Bernadine C. Strik1, Renee Harkins2, David Bryla3, and Gil Buller4

1Professor, Dept. Horticulture, OSU.; 2M.S. Student, OSU; 3USDA-ARS, Corvallis; 4Senior Research Assistant, NWREC/OSU

Introduction 1

Methods 2

Results 3

Conclusions 4

Future Work 5

The purpose of our study is to investigate the effects of organic management on plant and soil nutritive status, dry matter accumulation, and plant growth in organic trailing blackberry. While there is research describing how conventional production systems impact trailing blackberry nutrition and physiology (Makus, 2007, Andersen and Crocker, 2008, Bell et al., 1995), there is a gap of knowledge on how to manage organic trailing blackberry systems to achieve vigorous plants and high yield and quality. The objectives of this study are to determine the ideal: 1) irrigation schedule and 2) weed management system for two popular, trailing cultivars, ‘Marion’ and ‘Black Diamond’, grown in a machine-harvested, organic system.

Treatments Treatment

1. Trailing blackberry cultivars 1. ‘Black Diamond’ 2. ‘Marion’

2. Weed management 1. Weed mat 2. Hand weed 3. Control

North Willamette Research and Extension Center, Aurora, OR

•0.4 hectare planting, established June 2010 •5 replicates of 120 split-split plots •Four plants per plot at 1.5 m x 3 m spacing •Two non-treatment guard rows •A cereal rye/common vetch (Secale cereale/ Vicia sativa) cover crop in alleys •Single lateral drip tube either suspended on trellis or under weed mat •Plants were cut back to crown in February 2011 to increase growth and vigor •Weeds in hand-weeded plots were removed on two dates in spring 2011 •July 2011, weeds in non-weeded plots were cut and residue left on surface of respective plots •Plants trained on two-wire trellis system as they grew in summer 2011

Our findings suggest that during the study period of June 2010 to March 2011, weed management treatments did not significantly affect plant nutrient status, but did affect plant water potential and soil nutrient status. In particular, weed mat plots required more irrigation than hand weed or control plots. Soil pH tended to be lowest in hand weed plots and in areas directly in the planting row, which agrees with findings from Haynes (1990). Overall, findings to date suggest that weed management may directly affect soil and plant nutrient status, but it is unclear at this point whether weed management will impact berry nutrient status.

Andersen, P.C. and Crocker, T.E., 2008. Blackberry and Raspberry, HS807. Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainsville. Bell, N.C., Strik, B.C., and Martin, L.W., 1995a. EFFECT OF PRIMOCANE SUPPRESSION DATE ON MARION TRAILING BLACKBERRY .1. YIELD COMPONENTS. Journal of the American Society for Horticultural Science 120:21-24. Haynes, R.J., 1990. MOVEMENT AND TRANSFORMATIONS OF FERTIGATED NITROGEN BELOW TRICKLE EMITTERS AND THEIR EFFECTS ON PH IN THE WETTED SOIL VOLUME. Fertilizer Research 23:105-112. Makus, D.J., 2007. Use of Fabric and Plastic Barriers to Control Weeds in Blackberries p. 95-103. In: Agriculture, U. S. D. o. (ed.), Subtropical Plant Science. Agricultural Research Service, Weslaco.

References

Study Site

On October 7, 2010 and again on October 14, 2011, soil samples were collected in a grid pattern (Fig. 7) to determine the influence of fertilization on soil nutrient status and pH. A full soil sample, taken on October 7, 2011, showed a cultivar effect on Mg, but no weed management effect on soil nutrient status.

Figure 3. Weed management, observed September 2011. A. Weed mat, B. Hand weed, C. Control

A. B.

C.

Acknowledgements The authors appreciate the funding provided by Northwest Center for Small Fruit Research, the Oregon

Organic Research Program, and NIFA-OREI.

