Bryla, Research Horticulturist, USDA-ARS, HCRL, Corvallis Dan Sullivan, Assoc. Professor of Crop and Soil Science, Oregon State University Clark Seavert, Professor, NWREC, Oregon State University, Aurora Gil Buller, Senior Research Assistant, NWREC, Oregon State University Handell Larco, M.S. graduate student, Dept. Horticulture, OSU Ryan Costello, M.S. graduate student, Dept. Crop and Soil Sci, OSU Luis Valenzuela, post-doctoral associate, USDA-ARS, HCRL and Dept. Hort., OSU James Julian, Research Assistant, NWREC, OSU, Wei Yang, Assoc. Professor, NWREC, OSU Nick Andrews, Small Farms Agent, NWREC, OSU Eric Pond, Riverbend Farms, Jefferson, Ore. Adam Wagner, Fall Creek Farm and Nursery, Lowell, Ore. Steve Erickson, Pan-American Berry Growers, Salem, Ore. Chrislyn Particka, Sakuma Bros. research, Wash. Joe Bennett, Small Planet Foods, Wash. Partner organizations: Oregon Blueberry Commission Washington Blueberry Commission Northwest Center for Small Fruits Research USDA-ARS, HCRL, Corvallis Growers in Oregon and Washington TARGET AUDIENCES: Commercial berry crop growers Organic growers Crop consultants Academic peers PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The following questions were listed as research outcome goals: 1. What is the most effective way to control weeds Weed mat has been the most effective mulch for weed control. Propane flaming and acetic acid have been effective contact weed control methods provided weeds are small and environmental conditions are favorable. Lemongrass oil was an effective contact herbicide against small weeds in 2010-11. 2. Can we use weed mat to substitute for sawdust mulch (industry standard practice) for weed control Weed mat is effective for weed control, but the impact of higher soil temperature on plant growth needs more assessment. Root production was lower under weed mat than under organic mulches, and raised beds with weed mat required more irrigation than flat beds or beds covered with sawdust. 3. What fertility inputs can be used to supply the crop with adequate N Fish emulsion was equal or superior to feather meal for plant growth and was most effectively applied by fertigation. Soil N availability was relatively consistent with fish but higher under weed mat than under sawdust mulch. Higher N availability under weed mat was associated with higher soil temperatures and thus a more rapid conversion of organic N (fish and organic matter) to ammonium- and nitrate-N. The use of fish resulted in stable or a slight decrease in soil pH over the course of the study while soil EC remained very low and therefore had little to no impact on plant growth. The lower rate of fish fertilizer has resulted in the highest yields. 4. Can compost be used as a fertility source in organic production Plant-derived composts show promise to enhance organic blueberry production. Compost pH, not salt content, has been the major obstacle to compost use for blueberry. Our research shows that compost can be acidified via elemental S addition, and that plants grow better in acidified compost. We have developed and verified a quick test to determine how much S needs to be added to acidify compost to pH 5 to 5.5 (ideal for blueberry). 5. Do blueberries need to be grown on raised beds Growth and production were greater in plants grown on raised beds than in those grown on flat ground. Raised beds reduced soil water holding capacity but increased root growth and rooting depth to enable plants to acquire more water and nutrients. 6. What impact will altered production practices have on long-term plant health and sustainability Plant rooting differed among production practices. The low rate of fish fertilizer, for example, produced deeper and 30% more roots than the higher rate of fish fertilizer, while plants on raised beds produced deeper and 45% more roots than on flat ground. Plants with sawdust mulch produced more roots than with weed mat. Such practices increase the ability of blueberry to acquire water and nutrients and therefore reduce the need for irrigation and fertilizers. 7. Can blueberries be grown economically using the recommended sustainable organic production systems Cumulative net production costs (years 0-3) varied as much as 65% among treatments, ranging from -$32,690/ha to -$54,050/ha (net loss), similar to costs expected for conventional production.
