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The long-term goal of this project is to develop organic production systems for highbush blueberry that maximize plant growth, yield, and fruit quality; facilitate weed, water and nutrient management; and provide economic benefit to growers. Research objectives of this project are: <OL> <LI> Evaluate organic weed management, fertility, and production systems for effectiveness and impacts on shoot growth and production, root distribution, and availability of water and nutrients; <LI>Develop a compost specifically designed for blueberry that will provide a long-term boost in soil N mineralization potential without causing damage to plants due to high pH and/or high salts.</OL> Extension and outreach objectives of the project are to: <OL> <LI>Develop economic enterprise budgets for establishment and management of organic blueberries as affected by production method.<LI>Produce workshops, field days, publications and web-based tools to effectively disseminate research findings to industry. <LI>Use eOrganic to facilitate involvement of clientele during the project, and to package our research findings and traditional Extension activities into products that are useful to a national audience;<LI>Assess changes in grower knowledge, intentions, and practices resulting from the project.</OL> Measurable research outcomes for the Integrated Systems Trial will be in the form of answers to these questions:<OL> <LI> What is the most effective way to control weeds? <LI> Can we use weed mat to substitute for sawdust mulch (industry standard practice) for weed control? <LI> What fertility inputs can be used to supply the crop with adequate nitrogen? <LI> Can compost be used as a fertility source in organic production? <LI> Do blueberries need to be grown on raised beds? <LI> What impact will altered production practices have on long-term plant health and sustainability? <LI> Can blueberries be grown economically using the recommended sustainable organic production systems? </OL>Each year, the project advisory group will meet and conduct a group assessment of project progress. Specifically, the advisory group will review project outcomes to date, and discuss future project opportunities and obstacles. Based on advisory committee inputs, our plan of work will be adjusted for the next year, as necessary. <P>Measurable short-term and medium-term outcomes of this project have been discussed with the project advisory committee, and have been considered in the planning process. Short-term outcomes will include changes in knowledge, skills, attitude, motivation, awareness. Medium-term outcomes will include changes in behaviors, practices, policies, procedures. Short and medium term outcomes will be assessed by participant surveys at outreach events. In the final year of the project, blueberry industry participants will be surveyed to assess short and medium term project outcomes.
Non-Technical Summary: The goal of this project is to develop an organic production system for highbush blueberry that maximizes plant growth and yield; facilitates weed, water, and nutrient management; and provides the greatest economic benefit to growers. This proposal responds to research needs identified by growers and university personnel. To achieve our goals, the following objectives were developed: 1) evaluate effectiveness and impacts of organic weed management, fertility, and production systems; 2) develop a ocustomo compost; 3) develop economic enterprise budgets; 4) disseminate research findings to industry; 5) use eOrganic to facilitate clientele involvement and package our findings for a national audience; and 6) assess changes in grower knowledge, intentions, and practices resulting from the project. Our advisory committee (industry and research members) has been involved in selecting the site, developing objectives and treatments, and management. This project seeks to add greater scientific depth to our knowledge of best practices for organic blueberry production. Treatments consist of 2 cultivars (Duke and Liberty), 2 production methods (raised bed or flat ground), 3 weed management practices, and 2 types and rates of organic fertilizer. From 1995 to 2005, worldwide highbush blueberry acreage increased by 90%. The market for organic blueberries is very strong. However, there were only an estimated 194 ha of organic blueberries in North America in 2003, less than 1% of total. Even with record prices for blueberries in 2006 and 2007, organic prices were 20-50% higher than conventional. In 2003, a survey we conducted indicated that weed management was one of the top challenges nationwide. Organic mulches have been shown to be effective at controlling many annual weeds. However, using organic mulches, particularly those with a high C:N ratio, complicates management of plant fertility. Our research has shown that in plantings on raised beds, irrigation management and mechanical weed control is more difficult. Research is needed on the impact of raised and flat ground plantings on weed management and blueberry plant growth and yield. We have looked at the impact of mulch on nutrient uptake and have provided growers with revised fertilizer recommendations. However, we have not assessed whether these findings can be extrapolated to organic production systems. Can we use similar rates of organic sources of N? What are the best timings of application to ensure the fertilizer N is available when the plant needs it? How will mulch type impact fertilizer availability? Will the compost we apply provide any measurable advantage in this production system? After this study, we will have science-based information on how growers might be able to establish and manage organic blueberries. We will have concrete information on the effectiveness of organic weed management techniques and fertilization methods. We will also be able to provide advice on the irrigation requirements of flat ground and raised bed planting systems as affected by mulching or weed mat. We will maintain detailed records in order to be able to provide some economic cost/benefit analyses. <P> Approach: Integrated Systems Trial: Treatments consist of 2 cultivars (Duke and Liberty), 2 production methods (raised bed or flat ground), 3 weed management practices [sawdust mulch+hand weed removal; compost+sawdust mulch+acetic acid; and weed mat], and 2 types and rates of fertilizer (feather meal and liquid fish emulsion at 28 or 55kgN/ha). Plants are drip irrigated. Design is a split-split plot with 5 reps and 240 plots. Each sub-subplot is 4.6-m long with 6 plants at 0.76 m apart, planted Oct. 2006. Soil samples will be collected annually and bulk density 2x per year. Weed pressure as coverage will be recorded every 3 weeks. One plant/plot will be destructively harvested and dry weight determined and shoot growth will be evaluated each season. Root samples will be collected periodically by using root in-growth cores to estimate standing root biomass and vitality. Images of roots that grow along the surface of minirhizotron tubes will be recorded and analyzed for root production and root longevity. Soil temperature will be measured. Soil water dynamics will be measured using a time-domain reflectometry (TDR) system. To determine the distribution of mineral nutrients in each treatment, soil solution samplers (Rhizon Samplers, Soilmoisture Equipment Corp.) will be installed near each TDR probe. Soil solutions will be collected weekly and analyzed. We will use ion-exchange membranes [Plant-Root Simulator probes (PRS), Western Ag Innovations, Saskatchewan] to assess treatment effects on nutrient supply rates to plant roots. The water and nutrient status of the plants will be monitored seasonally using tissue analyses and a pressure chamber. Yield, berry weight, and firmness will be obtained by hand harvesting. We have collected accurate data on the costs of establishment and are recording labor requirements and products throughout for an economic analysis by treatment. At the completion of this project, we will produce an organic blueberry enterprise budget and interactive spreadsheet for the A Grower's TEAM software program. Custom Compost Trials: We will use combinations of locally-available byproducts to create a suitable compost. In a screening study, compost feedstock mixtures will be enclosed in porous nylon mesh bags, placed within a large hot compost pile, and harvested periodically to determine compost chemical characteristics. We will leach selected finished composts with water and use the leachate to irrigate containerized blueberry plants, evaluating survival and root health. We will conduct lab incubations with soil to determine compost decomposition rate and plant-available N release. Finished composts will be incubated in soil to determine decomposition rate and release of plant-available N, and incubated and leached repeatedly to determine nutrient concentration, pH, and salts in the leachate. Select compost mixtures will be evaluated in the field by planting blueberries in compost-amended soil or soil mulched with the compost. The data for this split-split plot design will be analyzed using Proc Mixed, analysis of variance or repeated measures, as appropriate.