Project Design

This blueberry production project is designed be economically sustainable and productive, but is also designed to provide new information and insights into best practices of organic blueberry production.

Experimental Designs

• A Simple Design
  

  Compost Treatments	Mulch Type/Style	Conventional Blueberry Plant #	Organic Blueberry Plant #	# of Different Cultivars
  Horse Manure & Sawdust	Wood chips / Raised beds	0	32	5
  Horse Manure & Sawdust	Wood chips / Mounded beds	19	22	5
  Sheep  Manure & Hay	Wheat straw / Raised beds	0	24	5
  Sheep  Manure & Hay	Wheat straw / Mounded beds	0	23	5
  Pine  Straw	Pine straw / Mounded beds	0	22	4
  Prof Mulch	Prof mulch / Mounded beds	0	33	5
  	Totals	19	156
  		Total # Blueberry Plants:	175

• Assessment Groups
  

  Experimental  Treatments
  Approach	Organic	Conventional (not-organic)
  Compost Treatments	House Manure & Sawdust	Sheep Manure &  Hay	Pine Straw & Chips	Planters' Choice
  Covering Mulches	Wood chips	Wheat straw	Pine straw	Planters' Choice
  Bed Styles	Raised oak beds: 8-10 inches mulch	Mounded beds: 4-5 inches mulch

Experimental Design Details

• Compare organic versus conventional (non-organic) production practices on blueberry plants considering the following aspects:
  • economics
  • plant health and vigor
  • productivity
  • resistance to disease and insects.
• Contrast the suitability of five blueberry cultivars for our area of the Shenandoah Valley
• Determine the cost/benefit and productivity values of three introduced growing practices on the organic plot:
  • mounded versus low-raised bed borders
  • drip irrigation versus restricted supplemental water

Quantifiable Measures

• Economics or cost analysis of the varied aspects of blueberry growing including:
  •  soil preparation,
  • soil amendments, compost types, & fertilizers,
  • mulch,
  • equipment costs,
  • purchase of cultivars,
  • insecticides and predation control,
  • labor,
  • harvesting and marketing expenses, and
  •  income from produce sales.
• Periodic measures of soil conditions (student measured values compared with results from professional soil testing laboratory at Virginia Tech) for values including:
  • soil respiration and infiltration
  • pH
  • content of major chemical elements: nitrogen, phosphorus, and potassium
  • content of minor chemical elements: calcium, magnesium, zinc, manganese, copper, iron, and boron.
  • quantity of humus
  • quantity of organic matter
• During mid-summer determine annual foliar measures of nutrients and trace elements from mature leaves taken from various representative plants.
• Determine early measures of plant health including:
  • growth (two direct measures of plant growth) via
    • Branch relative growth rate (RGR) of three selected representational primary branches labeled on a given plant that will be measured at least twice--once in early spring and then again in the fall prior to pruning--using the following formula: Branch RGR = (BLf-BLs / BLs) x 100 where
      • BL = branch length (cm)
      • s = spring measure
      • f = fall measure
    • Plant growth index (GI) where GI = plant height x width in row x width across row.  Minimally measured twice: spring and fall
  • plant physiology by measuring carbon dioxide assimilation (photosynthesis) and water transpiration (stomatal conductance) using infrared gas analysis (IRGA)
• Determine ultimate measures of productivity via:
  • number of blooms per plant
  • marketable berry yields per plant
  • size of individual berries
  • berry flavor
• Two other paired group comparisons
  • Impact of high hoop covered horticulture versus no hoops on plant health and berry production on organic plantings.
  • Impact of low raised beds versus rounded beds on plant health, weed & pest control, and productivity on organic plants.

 

April 2009 Photograph of Organic Blueberry plots (south view) with rye planted on rows and grass middles between rows.

June 2009 Photograph of Organic Blueberry plots.  Rows cultivated and compost added.