Publications
- Strik, B.C., D. Bryla, H. Larco, and J. Julian. 2011. Organic Highbush Blueberry Production Systems Research - Management of Plant Nutrition, Irrigation Requirements, Weeds, and Economic Sustainability. Intern. Hort. Congress, Lisbon, Portugal. Acta Hort. (in press)
- Julian, J., B. Strik, E. Pond., and W. Yang. 2011. Blueberry economics: The Costs of Establishing and Producing Organic Blueberries in the Willamette Valley, Oregon. AEB 0023, July
- Valenzuela-Estrada, L.R., D.R. Bryla, D.M. Sullivan, and B.C. Strik. 2011. Influence of weed mat and surface sawdust mulch on soil nutrient availability and soil chemical properties under organic blueberry production. 2011 ASHS Annual Conference, Hilo, Hawaii, 25-28 September 2011 (abstract).
- Costello, Ryan C., Shannon B. Andrews and Dan M. Sullivan. 2011. Laboratory titration to predict S required for compost acidification. SSSA Annual Meeting. San Antonio, TX. 16-20 Oct. 2011. http://a-c-s.confex.com/crops/2011am/webprogram/Paper66759.html
- Costello, R.C., D.M. Sullivan, D.R. Bryla, B.C. Strik and J. Owen. Highbush blueberry response to compost and sulfur. p. 67-72. In: Proc. Western Nutrient Mgmt. Conf. 3-4 Mar 2011. Reno, NV. Online at: https://sites.google.com/site/westernregion103/committee-output/confe rence-proceedings-2011
- Strik, B.C., D. Bryla, and D. Sullivan. 2010. Organic Blueberry Production Research Project. Available at: http://www.extension.org/article/31680
- Valenzuela, L., D. Bryla, D. Sullivan, and B.C. Strik. 2011. Organic Blueberry Production Research Project: Roots. Available at: http://www.extension.org/article/32763
- Strik, B., Vollmer, E., Buller, G., Bryla, D. and Sullivan, D. 2011. Organic blueberry production reseach project. Oregon Blueberry Update, spring, 2011
- Costello, R. and D. Sullivan. 2010. Development of Custom Compost for Highbush Blueberry. Soil Science Soc. Am. annual meeting, Long Beach, CA. Available at: http://a-c-s.confex.com/crops/2010am/webprogram/Paper60079.html
- Larco, Handell O. 2010. Effect of planting method, weed management, and fertilizer on plant growth and yield of newly established organic highbush blueberries. M.S. thesis. Oregon State University. http://hdl.handle.net/1957/18065
- Sullivan, Dan M. and Ryan Costello. 2010. Breaking it down: Growers can get the most value from their compost by having it analyzed first. Digger (Oregon Association of Nurseries). 54 (10): 42-46.
- Valenzuela-Estrada, L., O.L. Vargas, D.R. Bryla, D.M. Sullivan, and B.C. Strik. 2010. Blueberry root dynamics and nutrient management under organic and conventional production. HortScience 45:S34 (Abstr.).