We appreciate our academic cooperators: Diane Kaufman, Assoc. Professor, NWREC/OSU; Luis Valenzuela (OSU & USDA-ARS HCRL); Chad Finn (USDA-ARS HCRL); Vaughn Walton (OSU); John McQueen (OSU); and our Advisory Board members: Eric Pond (Riverbend Organic Farms., OR); Chrislyn Particka (formerly Sakuma Bros., WA); Joe Bennett (Small Planet Foods, WA); Tom Avinelis (Homegrown Organic Farms, CA); Derek Peacock (Hurst’s Berry Farms, OR); and Anthony Boutard (Ayers Creek Farm, OR)

Soil Nutrient Status

Plant Nutrient Status

Plant Water Potential

Figure 2. Hand hoeing plots, April 2011

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0 26-Jun 6-Jul 16-Jul 26-Jul 5-Aug 15-Aug 25-Aug 4-Sep 14-Sep 24-Sep 4-Oct

Leaf

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oten

tial (

Mpa

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Date

Average Leaf Water Potential by Cultivar: 2011

Black Diamond Marion

Mean Leaf Tissue Nutrients 2011

N P Mg K Ca S B Fe Mn Cu Zn Al Cultivar (%) (%) (%) (%) (%) (%) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm)

Black Diamond 1.86 0.18 0.16 0.69 0.85 0.10 22.7 926.3 542.8 9.2 78.6 861.7

Marion 1.74 0.19 0.17 0.59 0.43 0.08 23.5 516.9 290.3 8.7 61.7 481.7

Cane tissue was collected on March 1, 2011 and again on January 24, 2012. Leaf tissue was collected August 18, 2011. All samples were analyzed for nutrients. No effects of weed management were observed, however cultivar and year were often significant indicators of plant nutrients.

Average primocane length, collected February 15, 2011 and again January 24, 2011 , was significantly affected by cultivar (p-value = 0.003 and p = <0.0001), but not weed management.

Fig. 6. Cane length measurements.

•In 2011, average pH tended to decrease with depth. Similar trends were observed for pH in 2010.

Fig 8. Sequential process of soil

sample collection.

A1 A2 A3 A4 A5

R3

R2

R1

Fig 7. Grid sampling locations used in 2010

and 2011.

•In 2010, there was a location by weed management interaction on soil pH. •In 2011, pH only varied significantly by location (p-value = <0.001; Fig. on left), suggesting that the weed management treatments tested may not significantly affect pH in established systems.

Given the observed yellowing of ‘Marion’ leaves in control plots (Fig. 5), we expected to see significant effects of weed management on leaf tissue N. While no significant effects were observed (p-value= 0.36), mean N was lower in ‘Marion’ leaves in control plots.

Fig. 4 March 1, 2011. Collection of primocanes for nutrient analysis.

Control Weed mat Hand weed

Leaf water potential, an indicator of plant water status, was measured weekly from July 7, to September 22, 2011.

•Plants in plots with weed mat required 30% more irrigation than hand weed or control plots.

•‘Black Diamond’ consistently had a higher leaf water potential than ‘Marion’ (see figure below).

Because plants did not fruit in 2011, we will begin berry nutrient analyses in Summer 2012. Additionally, we will measure the effects of post harvest and no-post harvest irrigation regimes as well as August and February training times on plants.

Fig. 1. Training primocanes June 14, 2011.

Fig. 5. ‘Marion‘ leaves for each weed management treatment on July 6, 2011.

Plant Nutrient Status Cont.

•Average soil temperature was highest in the weed-mat treatment, however there was no significant difference in soil temperature between any of the weed management treatments (p-value = <0.0001).

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Dec-10 Feb-11 Dec-11 Feb-12

Abo

vegr

ound

Bio

mas

s N

(g/p

lant

)

Aboveground Biomass Nitrogen Accumulations

Black Diamond Marion

Average Primocane Length

Cultivar 2011 Length (cm)

2012 Length (cm)

Black Diamond 5.70 3.29 Marion 8.38 6.94

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Tem

pera

ture

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Average Hourly Soil Temperature: 20 August 2011 Hand Weed Control Weed Mat

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Leaf

Wat

er P

oten

tial (

MPa

)

Date

Average Leaf Water Potential by Weed Management: 2011

Hand Weeded Non-Weeded Weed Mat

A A AB

AB BC

C C C

4.9

5.4

5.9

6.4

R1 A5 A1 A4 R3 R2 A2 A3

pH

2011 Mean Comparison of pH by Location

Samples integrated to 6” depth.

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Weed mat Hand weed Control

N (%

)

Mean 'Marion' Percent Leaf Tissue N

4.8 5

5.2 5.4 5.6 5.8

6 6.2

0.15 0.3 0.46

pH

Depth (m)

2011 pH by Depth Control Weed mat Hand weed

Collected at R1.

0.15 0.30 0.45