Plot Plans

Organic Blueberry Plot Plan

April 2010 Version

Conventional Blueberry Plot Plan

April 2010 Version

April 2009 Conventional Blueberry Plot (rows), not-organic with rye cover crop on rows (recently mowed) and grass middles between row.

April 2009, Conventional (not organic) blueberry plots cultivated with compost, soil amendments and grass middles

Spring 2010 Blueberry Project Plots

These photographs were taken on June 2, 2010 and reflect the condition of the various blueberry plots at that time.

Overview of the Organic Blueberry Plot (06/02/2010).  Note the valves controlling the drip irrigation system in the front right side of the photograph.

Average appearing Organic Plot Blueberry on June 2, 2010

Overview of the Organic Blueberry Plot (06/02/2010).  Note the valves controlling the drip irrigation system in the front right side of the photograph.

 

First Year Project Report on USDA Specialty Agriculture Project: 3/9/2010

Activities/Targets/Performance Goals

During 2009, the primary activities at Knoll Acres, the site for the sustainable organic blueberry operation consisted of two major items: (1) soil preparation for planting blueberries and (2) planting 179 three-year old bare rooted blueberry plants representing five cultivars.  At EMU science laboratories, student researchers conducted soil testing and foliar analyses.

Overview of Experimental Plot Design and Field Research Site at Knoll Acres.  Selected blueberry plots at Knoll Acres consist of Frederick and Lodi cherty silt loams with 15 to 45% slopes.  The surface layer of this soil consists of a dark grayish brown cherty silt loam about six inches thick with a deeper layer of 6 to 13 inches of a strong brown clay loam.  The substratum is brownish yellow silty clay to a depth of 72 inches or more.  Both the surface layers and the subsoil contain numerous rocks which make cultivation difficult.  Both the high rock content and the elevated slopes minimize the productivity of this land for commercial row crops.  Consequently much of this land is either in permanent native pasture or in oak/hickory forests.  By selecting a hillside portion that was once in permanent native pasture, this project models an alternative use for this land by enhancing its productivity through organic practices for blueberry production.

Soil preparation at Knoll Acres.  In August 2008, an organic blueberry production plot and a conventional blueberry production plot were selected.  The conventional plot is located about 150 yards from the organic plot and is separated by a house and paved driveway. Rows, running north to south along the slope, were cultivated within each plot, rocks picked up, and soil samples taken for testing.  An initial treatment of elemental sulfur (1 lb sulfur/ 50 sq ft) was applied to the rows and a cover crop of annual rye was planted.  Initial soil testing showed an average soil pH of 6.6 with adequate macro- and micronutrients in the soil. 

During April/May 2009, rows of the organic plot were grouped into one of four soil compost treatments: (1) horse manure compost, (2) sheep/goat manure compost, (3) pine needle/bark compost, and (4) Planters’ Choice compost.  Conventional (non-organic) plot rows were treated with horse manure compost.  Specific composts were added to their designed rows and incorporated into the soil via additional tillage.  Additional rocks were removed.  Row middles, of native pasture grass, were periodically mowed during the summer and fall months.  In June/July 2009, rows were re-tilled with a chisel plow, sulfur reapplied (5 lb /100 sq ft), and organic soil amendments were added to all rows: Azomite (3.5 lbs/100 sq ft), fish meal (2 lb/100 sq ft), rock phosphate (2 lb/100 sq ft), green sand (4 lbs/100 sq ft), Holly Tone (5 lb/100 sq ft) and peat moss (2 cu ft/100 sq ft).  To examine potential effect of deep mulching, raised wooden bed sides (11.5 inches high) were constructed in July 2009, for parts of the organic horse manure and sheep/goat manure compost rows.  During September/October, rows were rotor-tilled for weed control, rocks removed, elemental sulfur reapplied to all rows (5 lbs/100 sq ft), and a second treatment of compost incorporated into the designated rows.  Bed borders (4” high) were constructed for the remaining portions of the organic rows.  Beneficial biological organisms, milky spore disease powder and beneficial nematodes (Hb/Sc) were applied to selected organic rows.  Finally soil samples for analysis from the various treatment plots were taken in November 2009.