- Strik, B. and D. Bryla. 2010. Weed, water, and nutrient management practices for organic blackberry production. Proc. Northwest Center for Small Fruits Research, Dec., 2010, Boise, ID 19:92-93
- Larco, H., D.M. Sullivan, B. Strik, and D. Bryla. 2011. Mulch effects on highbush blueberry under organic management. p. 53 In: Abstracts, ISHS Intl. Symposium Organic Matter & Compost Use in Horticulture. Apr. 2011. Adelaide, AU. Acta Hort.(in press)
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Progress 08/15/09 to 08/14/10
Outputs
OUTPUTS: Outputs are described under each objective Research: 1. Evaluate organic weed management, fertility, and production systems. Weeds never exceeded 20-25% coverage in 2007-2009; weed mat resulted in the fewest weeds and compost plus sawdust had the most. Flaming in spring and acetic acid applied every 3 wks in summer was effective on small weeds. Hand-weeding was required in all treatments. Plants grown on raised beds were larger and had 63% greater cumulative yield than those on flat ground (years 1-3). Raised beds, particularly with weed mat, required up to 269 L/plant/season more irrigation than flat ground plantings. In 2009, yield averaged 1.7 kg/plant and was highest with 29 kg/ha N of fish or 57 kg/ha of feather meal and lowest with 57 kg/ha of fish. Yield was higher with weed mat or sawdust plus compost than with only sawdust. Weed mat reduced fruit firmness compared to organic mulches. Plant-available N was greater under weed mat than sawdust but availability of Ca and K was lower. Soil pH was lowest under weed mat and highest under sawdust plus compost. 2. Develop a compost for blueberry. Two plant growth trials evaluated compost effects on root and above-ground growth. Composts were added to soil at a high rate (30% v/v). Controls were soil alone and soil + sawdust (industry standard). Trials were done in winter in greenhouse (1-gal pots; Jan-May) and outdoors in summer (5-gal pots; May-Sept). In the greenhouse, plant growth was limited when composts having pH above 7.5 and EC above 4 mS/cm were incorporated into soil. Plant-derived composts performed better than manure-derived. Acidification of composts with elemental S increased plant growth. Compost pH was a greater limiting factor to plant growth than soluble salts. Elemental S addition increased compost EC, but also increased plant growth. When grown at low levels of N addition (winter trial), compost increased plant growth above that observed with sawdust addition. At higher rates of fish fertilizer (summer trial), plant growth with compost was equal to, or less than growth with sawdust. Extension: 1. Develop economic enterprise budgets. Costs have been documented to date. Certified organic fruit were sold in 2009-10 to document returns. Development of an extension cost of establishment publication is in progress. 2. Produce workshops, field days, publications and web-based tools. We have given the following presentations: field days (11); grower meetings (6); scientific meetings (4); and international invited (4). This project was highlighted at the Blueberry Field Day at the NWREC in 2008-10. 3. eOrganic. We used eOrganic to enhance project outreach. Two webinars were conducted describing the ongoing project and providing research-based information to clientele. The webinar outreach included participation from all 3 project PIs, 1 graduate research assistant and 1 postdoctoral research associate (webinars reached more than 158 listeners from 32 states and 2 countries). Online materials (pages in eOrganic) were developed describing the project. These are under review. Video recorded at the OSU Blueberry Field Day (July 2010) is being edited for release via eOrganic. PARTICIPANTS: Participants: Bernadine C. Strik, Professor of Horticulture, Oregon State University David Bryla, Research Horticulturist, USDA-ARS, HCRL, Corvallis Dan Sullivan, Assoc. Professor of Crop and Soil Science, Oregon State University Clark Seavert, Professor, NWREC, Oregon State University, Aurora Gil Buller, Senior Research Assistant, NWREC, Oregon State University Handell Larco, M.S. graduate student, Dept. Horticulture, OSU Ryan Costello, M.S. graduate student, Dept. Crop and Soil Sci, OSU Luis Valenzuela, post-doctoral associate, USDA-ARS, HCRL and Dept. Hort., OSU James Julian, Research Assistant, NWREC, OSU, Wei Yang, Assoc. Professor, NWREC, OSU Nick Andrews, Small Farms Agent, NWREC, OSU Eric Pond, Riverbend Farms, Jefferson, Ore. Adam Wagner, Fall Creek Farm and Nursery, Lowell, Ore. Steve Erickson, Pan-American Berry Growers, Salem, Ore. Chrislyn Particka, Sakuma Bros. research, Wash. Joe Bennett, Small Planet Foods, Wash. Partner organizations: Oregon Blueberry Commission Washington Blueberry Commission Northwest Center for Small Fruits Research USDA-ARS, HCRL, Corvallis Growers in Oregon and Washington TARGET AUDIENCES: Target audiences: Commercial berry crop growers, Organic growers, Crop consultants, Academic peers PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The following questions were listed as research outcome goals: 1. What is the most effective way to control weeds Weed mat has been the most effective mulch for weed control. Propane flaming and acetic acid have been effective contact weed control methods provided weeds are small and environmental conditions are favorable. 