About 6000 ha of blackberry (Rubus L. subgenus Rubus, Watson) was harvested in the United States in 2012 [U.S. Department of Agriculture (USDA), 2014]. Oregon was the leading producer with 2500 ha, most of which were trailing types grown predominantly for the processed market (Strik and Finn, 2012; USDA, 2014). There were only 200 ha of organic blackberry harvested from certified and exempt organic farms in the United States in 2008, although worldwide production was 2500 ha (Strik et al., 2008; USDA, 2010). Consumer demand for organic products has been steadily increasing, creating a price premium for organic fruit and strong interest in organic production systems.
There is a growing body of research dedicated to blackberry growth and production (e.g., Strik and Finn, 2012), but there has been relatively little published on the organic production of blackberry. The Appropriate Technology Transfer for Rural America has published a general organic production guide that is mainly focused on small-scale production of erect and semierect types of blackberry for the fresh market with little information on the production of trailing types for the processed market (Kuepper et al., 2003). In organic trailing blackberry systems, Harkins et al. (2013, 2014) studied weed management and cultivar impacts during establishment, and Fernandez-Salvador et al. (2015a, 2015b) investigated several cultivar and fertilizer options.
Weed management can be one of the most challenging and expensive issues to address in organic production, as Organic Materials Review Institute (OMRI)-listed materials for weed control are limited, and removing weeds by hand is expensive. Therefore, some growers allow weeds to grow in organic blackberry plantings and remove them only before harvest. However, weeds compete with blackberry plants and can significantly reduce yield when left unmanaged (Harkins et al., 2013; Meyers et al., 2014). The use of a perforated landscape fabric, or “weed mat,” as a barrier to weeds within the blackberry row has been successful in blackberry plantings during establishment (Harkins et al., 2013; Makus, 2011; Meyers et al., 2014).
Most of the research published to date on trailing blackberry has been in ‘Marion’ or other older cultivars (Bell et al., 1995a, 1995b; Cortell et al., 1997a, 1997b; Julian et al., 2009; Mohadjer et al., 2001; Sheets et al., 1972; Takeda et al., 2002). However, many newer thornless cultivars, such as ‘Black Diamond’, are desirable to producers because they reduce training time and cane damage and eliminate the risk of finding thorny petioles in the machine-harvested, processed end product (Strik and Buller, 2002). Thornless cultivars of trailing blackberry are also reported to be cold hardier (Finn et al., 2005). ‘Marion’ and ‘Black Diamond’ together accounted for >75% of the 2914 ha of blackberry produced in Oregon in 2012 (USDA, 2013).
Trailing blackberry canes are typically trained onto a two-wire trellis in either late summer or late winter. Bell et al. (1995a) found that ‘Marion’ plants trained in August produced 46% greater yield than those trained in February. Despite the potential increase in yield, many growers still train in February, as canes left on the ground through the colder winter months are better protected from cold damage (Bell et al., 1992).
Irrigation practices in blackberry are varied. Most fresh market plantings are irrigated by drip irrigation, while blackberry grown for processed markets are most commonly irrigated using moveable pipe with overhead sprinklers or big gun systems (Strik and Finn, 2012; B.C. Strik, personal observation). Some growers in Oregon do not irrigate at all, even though blackberry plants have high water demands during fruit production (Bryla and Strik, 2008; Strik and Finn, 2012) and there is relatively little precipitation in summer (U.S. Department of Interior, 2013). There may be an option for an intermediate solution of turning off irrigation to blackberry after harvest instead of irrigating throughout the summer because irrigation demand drops off after fruit production (Bryla and Strik, 2008). Drip irrigation may be especially beneficial in organic production by reducing weed presence outside the drip zone and disease problems in the canopy when compared with overhead systems. Applying fertilizers through the drip irrigation system (fertigation) has worked well using OMRI-approved products in organic blackberry (Fernandez-Salvador et al., 2015a).
The objective of this study was to evaluate various production practices (cultivar, weed management, training time, and irrigation) for their effect on growth and organic production of mature trailing blackberry that were machine-harvested for the processed market. Two cultivars, ‘Marion’ and ‘Black Diamond’, were included in the study, along with three weed management strategies, nonweeded, hand-weeded, and weed mat. Two training dates, August and February, and two irrigation strategies, continuous summer irrigation and no irrigation after fruit harvest, were also included.
