麻豆传媒

Organic Agriculture Centre of Canada

Nothing says summer quite like fresh fruit, and strawberries and raspberries are certainly popular among Canadians. Although these fruits are often grown conventionally throughout the country, there is a steadily growing demand for organically produced foodstuffs of all sorts, including berries. Most organic strawberries and raspberries currently available in Canadian supermarkets are grown in California, and leave a significant environmental footprint by being flown, trucked, or otherwise transported thousands of miles to our stores.

Scientists participating in Canada鈥檚 Organic Science Cluster (OSC) are studying the merits and possibilities of producing organically grown strawberries and raspberries in high tunnels, also known as hoophouses. Their goal is to provide growing systems that will allow Canadian producers to cultivate these high-value fruit crops in protected conditions, resulting in quality fruit for Canadian stores and consumers.

The research team includes scientists from Agriculture and Agri-Food Canada (AAFC) centres in Quebec, Universit茅 Laval, and industry partners.

High tunnels are unheated, relatively inexpensive greenhouses composed of metal hoops covered in a single layer of plastic film. They are excellent tools to help producers extend their growing seasons and improve farm productivity, while also protecting crops from weather extremes, and reducing the potential for pest and disease problems.

A wide number of crops can be grown in high tunnels, including cut flowers, field vegetables, and some types of small, high-value fruit such as strawberries and raspberries.聽 In temperate climates such as Canada鈥檚, the tunnels can extend the growing season, by increasing temperatures for crop production in spring, autumn and sometimes winter (depending on market demands), and also prevent rain, hail, and other types of precipitation from damaging fragile crops. Tunnel-grown perennial fruit-bearing plants are also protected from winter damage and can break dormancy and begin growing weeks earlier than their counterparts grown under traditional outdoor conditions and subject to all aspects of weather.

The OSC researchers are working with day-neutral strawberry cultivars. Day-neutral strawberries differ from the more common short-day varieties in that they develop flower buds all season long, and thus tend to be everbearing. The more traditional strawberry cultivars form their flower buds in autumn for next season鈥檚 crop, which is then produced for a relatively short season of 4-8 weeks.

Day-neutral strawberries, for which there is a breeding program in Quebec through a separate project with AAFC, can be excellent crop choices for producers because they are abundant much later in the growing year, when regular strawberries have long since stopped producing. Some varieties are less winter hardy, but growing them in tunnels can alleviate these concerns. There is also less risk of disease and pest problems and weed infestation, which means a reduced use of plant health products, helping to result in a lower environmental footprint for food production.

The OSC team of scientists is developing a system for container-grown organic day-neutral strawberries, providing them with proper organic fertilization and an optimal cropping period of up to three months. They are growing their plants in a certified organic medium that includes peat from the first peat moss operation to have been certified for Responsible Peatland Management through the Veriflora accreditation system ().

Raspberries command high prices in grocery stores, but their season can be very brief, with harvest and berry quality hampered by weather issues including rain and excessive humidity. The OSC researchers are working with everbearing raspberry cultivars selected for excellent fruit quality and flavour. Fall-bearing red raspberries can produce from late July until frost, unlike traditional raspberries that produce one crop in early to midsummer.

With both types of fruit crops, the OSC researchers are comparing the organic fertilization system they are developing with conventional systems using synthetic fertilizers.聽 They measure such factors as the fertility of the growing mediums, crop growth, crop yield and fruit quality.

Ultimately, the researchers鈥� goal is to develop effective organic growing systems for both strawberries and raspberries that will be protected from the vagaries of Canadian growing seasons. These systems will allow Canadian small fruit producers to cultivate high quality, organically grown crops that will appeal to consumers because they are grown 鈥渉ere at home鈥�, providing great food while also being environmentally friendly.

This article was written by Jodi DeLong on behalf of the OACC with funding provided by Canada鈥檚 Organic Science Cluster (a part of the Canadian Agri-Science Clusters Initiative of Agriculture and Agri-Food Canada's Growing Forward Policy Framework).聽 The Organic Science Cluster is a collaborative effort led jointly by the OACC, the and industry partners. For more information: oacc@dal.ca or 902-893-7256.


Posted July 2011