2. Can we use weed mat to substitute for sawdust mulch (industry standard practice) for weed control Weed mat is effective for weed control, but the impact of higher soil temperature on plant growth needs more assessment. Root DW was lower under weed mat than under organic mulches and raised beds with weed mat required extra irrigation in year 2. 3. What fertility inputs can be used to supply the crop with adequate N Fish emulsion was equal or superior to feather meal for plant growth. Inorganic N availability was relatively consistent with fish over a 14-wk period (late Apr thru July) for weed mat and sawdust mulches. Soil N, nitrate, and ammonium were higher with weed mat than with sawdust and higher near the soil surface in flat than in raised beds. Soil pH was higher with sawdust than with weed mat and lower as more N fertilizer was applied, while EC increased as more N was applied but only on raised beds; pH and EC were within the range considered "safe" for blueberry. 4. Can compost be used as a fertility source in organic production Plant-derived composts show promise to enhance organic blueberry production. Compost pH, not salt content, has been the major obstacle to compost use for blueberry. Our research shows that compost can be acidified via elemental S addition, and that plants grow better in acidified compost. We have developed and verified a quick test to determine how much S needs to be added to acidify compost to pH 5 to 5.5 (ideal for blueberry). 5. Do blueberries need to be grown on raised beds After the second growing season, total plant DW was greater in raised beds than on flat. Soil water content was lower in raised beds than in flat ground with sawdust but was higher in raised beds than in flat ground with weed mat. Soil N was lower at 15 cm than at 35 cm in raised beds, but more roots were located at the 35 cm depth. 6. What impact will altered production practices have on long-term plant health and sustainability Root production was monitored starting in 2009 using 90 minirhizotron tubes. More than 8,000 digital images were captured bi-weekly throughout the last two growing seasons. So far, most roots were produced shortly after harvest, implying root production is C-source limited and will differ depending on pruning and fruit set. In general, the low rate of fish fertilizer produced deeper and 1.3 times as many roots as the high rate of fish fertilizer, while raised beds produced deeper and 45% more roots than flat beds, and sawdust mulch produced more roots than weed mat. 7. Can blueberries be grown economically using the recommended sustainable organic production systems Cumulative net production costs (years 0-3) varied as much as 60% among treatments, ranging from -$32,690/ha to -$51,990/ha (net loss), similar to costs expected for conventional production.
Publications
- Strik, B., D. Bryla, and H. Larco. Organic Blueberry Production Webinar. Presented March, 2010 via eOrganic. Available at: http://www.extension.org/article/26115
- Sullivan, D., L. Valenzuela, and R. Costello. 2010. Undercover Nutrient Investigation: The Effects of Mulch on Nutrients for Blueberry Webinar. Presented Jan, 2010 via eOrganic. Available at: http://www.extension.org/article/25232.
- Costello, R. and D. Sullivan. 2010. Development of Custom Compost for Highbush Blueberry. Soil Science Soc. Am. annual meeting, Long Beach, CA. Available at: http://a-c-s.confex.com/crops/2010am/webprogram/Paper60079.html
- Larco, Handell O. 2010. Effect of planting method, weed management, and fertilizer on plant growth and yield of newly established organic highbush blueberries. M.S. thesis. Oregon State University. http://hdl.handle.net/1957/18065
- Valenzuela-Estrada, L., O.L. Vargas, D.R. Bryla, D.M. Sullivan, and B.C. Strik. 2010. Blueberry root dynamics and nutrient management under organic and conventional production. HortScience 45:S34 (Abstr.).
- Costello, Ryan. Composting and Blueberry Production. p. 15-16. In: Small Farm News. OSU Extension. Fall, 2009.