Archbold, D.D., Strang, J.G. & Hines, D.M. 1989 Yield component responses of hull thornless blackberry to nitrogen and mulch HortScience. 24 604 607
Bell, N., Nelson, E., Strik, B. & Martin, L. 1992 Assessment of winter injury to berry crops in Oregon, 1991. Agr. Expt. Sta. Spec. Rpt. 902, Oregon State Univ., Corvallis, OR
Bell, N.C., Strik, B.C. & Martin, L.W. 1995a Effect of primocane suppression date on ‘Marion’ trailing blackberry. I. Yield components J. Amer. Soc. Hort. Sci. 120 21 24
Bell, N.C., Strik, B.C. & Martin, L.W. 1995b Effect of primocane suppression date on ‘Marion’ trailing blackberry. II. Cold hardiness J. Amer. Soc. Hort. Sci. 120 25 27
Bryla, D.R. & Strik, B.C. 2007 Effects of cultivar and plant spacing on the seasonal water requirements of highbush blueberry J. Amer. Soc. Hort. Sci. 132 270 277
Capinera, J.L., Cranshaw, W.S. & Hughes, H.G. 1986 Suppression of raspberry crown borer, Pennisetia marginata (Harris) (Lepidoptera: Sesiidae) with soil applications of Steinernema feliae (Rhabditida: Steinernematidae) J. Invertebr. Pathol. 48 257 258
Cortell, J.M. & Strik, B.C. 1997a Effect of floricane number in ‘Marion’ trailing blackberry. I. Primocane growth and cold hardiness J. Amer. Soc. Hort. Sci. 122 604 610
Cortell, J.M. & Strik, B.C. 1997b Effect of floricane number in ‘Marion’ trailing blackberry. II. Yield components and dry mass partitioning J. Amer. Soc. Hort. Sci. 122 611 615
Crandall, P.C., Allmendinger, D.F., Chamberlain, J.D. & Biderbost, K.A. 1974 Influence of cane number and diameter, irrigation, and carbohydrate reserves on the fruit number of red raspberries J. Amer. Soc. Hort. Sci. 99 524 526
DeFrancesco, J., Edmunds, B. & Bell, N. 2015 Cane fruit pests: Raspberry crown borer. In: C.S. Hollingsworth (ed.). Pacific northwest insect management handbook [online]. Oregon State University, Corvallis, OR. 4 Apr. 2015. <http://insect.pnwhandbooks.org/small-fruit/cane-fruit/cane-fruit-raspberry-crown-borer>
Goode, J.E. & Hyrycz, K.J. 1968 The response of Malling Jewel and Malling Exploit raspberries to different soil moisture conditions and straw mulching J. Hort. Sci. 43 215 230
Fernandez-Salvador, J., Strik, B.C. & Bryla, D.R. 2015a Liquid corn and fish fertilizers are good options for fertigation in blackberry cultivars grown in an organic production system HortScience. 50 225 233
Fernandez-Salvador, J., Strik, B.C., Zhao, Y. & Finn, C.E. 2015b Trailing blackberry genotypes differ in yield and postharvest fruit quality during establishment in an organic production system HortScience. 50 240 246
Finn, C.E., Yorgey, B.M., Strik, B.C., Hall, H.K., Martin, R.R. & Qian, M. 2005 ‘Black Diamond’ thornless trailing blackberry HortScience. 40 2175 2178
Harkins, R.H., Strik, B.C. & Bryla, D.R. 2013 Weed management practices for organic production of trailing blackberry: I. Plant growth and early fruit production HortScience. 48 1139 1144
Harkins, R.H., Strik, B.C. & Bryla, D.R. 2014 Weed management practices for organic production of trailing blackberry: II. Accumulation and loss of biomass and nutrients HortScience. 49 35 43
Hoppula, K.I. & Salo, T.J. 2006 Effect of irrigation and fertilization methods on red raspberry winter survival Acta Agriculturae Scandinavica Section B—Soil and Plant Science. 56 60 64
Jennings, D.L., Carmichael, E. & Costin, J.J. 1972 Variation in the time of acclimation of raspberry canes in Scotland and Ireland and its significance for hardiness Hort. Res. 12 187 200
Judd, G.J.R., Gries, R., Teasdale, C. & Gries, G. 2012 Identification of a sex pheromone component for Pennisetia marginata (Lepidoptera: Sesiidae) Can. Entomol. 144 798 807
Julian, J.W., Seavert, C.F., Strik, B.C. & Kaufman, D. 2009 Berry economics: Establishing and producing Marion blackberries in the Willamette Valley. Ore. State Univ. Ext. Serv. EM8773, Corvallis, OR