Table 1. Blueberry cultivar planting and soil treatment plots

Soil Amendments Added	Mulch Type / Style	Conventional Blueberries: # plants [# cultivars]	Organic Blueberries: # plants [# cultivars]
Horse Manure compost	Pine bark mulch / high raised beds	0	28 [5]
Horse Manure compost	Pine bark mulch / mounded beds	19 [5]	26 [5]
Sheep/Goat Manure compost	Pine bark mulch / high raised beds	0	24 [5]
Sheep/Goat Manure compost	Pine bark mulch / mounded beds	0	23 [5]
Pine Straw/Bark compost	Pine bark mulch / mounded beds	0	23 [5]
Planters Choice compost	Pine bark mulch / mounded beds	0	36 [5]
		19 total	160 total

 

 

 

 

 

 

 

 

 

Blueberry planting at Knoll Acres.  During late November and early December, 179 blueberry plants representing five cultivars (Duke, Blue Crop, Jersey, Chandler, and Bluegold) were planted at Knoll Acres in various treatment plots.  Planting holes (approximately 24”x10”), at 5 foot intervals in the middle of the row, were hand dug.  Dormant bare-rooted 3 year old blueberry plants were planted in the moistened holes, using a mix of soil, shredded pine bark, and peat moss as covering material. After planting, the blueberries were mulched with 3-4 inches of shredded pine bark and left to over-winter. 

Figure 1. Photograph of the organic plots at Knoll Acres with planted blueberry cultivars.  Rows are laid out running from north to south (left to right in the photograph); the darker gray in the upper eight rows (upper left side of photo) shows the sides of the high raised beds.

Two organic plots (Horse manure compost & Sheep/goat manure compost) were subdivided to determine the effect of using high raised beds with deep mulch (11-12 inches deep) in contrast to shallow mulch (3-4 inches deep) in rounded beds; the deep mulch will be applied in the spring of 2010.  All blueberry plants were mulched with 3-4 inches of shredded pine bark and left to over-winter (Figure 1). 

Soil Testing Results.  To monitor soil conditions, periodic soil testing were done and compared across the various treatment plots.  Routinely in our laboratory, EMU student researchers take multiple composite soil samples from each treatment plot to assay for macro- and micronutrient content.  These assays are done by using a LaMotte Professional Soil Test kit to test for soil levels of pH, nitrate, nitrogen, phosphorus, potassium, humus, calcium, magnesium, manganese, aluminum, nitrite nitrogen, sulfate, chloride, and ferric ion. Quality controls include periodically sending parallel samples to the Virginia Tech Soil Testing laboratory for their analysis.  In assessing adequate soil nutrients, we also consider the foliar macro- and micronutrient values from the blueberry cultivars themselves.  Table 2 shows soil macro- and micronutrient levels from three soil sampling dates: 8/08, 4/09 and 11/09.

Soil amendments and compost, added to treatment plots within a few months following the 4/09 soil samples, resulted in significant increases in macro- and micro-nutrient content in all the plots.  Organic matter (%) increased substantially in all organic plots.  Initial organic matter (%) of the conventional plot was substantially higher than in the organic plots; however, after the compost treatments, all of the organic plots have higher levels of organic matter than the conventional plot.  While all plots were treated with sulfur, the pine needle/bark compost plot demonstrated the earliest response with a lower pH (decreasing from 6.6 to 5.2).  In most of the other organic plots, adding composts with neutral pH, minimize an early soil response to sulfur treatment.