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Progress 08/15/08 to 08/14/09
Outputs
OUTPUTS: Outputs are described under each objective Research: 1. Evaluate organic weed management, fertility, and production systems. A research assistant maintained weed management and fertility treatments. Data were collected on weed presence, plant growth, and yield. Records on all costs were maintained. We hired and trained a postdoc to monitor root growth and measure availability of soil water and nutrients. In 2008, the sawdust+compost mulch had more weeds than the sawdust or weed mat and required hand pulling of weeds plus one application of 20% acetic acid and 2 propane flaming treatments. Weed mat had the fewest weeds, although hand pulling was required around the plants. Plant-available N was greater under weed mat than sawdust but availability of Mg was lower. The weed mat also had greater availability of P, S, Mn and Zn later in the season (July) compared to sawdust. In Oct. 2008, total plant dry weight (DW) was greater in Liberty, on raised beds, and at a N rate of 29 kg/ha of fish in Duke and 57 kg/ha of fish in Liberty. Root DW was greater with organic mulches fertilized with 29 kg/ha N of fish. Yield in 2008 (second growing season) was greater in Liberty than Duke, on raised beds, and on plants fertilized with fish. Weed mat reduced fruit firmness compared to organic mulches. 2. Develop a compost for blueberry. A graduate student (Costello) began work in Apr. 2009. Ten composts were produced from locally-available organic materials in preparation for blueberry growth trials. Feedstocks for compost production included separated dairy solids, ground yard debris, bean and corn cannery byproducts, spent peppermint hay, horse manure+sawdust bedding, spent hops from a brewery, and grass clippings from urban landscaping. Composting was performed in small produce bins. Compost temperatures during the first 4-6 wks exceeded 50C for most mixtures, simulating realistic composting-process conditions. Most composts met NOP time/temperature standards for human pathogen elimination. We measured compost pH and electrical conductivity (EC) in 1:10 compost:water extracts. After 10-wk of composting, pH and EC for the composts were greater than desired for blueberry (pH< 6.5 and EC<1.5). The most promising composts were made from separated dairy solids and peppermint hay. We conducted 3-d laboratory incubations to determine the quantity of acid required to decrease compost pH to the desired range. For the 5 composts evaluated so far, we estimate that addition of 1-2 kg fine elemental S per m3 would be required to decrease compost pH to below 6. Extension: 1. Develop economic enterprise budgets. Costs have been documented to date. Certified organic fruit were sold in 2009 with documentation of returns. Development of an extension cost of establishment publication is in progress. 2. Produce workshops, field days, publications and web-based tools. We have given the following presentations: field days (4); grower meetings (5); scientific meetings (2); and international invited (3). This project was highlighted at the Blueberry Field Day at the NWREC in 2008 and 2009. 3. eOrganic. We developed an eOrganic community of practice related to this project PARTICIPANTS: Bernadine C. Strik, Professor of Horticulture, Oregon State University David Bryla, Research Horticulturist, USDA-ARS, HCRL, Corvallis Dan Sullivan, Assoc. Professor of Crop and Soil Science, Oregon State University Clark Seavert, Professor, NWREC, Oregon State University, Aurora Gil Buller, Senior Research Assistant, NWREC, Oregon State University Handell Larco, M.S. graduate student, Dept. Horticulture, OSU Ryan Costello, M.S. graduate student, Dept. Crop and Soil Sci, OSU Luis Valenzuela, post-doctoral associate, USDA-ARS, HCRL and Dept. Hort., OSU James Julian, Research Assistant, NWREC, OSU, Wei Yang, Assoc. Professor, NWREC, OSU Nick Andrews, Small Farms Agent, NWREC, OSU Eric Pond, Riverbend Farms, Jefferson, Ore. Adam Wagner, Fall Creek Farm and Nursery, Lowell, Ore. Steve Erickson, Pan-American Berry Growers, Salem, Ore. Chrislyn Particka, Sakuma Bros. research, Wash. Joe Bennett, Small Planet Foods, Wash. Partner organizations: Oregon Blueberry Commission Washington Blueberry Commission Northwest Center for Small Fruits Research USDA-ARS, HCRL, Corvallis Growers in Oregon and Washington TARGET AUDIENCES: Target audiences: Commercial berry crop growers Organic growers Crop consultants Academic peers PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The following questions were listed as research outcome goals: 1. What is the most effective way to control weeds Weed mat has been the most effective mulch for weed control. Propane flaming and acetic acid have been effective contact weed control methods provided weeds are small and environmental conditions are favorable. 