Krewer, G., Tertuliano, M., Andersen, P., Liburd, O., Fonsah, G., Serri, H. & Mullinix, B. 2009 Effect of mulches on the establishment of organically grown blueberries in Georgia Acta Hort. 810 483 488
Kuepper, G.L., Born, H. & Bachmann, J. 2003 Organic culture of bramble fruits. Horticultural production guide. Appropriate Technol. Transfer Rural Areas, IP022. Butte, MT
Lovett, H.A. 1921 The loganberry crown borer, Bembecia marginata (Harris), p. 199–120. In: Third Crop Pest and Hort. Report. Ore. Agric. Exp. Sta. 1915–1920. Corvallis, OR
McKern, J.A., Johnson, D.T. & Lewis, B.A. 2007 Biology and control of the raspberry crown borer (Lepidoptera: Sesiidae) J. Econ. Entomol. 100 398 403
Meyers, S.L., Jennings, K.M., Monks, D.W. & Mitchem, W.E. 2014 Effect of weed-free strip width on newly established ‘Navaho’ blackberry growth, yield, and fruit quality Weed Technol. 28 426 431
Mohadjer, P., Strik, B.C., Zebarth, B.J. & Righetti, T.L. 2001 Nitrogen uptake, partitioning and remobilization in ‘Kotata’ blackberry in alternate-year production J. Hort. Sci. Biotechnol. 76 700 708
Morris, J.R., Nelson, G.S., Kattan, A.A. & Cawthon, D.L. 1978 Developing a mechanized harvesting and production system for erect blackberries HortScience. 13 228 235
Morris, J.R. & Sims, C.A. 1985 Effects of cultivar, soil moisture, and hedge height on yield and quality of machine-harvested erect blackberries J. Amer. Soc. Hort. Sci. 110 722 725
Raine, J. 1962 Life history and behaviour of the raspberry crown borer Bembecia marginata (Harr.) (Lepidoptera: Aegeriidae) Can. Entomol. 94 1216 1222
Sheets, W.A., Bullock, R.M. & Garren, R. Jr 1972 Effects of plant density, training, and pruning on blackberry yield J. Amer. Soc. Hort. Sci. 97 262 264
Sims, C.A. & Morris, J.R. 1982 Effects of cultivar, irrigation, and ethephon on the yield, harvest distribution, and quality of machine-harvested blackberries J. Amer. Soc. Hort. Sci. 107 542 547
Takeda, F., Strik, B.C., Peacock, D. & Clark, J.R. 2002 Cultivar differences and the effect of winter temperature on flower bud development in blackberry J. Amer. Soc. Hort. Sci. 127 495 501
Teasdale, C., Rudd, G.J.R., Gries, R. & Gries, G. 2013 Evaluation of synthetic sex pheromone for monitoring and management of raspberry crown borer Pennisetia marginata (Lepidoptera: Sesiidae) Agr. For. Entomol. 15 285 293
Trinka, D.L. & Pritts, M.P. 1992 Micropropagated raspberry plant establishment responds to weed control practice, row cover use, and fertilizer placement J. Amer. Soc. Hort. Sci. 117 874 880
U.S. Department of Agriculture 2013 Berry release. Washington and Oregon berry crops: Acres, yield, production, price, and value, 2010–2012. U.S. Dept. Agr., Natl. Agr. Statistical Ser., Washington, DC
U.S. Department of Agriculture 2015 Blackberry area harvested, yield, production, utilization, price and value by variety—Oregon: 2012–2014. In: NW noncitrus fruits and nuts 2014 preliminary press release. U.S. Dept. Agr., Natl. Agr. Statistical Serv., Washington, DC. 2 Apr. 2015. <http://www.nass.usda.gov/Statistics_by_State/Oregon/Publications/Fruits_Nuts_and_Berries/FRT1_1.pdf>
U.S. Department of Agriculture 2014 Table 33: Berries: 2012 and 2007. In: 2012 Census of Agriculture. U.S. Dept. Agr., Natl. Agr. Statistical Serv., Washington, DC
U.S. Department of Agriculture 2010 Table 6: Organic berries harvested from certified and exempt organic farms: 2008. In: Organic production survey (2008), 2007 Census of agriculture. U.S. Dept. Agr., Natl. Agr. Statistical Serv., Washington, DC
U.S. Department of the Interior 2013 U.S. Department of the Interior, Bureau of Reclamation, AgriMet. Boise, ID. 5 Apr. 2015. <http://www.usbr.gov/pn>