Table 2. Treatment Plot Soil Testing Values: Macro and Micronutrients

Plot Lot	Dates	P (lb/A)	K (lb/A)	Ca (lb/A)	Mg (lb/A)	Zn (ppm)	Mn (ppm)	Cu (ppm)	Fe (ppm)	B (ppm)	pH	Organic matter (%)
Organic: Horse manure compost	08/08 04/09 11/09 4/10	56 107 939 580	381 451 2234 634	3882 4771 4327 4807	324 351 884 843	4.8 6.0 13.0 13.5	43.9 42.1 62.7 54.8	0.9 0.1 0.1 0.1	5.9 4.7 10.6 9.6	0.5 0.6 0.9 1.0	6.6 6.8 6.8 5.8	-- 5 11.8 15.3
Organic: Sheep/Goat manure compost	08/08 04/09 11/09 4/10	56 107 867 786	381 451 3442 754	3882 4771 4900 5665	324 351 1002 1031	1.8 6 11.3 14.7	43.9 42.1 64.9 64.5	0.9 0.1 0.1 0.1	5.9 4.7 4.9 5.6	0.5 0.6 1.2 1.3	6.6 6.8 7.1 6.2	-- 5 8.7 14.9
Organic: Pine needle /bark compost	08/08 04/09 11/09 4/10	56 38 186 160	381 223 467 189	3882 1911 2004 1445	324 198 265 138	4.8 3.2 4.8 6.3	43.9 35.2 53.0 117.6	0.9 0.2 0.3 1.1	5.9 4.1 6.0 12.8	0.5 0.4 0.5 0.3	6.6 6.8 5.2 4.5	-- 4 7.1 10.6
Organic: Planters choice compost	08/08 04/09 11/09 4/10	56 38 596 582	381 223 1777 595	3882 1911 3948 4854	324 198 966 989	4.8 3.2 10.1 11.7	43.9 35.2 58.5 58.8	0.9 0.2 0.1 0.1	5.9 4.1 4.3 4.9	0.5 0.4 1.5 1.4	6.6 6.8 7.3 6.4	-- 4 13.2 21.5
Conventional: Horse manure compost	08/08 04/09 11/09 4/10	296 167 489 375	206 315 985 427	4639 5282 2809 3090	682 424 483 445	16.3 7.3 6.7 10.3	26.7 47.5 40.6 65.7	0.1 0.1 0.2 0.1	5.5 5.0 10.4 13.1	0.9 0.8 0.6 0.5	6.9 7.2 6.2 4.8	-- 8.8 6.9 14.7

The infield measures for soil respiration, water infiltration, pH, and electroconductivity, were based on the USDA Soil Quality Test Kit Guide protocols.  Initial results (Table 3) are based on multiple measures taken from soil treatment sites at Knoll Acres in November, 2009.  In summary at that time, respiration levels in the conventional plot were about 50% of the levels in the various organic plots.  Electroconductivity values were the highest in the organic sheep/goat manure compost plot and the lowest in the pine needles/bark compost plot.  Additional measurements of these soil quality indicators (as well as of macro- and micronutrient levels) will be taken biannually during each growing season.  Comparative results will help us monitor the soil character of the various treatment plots.  As illustrated by the water infiltration rates, the porosity of the soil in all plots was high.

Table 3.  Soil Quality Indicators: Average Values/Treatment Plot (November 2009)

Plot	Respiration (lbs CO2-C/acre/day)	Water Infiltration (secs)	Electroconductivity (dS/m)
Organic: Horse manure compost	16.5	3.4	1.84
Organic: Sheep/Goat manure compost	21.7	7.5	4.31
Organic: Pine needles/bark compost	14.5	6.0	0.56
Organic: Planters Choice compost	17.7	13.6	1.82
Conventional: Horse manure compost	8.1	4.1	1.30

Plant foliar nutrient analyses.  In April and August 2010, foliar samples from specific cultivars within various treatment plots will be measured for Fe, Zn, Mn, Cu, Ca, and Mg with the following modified method, using flame atomic absorption spectrophotometry (FAAS).  Composite foliar samples are dried in an oven at 95o C, homogenized, and 0.25 g sample digested with 5.00 mL 6 M HCl for 15 minutes at 70o C. Solutions are filtered using Whatman No. 2 paper and diluted to 50.0 mL with distilled water.  Concentration of the solutions, later converted to mg element/kg dry leaf mass, are determined by FAAS with the Varian AA240FS Fast Sequential Atomic Absorption Spectrometer using standard curves prepared from elemental reference solutions. The set-up includes 3 Varian hollow cathode lamps: multi-element Fe/Cu/Mn/Co, multi-element Ca/Mg, and Zn.