2. Can we use weed mat to substitute for sawdust mulch (industry standard practice) for weed control Weed mat is effective for weed control, but the impact of higher soil temperature under weed mat on plant growth needs more assessment. Root DW was lower under weed mat than under organic mulches. Raised beds with weed mat required 300 L/plant of extra irrigation in year 2. 3. What fertility inputs can be used to supply the crop with adequate N Fish emulsion was equal or superior to feather meal for total plant growth. Inorganic N availability was relatively consistent with fish over a 14-wk period (late Apr thru July) for weed mat and sawdust mulches. In general, pH was higher with sawdust than with weed mat and lower as more N fertilizer was applied, while EC increased as more N was applied but only on raised beds; neither pH or EC were unusual for blueberry, and both were within the range considered "safe". 4. Can compost be used as a fertility source in organic production Yard debris compost+sawdust mulch at planting gave 25% more yield, but increased labor cost for controlling weeds by 63% compared to sawdust mulch alone. Produced novel composts from locally-available feedstocks, all of which had pH>6 (require elemental S or other acidifying agent to reduce pH for blueberry). Developed a "quick test" to estimate the amount of acidifying agent needed to overcome high pH. Composted dairy solids and peppermint hay best fit target pH and salt levels for blueberry. 5. Do blueberries need to be grown on raised beds After the second growing season, total plant DW was greater in raised beds than on flat ground. Soil water content was lower in raised beds than in flat ground with sawdust but was higher in raised beds than in flat ground with weed mat. Raised beds required 190 L/plant more irrigation water than flat ground in year 2. 6. What impact will altered production practices have on long-term plant health and sustainability Root production was monitored starting in 2009 using 90 minirhizotron tubes. A total of 3,960 digital images were captured bi-weekly throughout the growing season. So far, we determined that most roots were produced shortly after harvest, implying root production is carbon-source limited and will differ depending on pruning and fruit set. 7. Can blueberries be grown economically using the recommended sustainable organic production systems The total costs of land preparation, planting establishment, and maintenance after year 1 ranged from $30,311 to $35,534/ha depending on treatment. Raised beds increased costs $1,263, on average, compared to planting on flat ground. Adding compost to the mulch increased costs $976 in flat ground and $1,156 in raised beds for materials and labor, but also increased weed management costs by $1,519 due to higher weed pressure and use of acetic acid.
Publications
- Strik, B. 2009. Weed and fertility management of a newly established organic blueberry field. eOrganic Updates!, May 2009:3.
- Strik, B. 2009. Weed and fertility management of a newly established organic blueberry field. Proc. Northwest Center for Small Fruits Research, Dec., 2008, Corvallis, OR 17:43-45
- Strik, B. and H. Larco. 2008. Weed and fertility management of a newly established organic blueberry field. Proc. Northwest Center for Small Fruits Research, Nov. 29, Boise, ID. 16:55-57
- Costello, Ryan. Composting and Blueberry Production. p. 15-16. In: Small Farm News. OSU Extension. Fall, 2009.
- Strik, B.C., G. Buller, H. Larco, and J. Julian. 2009. The economics of establishing blueberries for organic production in Oregon. A comparison of weed management systems. Acta Hort. 810:457-464
- Larco, H., B.C. Strik, D. Bryla, and D. Sullivan. 2009. Establishing Organic Highbush Blueberry Production Systems. The Effect of Raised Beds, Weed Management, Fertility, and Cultivar. HortScience (abstr.), 44:1120-21.
- Strik, B.C. 2009. Organic blueberry production: is it viable in the Northwest Proc. Lower Mainland Hort. Improvement Assoc., Abbotsford, B.C., Feb. 19-21: 135-136
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