JOBNAME: horts 43#2 2008 PAGE: 1 OUTPUT: February 13 20:52:49 2008 tsp/horts/158649/02625 HORTSCIENCE 43(2):494–499. 2008. Vestberg et al., 1999). However, small fruit production on cut-over peatlands can be challenging. Intensive drainage required dur- Growing Black Chokeberry ing peat harvesting results in a deep and unstable water table level that represents a (Aronia melanocarpa)in risk of water deficit for subsequent plantings. The water table level may periodically re- Cut-over Peatlands main high as a result of the low hydraulic conductivity of peat with associated risk Julie Bussie`res, Ste´phanie Boudreau, Guillaume Cle´ment–Mathieu, of anoxia in the root zone. Moreover, the Blanche Dansereau, and Line Rochefort1 remaining peat has a low thermal conductiv- De´partement de Phytologie, Universite´ Laval, Que´bec, QC, G1V 0A6, ity, is highly acidic, and has a low nutritional content (Myllis, 1996; Wind-Mulder et al., Canada 1996). Hence, fertilization is required for Additional index words. bog, peat, rehabilitation, reclamation, small fruit, northern berries plant growth and productive fruit yield in cut-over peatlands (Noormets et al., 2004; Abstract. This project was established to evaluate the feasibility of black chokeberry Paal and Paal, 2002). [Aronia melanocarpa (Michx.) Ell.] culture on Canadian cut-over peatlands and to define The objectives of this project were to its appropriate production practices. We tested the effects of different fertilizer rates, evaluate the feasibility of black chokeberry application methods, and mulches on the vegetative development and berry production (Aronia melanocarpa) culture on Canadian of seedlings over a 6-year period (2000 to 2006). Fertilization was essential for survival cut-over peatlands and to define its appropri- of the plants. A low fertilizer rate (131 g/plant of 1.7N–4.1P–12K) ensured adequate ate production practices. vegetative development for good establishment. Applying such a rate for 2 consecutive years proved to be more beneficial than a single dose of fertilizer for increasing plant Materials and Methods height, crown width, and height growth. However, fruit yield was best when fertilized with the highest dose tested (550 g/plant of 3.4N–8.3P–24.2K). Black plastic mulch had a Two experiments were established at positive effect on height, width, and growth of the plants. More weeds were observed St-Bonaventure cut-over peatlands (lat. when the fertilizer was applied to the surface as compared with soil incorporation. 45°57#N, long. 72°42#W) southwest of However, this study revealed that black chokeberry is tolerant of weeds. Based on these Quebec, Canada. This bog peatland was results, black chokeberry is a promising plant for the management of cut-over peatlands originally drained for peat harvesting using for both vegetative growth and fruit production. the Haku-Peco technique (Andriesse, 1988) and operations ended in 1999. Fields were then flattened and additional drains were In Eastern Canada, peatlands are mined Among small fruits native to North Amer- dug to improve drainage. Peat depth varied for the horticultural properties of peat. When ica, black chokeberry (Aronia melanocarpa) from 47 to 115 cm (average, 78 cm; median, peat mining ends, the natural revegetation of is a promising candidate for use in cut-over 81 cm) and peat fields were 11 to 41 m wide the site is usually slow and scarce (Poulin peatlands. This species produces black edible and 250 m long on average. Nutrient content et al., 2005). Generally, ecological restora- fruits, readily eaten by birds, and is known was lower than the average peat chemistry tion of cut-over peatlands follows peat har- for its low maintenance requirements; slight for natural or cut-over peatlands (Wind- vesting with respect to the ‘‘no net loss’’ pruning is required and low occurrence of Mulder et al., 1996): 195.5 mgÁkg–1 of –1 –1 policy for the management of wetlands in pests and diseases has been observed (Finn, N-NH4, 8.3 mgÁkg of N-NO3, 12.9 gÁkg North America (Lynch-Stewart, 1992). Plant- 1999; McKay, 2001; Richer et al., 1997; Strik of total nitrogen, 28 mgÁkg–1 of phosphorus, ing small fruit plants on cut-over peatlands et al., 2003). Fruits also have antimutagenic 121 mgÁkg–1 of potassium, and 9 mgÁkg–1 of could be considered a complement to eco- properties resulting from their high antho- copper. Electric conductivity was higher logical restoration (Rochefort et al., 2003) or cyanin content (Gasiorowski et al., 1997). (338 mSÁcm–1) and pH (3.7) was similar to as a reclamation option. Berry plantations in Black chokeberry is already commercially that reported for cut-over peatlands. restoration projects could increase landscape grown, especially in Europe, where its fruits The nearest meteorological station heterogeneity and facilitate