As an illustration of the application of this technique blueberry leaf samples, taken from older established Blueray and Jersey plants at Knoll Acres (fall of 2009), were analyzed for the elements Fe, Zn, Mn, Cu, Ca, and Mg using flame atomic absorption spectrometry (FAAS).  This sampling was from plants growen in identical soil treatments.  However, results of this trial, seen on Table 4, reflect cultivar differences especially in foliar content of some micro-nutrients.

Table 4. Average concentration, in mg element/kg dry leaf mass, of foliar micronutrients of blueberry cultivars 'Blueray' and 'Jersey'.

Cultivar	Fe (ppm)	Zn (ppm)	Cu (ppm)	Mn (ppm)	Ca (ppm)	Mg (ppm)
'Blueray'	271	30	12	123	9483	5175
'Jersey'	22	15	12	99	5593	3444

Project Goals.  The grant proposal described five project goals which are summarized here: (1) Illustrate and promote this small commercial organic blueberry production as a model system of sustainable specialty crop that has economic viability; (2) Determine best organic practices in developing a blueberry operation including soil preparation, …, selection of fertilizers and mulch, usage of low/raised bed borders, etc. ; (3) Install a hoop system over a portion of the blueberries; (4) Control bird predation and provide supplemental water with drip irrigation; and (5) Provide academic educational experiences for undergraduate students.

During the first year of this proposal, we have developed the groundwork for project goal #1.  Analysis of blueberry plant growth and vigor, scheduled for this coming year, will provide outcome data that can be integrated with establishment efforts.  We are in the process of beginning official organic certification with Global Organic Alliance.  Goal #2 has also been initiated via soil plot preparation using varied compost materials, monitoring soil characteristics, establishment of raised beds and low bed borders, and planting 179 blueberry plants representing five cultivars.  Goal #3 has not been initiated yet, but plans are to do so during the summer of 2010.  Goal #4 is partially completed.  A 1600 gallon storage tank is installed; a gravity flow drip irrigation system has been purchased and will be installed during May 2010.  Construction of supports for bird netting system will be done during the summer of 2010 in preparation for the harvesting a first crop in 2011.  Finally, goal #5 is well underway with multiple students participating in this project.

Measurable Outcomes.

Monitoring website.  A website (www.knollacresblueberries.com), designed by the project director, was functionally on-line in September 2009.  This site was periodically updated with information about on-going projects and interim reports. The website is currently operational and primarily focuses on the preparation portion of this project.  During the past several months the website received an average of 600-800 unique visitors per month.

Student Independent Research Projects.  Currently, a senior EMU student, Jeremiah Vallotton, is concluding a soil testing project that assesses the impact of various soil treatments on soil parameters during the past nine months.  Another senior EMU student, Allison Glick, developed the foliar assay protocol using flame atomic absorption spectroscopy this past year.  Both Vallotton and Glick will be presenting their preliminary results at the Virginia Academy of Sciences Annual Meeting in May 2010.  Finally, two students, who are rising seniors at EMU, Denay Fuglie and Braydon Hoover, will be assessing plant vigor and response during the summer of 2010 by determining measures of plant growth, quantitative measures of plant physiology (photosynthesis and stomata conductance), and foliar elemental macro- and micronutrient analysis.  Funds from the grant will provide partial support for the activities of these four students.

Biology laboratory class.  During July of 2009 under the guidance of the project director, seven EMU incoming first-year undergraduate students carried out mini-research soil testing projects comparing two organic soil treatments.  Each student wrote a mini-report depicting her/his findings.  This work was a part of EMU’s Summer Bridge Scholarship program for incoming students who are majoring in some area of science or mathematics.

Data dissemination.  Currently, two presentations co-authored by student participants are planned for the upcoming annual meeting of the Virginia Academy of Sciences in May 2010.  Additional and fuller publication work will occur during the second year of the project.

Delays and Developments

Three construction items remain to be completed during the summer of 2010: (1) installation of the hoop system over a portion of the planting; (2) completing the installation of the drip irrigation system; and (3) installation of the supports for bird netting to control predation.  Analysis of the blueberry plant responses to soil treatments await plant maturation and development.  Initial studies of plant vigor and physiology are scheduled for this summer.

While a couple of presentations are scheduled that describe on-going work, most of the publication out-come minimally requires the completion of a growing season, the summer of 2010.  Consequently, preparation of articles and a manuscript is scheduled for the winter of 2010-2011.

Since the current grant proposal is focused on “creating conditions” for blueberry production and is limited to a two-year time period, the project director believes that this project can be more valuable with extended study and monitoring that considers plant productivity and the marketing of berries.  A sustainable economic operation is dependent on a cost benefit analysis that considers not only start-up costs but also economic yields from the market place.  Consequently, the project director spent most of the past six weeks writing a larger three-year integrated project standard grant proposal to the USDA entitled, “Analysis of Sustainable Organic Blueberry Production in the Shenandoah Valley of Virginia.”  This proposal is built on the on-going work of this current grant.  If it is funded, the grant will enable analysis of productivity outcomes that specifically contrasts organic versus conventional practices.

Work for the Coming Year

Time/Line.

• March 2010.  Prune broken branches (due to heavy snow) from planted blueberries; apply deep mulch to high-raised bed areas.
• April 2010. Repeat soil testing in different treatment plots; do first foliar elemental analysis; conduct plant physiology experiments.
• May 2010. Complete direct plant measures to assess plant growth and vigor.  Complete installation of drip irrigation system.
• June 2010. Erect supporting system for bird netting over all plots.  Quantify fruiting characteristics of specific cultivars in contrast to soil treatment plots.
• July/August 2010.  Erect hoop system over a sub-portion of the organic blueberry plot.  Resample plants for foliar elemental analysis, repeat plant physiology experiments.
• September/November 2010.  Analyze data obtained over the summer months.  Prepare abstracts of results for presentation at professional conferences. ·         December 2010.  Prepare two articles for publication in trade magazines and one manuscript for publication in peer reviewed journal.
• January/February/March 2011.  Conclude current grant project.  Write up final report.  Develop another grant proposal to extend this project.

Mouse Blueberry Consumption Pilot Study

January 2010 - May 2010

Objective: Assess the blueberry consumption characteristics of Swiss mice, monitor dietary changes, body and organ weight changes, and tissue uptake of anthocyanins.

Experimental Design

Place 30 day old Swiss mice in one of four treatment groups:

• CON: Control. Give normal rodent chow and water free choice

• JUA: Blueberry Juice only. Give normal rodent chow and 10% blueberry juice free choice; no water.

• BBC: Blueberry choice.  Give normal rodent chow and water free choice and also provide supplemented whole blueberries free choice

• JUC: Blueberry juice choice.  Give normal rodent chow and water free choice and also provide supplemented 10% blueberry juice free choice.

Maintain mice on diets for 40 days; monitor body weight changes, consumption of water, rodent chow, and blueberry juice or whole blueberries.

When mice are 70 days old, necropsy and remove serum, liver, and jejunum to assay for anthocyanin content. (Freeze samples.)  Weigh kidney, testis, seminal vesicle, epididymal fat, and testis.  Freeze testes for sperm quantification.

Results:

Under construction......

 

 

Established Blueberries

• About 8 years ago (2000), we planted six blueberry plants for home use: 2 Coville, 2 Blueray, and 2 Jersy

• April 2009, Established Blueberries in bloom

• Late June 2009, Established Blueberries with berries