the return of are used in several juices, alcoholic or ener- (Drummondville: 45°52#N, 72°28#W) re- typical peatland bird species. As a reclama- gizing drinks, and in food colorant. ported annual average precipitation of tion option, added value could be gained Very little research on small fruit culture 1125 mm, of which 349 mm falls as snow, from formerly abandoned sites. on cut-over peatlands has been done because as well as mean temperatures of –10.7 °Cin large-scale industrial peat harvesting is rela- January and 20.8 °C in July with an annual tively recent. The first small fruit plantings on average of 5.9 °C (Environment Canada, industrial cut-over sites were done in Europe 2006a; equivalent of USDA Hardiness Zone in the mid-1970s (Paal, 1992). Most plantings 4b). Total rainfall for the growing season Received for publication 23 Oct. 2007. Accepted are found in Estonia, where blueberry (Vac- (May to September) was 606 mm in 2000, for publication 10 Dec. 2007. cinium angustifolium Ait.) and cranberry 389 mm in 2001, 431 mm in 2002, 483 mm in This study was supported by the Natural Sciences and Engineering Research Council of Canada (V. oxycoccos L.) are also successfully grown 2003, 492 mm in 2004, and 482 mm in 2005 (NSERC) and by industrial partners of the Indus- on cut-over peatlands (Noormets, 2006; (Environment Canada, 2006b). Water table trial Research Chair in Peatland Management led Noormets et al., 2004; Paal, 1992; Paal and depth measured in one well throughout the by Line Rochefort. Paal, 2002). A few small fruit trials have been summer of 2002 remained below 50 cm from We thank Fafard & Fre`res lte´e, especially Juana done on Canadian cut-over peatlands, but July to September. Elustondo, for their implication and support in this data are rudimentary and not easily available. Expt. 1: Fertilizer rates. Seedlings (tray project. We also thank research assistants who Cut-over peatlands are interesting grounds of 45 plants or 110 cm3, height unrecorded; participated in field work: Annie Jacob, Sharon for berry production because they are patho- Phytoclone and Que´bec Multiplants nursery) Boisvert, Luc Miousse, Rosalie Cliche, Patrick gen-free and initially weed-free (Virkaja¨rvi were planted between 8 May 2000 and 16 Faubert, Ariane Masse´, Jacinthe Letendre, and Ve´ronique Bouchard. Finally, we are grateful to and Huhta, 1996). Because cut-over peat- June 2000. Date of planting was not recorded anonymous reviewers for useful comments and lands have never received fertilizers or pes- precisely because the black chokeberry plan- suggestions on earlier drafts of the manuscript. ticides, there is a potential for establishing tation was part of a larger reclamation project 1To whom reprint requests should be addressed; organic production of fruits, vegetables, or realized by the peat company and involving e-mail [email protected] medicinal plants (Kukkonen et al., 1999; other species. Planting was done successively 494 HORTSCIENCE VOL. 43(2) APRIL 2008 JOBNAME: horts 43#2 2008 PAGE: 2 OUTPUT: February 13 20:52:53 2008 tsp/horts/158649/02625 on each experimental block and seedlings Seedlings [110 cm3, mean height (± SD) of a row to avoid edge effects. Height were randomly assigned to each treatment. of 44.8 cm (± 4.5); Aiglon nursery] were (centimeters) was measured as in the first Plants were planted at 1.5 m spacing within planted on 17 and 18 May 2004 at the same experiment. Width (centimeters) was calcu- rows with 3 m between rows for a density of density as in the previous experiment and lated from the average of two crown width 2222 plants/ha. randomly assigned to blocks and treatments. measurements on each plant. Measurements Four fertilizer rates were tested to deter- Seven treatments were applied: 1) control were taken above plant canopy parallel and mine the optimal rate for establishment and without fertilizer or plastic mulch (C); 2) perpendicular to the row. Weed coverage vegetative development of a black choke- 131.2 g/plant applied to the surface without (percent) was rated visually on a scale of berry planting on cut-over peat fields. These mulch (1/2Fs); 3) two applications of 131.2 g/ 1 to 5 for each experimental unit: 1 for 0% rates were chosen based on recommendations plant applied to the surface in both Spring to 20% groundcover occupied by weeds, for field-grown broadleaf shrubs (Hamel, 2004 and 2005 without mulch (1/2Fs·2); 4) 2 for 21% to 40%, 3 for 41% to 60%, 4 1986). Based on the chemical analysis of 262.4 g/plant applied to the surface without for 61% to 80%, and 5 for 81% to 100%. the residual peat substrate, 275 g/plant mulch (Fs); 5) 262.4 g/plant applied to the The middle value of each class was used in (610 kgÁha–1) of added fertilizer (3.4N– surface with mulch (FsM); 6) 262.4 g/plant statistical analysis and results.